CO3 2006 Posters
Poster Session 1 - Thursday Evening
P1 Gin Morgan (Columbia University)
Numerical Matching to Sample in Rhesus Macaques (Macaca mulatta)
Past research with rhesus macaques has shown ordinal competence with numerical stimuli, though it is  unclear exactly how numerical values are represented and if different values are represented in different ways.  This experiment uses a computerized delayed matching to sample paradigm with all values 1-9 and stimuli varied across multiple dimensions.  This experiment aims to determine the extent of rhesus numerical competence and which mechanism or mechanisms are used to form a mental representation of, and compare, numerical stimuli. 
P2 Anna Wilkinson & Kimberly Kirkpatrick (University of York, UK)
Complex Catching and Tracking Behavior in Pigeons
Pigeons have been shown to track moving objects using a complex tracking strategy; however, the underlying mechanisms are still unknown. Four pigeons were trained in a customized operant chamber in which one side was made up of a touch screen and video monitor. They were presented with a stimulus that could start from any side of the screen and travel horizontally or vertically to the other side. Test trials were randomly intermixed with training trials; in these the stimulus made a sudden 90 deg turn. Additional tests were given where the object disappeared and then reappeared on its original trajectory or on the turn trajectory. The pigeons adapted to the test motions, with their performance improving over sessions. Examination of their peck errors revealed that on normal turn trials, their initial strategy persisted beyond the turn. However the brief disappearance of the object prior to the turn resulted in an improvement in adaptation to the post-turn motion.
P3 Steven W. Badelt, Jack W. Judy, Aaron P. Blaisdell (UCLA)
A Behavioral Model for Testing Reliable Brain Computer Interfaces in Rat
Brain-computer interfaces (BCIs) are designed to decode patterns of neural behavior and rehabilitate patients by substituting machine function for incurred disabilities. However, this technology has not enabled patients to reliably interact with the environment.  Here, we propose a two-lever operant task which supports the testing and design of reliable BCIs in a rat model.  The operant schedule first requires rats to reliably produce a pattern of lever pressing.  Later, use of the BCI will be substituted for lever-pressing activity.  The schedule allows the behavioral definition of the rat’s intent to subsequently lever-press, or activate the BCI.  Our preliminary data indicate that rats can be conditioned to correctly produce the lever-pressing pattern in >99% of trials.  The method used herein provides a mechanism for developing reliable BCIs in a rat model, with eventual applications to primate research and for human patients.
P4 Jochen Barth (Maastricht University) & Josep Call (Max Planck Institute for Evolutionary Anthropology)
Tracking the Displacement of Objects: A Series of Tasks with Great Apes and Young Children
We administered a series of object displacement tasks to twenty-four great apes and twenty-four 30-month-old children. Objects were placed under one or two of three cups by visible or invisible displacements. The series included six tasks: Delayed response, inhibition test, A-not-B, rotations, transpositions, and object permanence. Apes and children solved most tasks performing at comparable levels except in the transposition task, in which apes performed better than children. Ape species performed at comparable levels in all tasks except in single transpositions, in which chimpanzees and bonobos performed better than gorillas and orangutans. All species found non-adjacent trials and rotations especially difficult. The number of elements that changed locations, the type of displacement, and having to inhibit predominant reaching responses were factors that negatively affected the subjects’ performance.
P5 Benjamin M. Basile & Robert R. Hampton (National Institute of Mental Health, now at Emory University), Stephen J. Suomi (National Institute of Child Health and Human Development) & Elisabeth A. Murray (National Institute of Mental Health)
Assessment of Memory Awareness in Capuchin Monkeys (Cebus apella)
Humans, apes, and rhesus monkeys demonstrate memory awareness by collecting information when ignorant and acting immediately when informed.  In the current study, five capuchin monkeys searched for food after either watching the experimenter bait one of four opaque tubes (seen trials), or not watching (unseen trials). Monkeys with memory awareness should look into the tubes before making a selection only on unseen trials because on seen trials they already know the location of the food. In Experiment 1 one capuchin looked more often on unseen trials. In Experiment 2 we ensured that the monkeys attended to the baiting by interleaving training and test sessions. Three monkeys looked more often on unseen trials. In Experiment 3 we increased the effort required to look, predicting a larger difference between seen and unseen trials. No monkeys looked more often on unseen trials. These findings provide equivocal evidence for memory awareness in capuchin monkeys.
P6 Toyomi Matsuno (Kyoto University, JSPS) & Masaki Tomonaga (Kyoto University)
Stream/Bounce Perception in Chimpanzees (Pan troglodytes)
The stream/bounce stimulus is an ambiguous motion event; identical visual objects move directly toward and the two objects overlapped completely before they past one another. They appear either to stream past one another or to bounce off each other. Previous studies have shown that the stimulus is dominantly perceived as "stream" by human observers and that attention-capturing stimuli (such as sounds, flashes, and bounce event) synchronously presented with the overlap of the objects turn the perception into "bounce". In this study, behavioral experiments using an object-tracking task revealed characteristics of stream/bounce perception in chimpanzees (n=5). First, chimpanzees did not show a tendency of dominant "stream" perception of the stream/bounce stimulus. Second, chimpanzees significantly increased "bounce" responses depending on the addition of a synchronous bounce event to the display as humans did. These results suggest both similarity and difference between chimpanzees and humans in perceptually organizing movement of multiple objects.
P7 Joshua S. Beckmann & Michael E. Young (Southern Illinois University at Carbondale)
Novelty as a Feature in the Feature Positive Effect in Humans
We investigated the role of the relative salience of present and absent cues in Feature Positive (FP) and Feature Negative (FN) tasks. Past literature has shown, across various methods and species, that FP tasks are learned more easily than FN tasks, giving rise to what is known as the Feature Positive Effect (FPE).  Experiment 1 was devised to investigate the role of presence/absence salience in the FPE through manipulation of the context (constant versus varied) that was paired with the feature. The results suggest that novel contextual elements may be salient enough to eliminate the FPE, creating a Feature Negative Effect (FNE) under certain conditions. Experiment 2 replicated the FNE and the addition of a testing phase confirmed that participants in the FN task judged novel stimuli to be strong positive predictors whereas participants in the FP task did not.  These results are problematic for contemporary associative learning models.
P8 Miranda C. Feeney & William A. Roberts (University of Western Ontario)
Studies of Impulsivity versus Self-control in Rats on the Radial Maze
Traditional assessments of “impulsivity” versus “self-control” in animals have studied choice in an operant chamber; findings have indicated a lack of ability to foresee future consequences and a discounting of delayed rewards.  The current studies examined impulsivity in the context of foraging on the radial maze.  Rats chose between arms yielding a delayed large reward and arms yielding a more immediate small reward.  In Experiment 1, rats showed a preference for arms providing 1 reward pellet after a 1-s delay over arms providing 1 pellet after a 10-s delay; this preference continued as the reward after 10-s was increased to 5 pellets.  In Experiment 2, however, reward magnitude differences were present from trial 1, and results differed from the typical operant finding, with rats visiting delayed-large-reward arms before immediate-small-reward arms.  Experiment 3 explored the possibility that differential secondary reinforcement experiences on maze arms during delays facilitated self-control.
P9 Tiffany Galtress & Kimberly Kirkpatrick (University of York, UK)
Reward Value and Reward Timing are Not Independent.
Rats were initially trained on an instrumental FI60-s peak procedure. Increasing the value of the reward by increasing the number of food pellets led to a leftward shift in the peak function during non-reinforced probe trials, whilst reducing the value of the reward by pairing the food pellets with lithium chloride led to a rightward shift in the peak function during non-reinforced probe trials. These findings suggest that changing the motivational value of the reward affected the perceived delay to reward.
P10 Chris Harshaw, Susan Schneider, & Robert Lickliter (Florida International University)
Superstition in the One-Day-Old? Inter-Call-Interval and Auditory Preference in Bobwhite Quail Neonates
The interaction of species-typical patterns of behavior with arbitrarily chosen schedules of stimulus presentation is a topic of interest to a wide range of researchers. This study presents data demonstrating a near linear relationship between length of inter-call-interval (ICI) and naïve preferences for variants of bobwhite maternal calls in 24-hour-old bobwhite quail chicks. Naïve chicks were given 5-minute simultaneous choice tests between two variants of the same maternal call, differing only in length of ICI. Calls with shorter ICIs were found to be significantly preferred over calls with longer ICIs, the degree of preference being proportional to the difference in ICI between the two calls. It seems likely that this phenomenon is the result of chance contiguities between specific behaviors of the chick (e.g. distress vocalizations) and specific features of the maternal call being played during testing. Sequential analyses exploring this hypothesis will be presented.
P11 Brooke Poerstel, Carol Dwan, Bridgette Byrd, Nick Hahn, Patrick McKinney, Jessie Ramsey, Rebecca M. Rayburn-Reeves & Mark Galizio (University of North Carolina Wilmington)
The Importance of Response Topography in Olfactory Discrimination in Rats
Using a two-choice repeated discrimination learning procedure with olfactory stimuli, we have found rapid, single-session, learning in rats when the response involved digging in scented sand to produce food pellets. Experiment 1 attempted to replicate these findings using a nose-poke response with three discriminative stimuli, but rapid learning was not obtained. Discrepancies between Experiment 1 and our earlier findings might have been due to increasing the number stimulus choices from two to three in Experiment 1 or to differences in response topography: nose-poke vs. digging. To examine the importance of response topography, Experiment 2 tested repeated discrimination learning with three choices and a more active response requirement. Rapid learning in this study suggests that response topography is a major influence on olfactory discrimination learning. 
P12 Elizabeth J. Rahn (University of Georgia), Tyson L. Platt, Daniel Bradford & Martha Escobar (Auburn University)
Inhibition of Delay in Appetitive Conditioning: Retardation Test
Inhibition of delay refers to the observation that conditioned responding to a long conditioned stimulus (CS) tends to be delayed until the final segments of the CS, which are contiguous with the unconditioned stimulus (US; Pavlov, 1927).  Rescorla (1967), using dog subjects in an aversive preparation, conducted summation and retardation tests for the initial segments of a long CS, and reported that the initial segments of the long CS became inhibitory.  A previous experiment from our laboratory, using an appetitive paradigm with rat subjects, failed to obtain evidence of conditioned inhibition to the initial segments of a CS trained with an inhibition of delay paradigm, when assessed via a summation test.  Using the same appetitive preparation, the current study revealed retarded acquisition of a conditioned response to the initial segments of the CS.
P13 John Townsend-Mehler (Michigan State University)
Bumblebees and Honeybees:  A Comparison of Foraging Decisions in a Changing Environment
When a food source becomes non-rewarding, all foragers must decide if and how often to revisit that site, when to look elsewhere, and for many insects, when to return to the nest.  In this experiment we compared the foraging behavior of honeybees and bumblebees.  Foragers were given permanent access to a constant low reward feeder, and then a limited amount of experience (either long or short) at a variable feeder, offering first a high payoff and then no payoff.  Once the variable feeder ceased to be rewarding, both feeders and the hive were monitored.  I observed strong species differences in sampling rates at the variable high-reward site, willingness to reinitiate foraging at the low reward site, as well as subsequent return visits to the nest.  These results suggest that there are fundamental differences between species in terms how each utilizes information from past experience to make foraging decisions.  
P14 Tania J. Bettis & Lucia F. Jacobs (University of California at Berkeley)
Sex Differences in Spatial Cognition in Mice
Sex differences can be an important tool for comparative cognition. Females and males may utilize different cognitive solutions to solve similar problems such as encoding spatial cues. We addressed this question in the laboratory mouse in experiments using cohorts of 10 mice per sex. These experiments included novel object recognition which has never been shown to be sexually dimorphic. This task is mediated by a subfield of the hippocampus (CA1). The mice were habituated to two identical objects in a 5 min session 24 hours before the test session. During the test session the mice were presented with a novel object paired with a familiar object. Females spent significantly more time with the novel object than the familiar object while males did not show this bias. These results will be presented along with the results from ongoing studies of sex differences in cue use in various mazes. 
P15 Kent D. Bodily, Bradley R. Sturz, & Jeffrey S. Katz, (Auburn University)
Generalization of Spatial Rules Instead of Integration of Spatial Maps in a Virtual Open-Field
A 3-D virtual-environment open-field analogue of Blaisdell & Cook’s (2005) pigeon foraging task was constructed to determine if humans, like pigeons, were capable of integrating separately learned spatial maps. Participants searched for a goal among 16 raised cups arranged in a 4 x 4 grid. During separate training phases, participants learned to locate the goal between two landmarks (Phase 1: blue T and red L) and down and left of a single landmark (Phase 2: blue T). During test trials, participants made 6 unrewarded choices in the presence of the red L alone. Cup choices during testing were analyzed to assess participants’ strategies: generalization (Phase 2), association (Phase 1), or integration (combination of Phases 1 and 2). Results suggested participants used a generalization strategy which was confirmed by two control groups. Comparative implications of the data are discussed.
P16 Mona Buhusi (University of North Carolina at Chapel Hill), Richard Chu (Duke University), Melitta Schachner (University of Hamburg), Patricia Maness (University of North Carolina at Chapel Hill) & Catalin V. Buhusi (Duke University)
Impaired Working Memory in a Spatial Task in CHL1 KO Mice
Cell adhesion molecules play important roles during development including axonal growth, pathfinding, and neural plasticity.  The "Close Homolog of L1" (CHL1) gene is associated with human mental retardation and schizophrenia.  We assessed spatial navigation in male CHL1 null mutants, heterozygotes, and wildtype littermate controls (C57BL/6) in a modified radial arm maze.  The results suggest a reduced working memory capacity during spatial navigation in CHL1-KO mice relative to controls. 
P17 Xiaoqian J. Chai  & Lucia F. Jacobs (University of California Berkeley)
Sex differences in the Construction of the Cognitive Map: A Spatial Navigation Study in Virtual Environments
Sex differences in spatial strategy have been reported in multiple species. In humans, comprehensive cue use has not been studied in previous experiments. The present study uses computer generated virtual environments to investigate human sex differences in the construction of the cognitive map. We hypothesize that females rely more on topology-like maps constructed mainly from local positional cues, whereas males rely more on bearing maps based on directional cues such as distal objects, geometric and gradient information. Subjects are asked to navigate in a computerized open field and locate a hidden object. Each subject is trained with an environment where all cues are present, then tested on modified environments where some cues are removed, displaced or rotated. We predict males should be less affected by manipulations of positional cues and females should be less affected by manipulations of directional cues. 
P18 Fred Dyer (Michigan State University
Multiple Representations of Sun-Compass Information in Honey Bees
To use the sun as a compass, honey bees compensate for its movement relative to earth-bound landmarks. This study examined whether bees that have learned the sun's course relative to one foraging route can transfer this knowledge to a different foraging route.  Bees were trained to fly to food in narrow channels, which served as the reference frame for learning the sun's course.  Covering the channels forced bees to rely upon memory of the sun’s position. Waggle dances, which signal flight directions relative to the sun, revealed where the bees estimated the sun to be. When bees that had already learned the sun were made to fly in a different direction, they quickly learned the angle of this new tunnel relative to the sun.  However, this angle was not compensated for the sun's subsequent movement.  This suggests that bees can encode the sun's position in both time-compensated and non-compensated formats.
P19 Sylvain Fiset (Université de Moncton in Edmundston)
Searching in the Center : Do Guinea-Pigs Encode Relative Distance?
This study was aimed at determining whether guinea-pigs encode absolute or relative distance to locate the center of a configuration of landmarks. The guinea-pigs’ task was to locate a hidden platform surrounded by landmarks placed inside a pool. In Experiment 1, the platform was centrally placed between two landmarks. In Experiment 2 and 3, it was surrounded by four landmarks forming a square. On control test, the landmark array remained the same as in training. On expansion tests, the size of the array was double along one dimension (Experiments 1 and 2) or along both dimensions (Experiment 3). On control tests, the guinea-pigs searched at the center of the landmark array. On expansion tests, the guinea-pigs tended to search either at the training distance from one of the landmarks or at the center of the array, suggesting that guinea-pigs encode and use both relative and absolute distances from the landmarks.
P20 Michelle Hernández & Jeffrey S. Katz (Auburn University)
Pigeons Can Use Optimal Paths in a Computerized Task
Pigeons that learned to move a target toward a goal on a computer screen by responding to arrows representing distinct directions (i.e., left, right, down, up) were transfer tested with a barrier placed between the start and goal locations. The target could not be moved through the barrier. Optimal path use was analyzed in relation to the effects of distance and angle of the configurations (i.e., specific relationship among target-barrier-goal). Pigeons successfully avoided the barrier but when the barrier blocked the goal at the shortest distance, the pigeons incorrectly selected the arrow that would move the target through the barrier toward the goal. Next, after training with the barrier, the pigeons were again tested with the same configurations but in novel angles. Movement toward the barrier decreased and good transfer was found for some configuration types indicating pigeons can learn optimal paths.
P21 Edward Lorek & Michael F. Brown (Villanova University)
Sex Differences in Human Spatial Pattern Learning
The present study was focused on the extent to which men and women demonstrate spatial abilities that correspond to the predictions made by the theory that human sex differences in spatial abilities are based on our evolutionary history as hunter-gatherers (Silverman & Eals, 1992). To investigate this hypothesis, we used a version of the human analog pole-box task developed by Upton (2004) and based on the spatial pattern learning task for rats introduced by Brown and Terrinoni (1996). The task requires subjects to locate a consistent spatial arrangement of correct buttons within a 6 x 6 matrix of blank buttons over the course of 60 trials that is either consistently located across trials (Location Condition) or randomly located across trials (Pattern Condition). The hunter-gatherer hypothesis predicts that females will outperform males in the Location Condition and males will outperform females in the Pattern Condition. Little, if any, support for this prediction was obtained. 
P22 Tomas Pickering, Erica H. Kennedy, Bettina von Ammon, Nicole Scott, Dorothy Fragaszy, & Josh Wintje (University of Georgia)
Capuchin Monkeys (Cebus apella) Complete Two-Dimensional Mazes More Efficiently Following Practice With Numerous Exemplars
Can monkeys navigate mazes that require attention to multiple features more efficiently following practice with numerous exemplars?  We presented three capuchin monkeys with 192 two-dimensional digital mazes that they encountered four to seven times in replicates.  Mazes contained one to five binary choices including zero to three “non-obvious” choices (where the incorrect path was in the Euclidean direction of the goal).  After each replicate, we presented a subset of twenty-four mazes to assess variables that we hypothesize reflect the monkey’s attention to the relevant spatial relations in this task.  With continuing experience at solving the mazes, monkeys a) made fewer errors, particularly on non-obvious choices, b) self-corrected their errors before striking the end of path proportionally more often, c) and looped the cursor 360º less frequently.  These findings indicate that monkeys can learn to manage attention in a task involving sequential and concurrent decisions about travel. 
P23 Cynthia Wei (University of Nebraska)
A Test of the Social Complexity Hypothesis: Transitive Inference in Clark's Nutcrackers and Azure-winged Magpies
According to the social complexity hypothesis, life in large, stable social groups demands sophisticated cognitive abilities.  Comparing two closely related species, Bond et al. (2003) showed that the highly social pinyon jay (Gymnorhinus cyanocephalus) outperforms the relatively nonsocial western scrub jay (Aphelocoma californica) in dyadic tracking and transitive inference tasks.  While the pinyon jay’s superior performance might be attributed to the demands of social life, it might also be the result of their superior spatial abilities.  To investigate this possibility, we compared a relatively social bird that does not cache, the Azure-winged magpies (Cyanopica cyanus), to a relatively nonsocial species known for their excellent spatial abilities, Clark’s nutcrackers (Nucifraga columbiana) on dyadic tracking and transitive inference tasks.  Our preliminary results indicate that magpies and nutcrackers do not differ in acquisition rates or accuracy in dyadic tracking, and neither species appears to perform as well as pinyon jays in these tasks. 
P24 Anna Waisman & Lucia F. Jacobs(University of California, Berkeley)
Flexible Spatial Cue Use in a Food-storing Mammal
Although most animal studies on the use of spatial cues in place location tasks have concentrated on the use of rigid hierarchical strategies, new data suggests that these strategies do not adequately explain animal behavior. We plan to explore the ability of a food-storing mammal, Sciuridae (squirrel), to adopt different heuristics depending on the availability and stability of cues in the environment. We will first demonstrate that squirrels use cues in the same hierarchical manner as other food-storing animals and that this hierarchy is then disrupted in cue conflict situations when two subordinate cue types are put in conflict with the single dominant cue type. We will also establish how cue stability interacts with cue use. Preliminary results show: that squirrels are comparable to other animals in their use of spatial cues, that cue majority overrides cue hierarchy, and that cue stability is a main predictor of cue use. 
P25 Carrie R. Rosengart (California University of Pennsylvania) & Dorothy M. Fragaszy (University of Georgia)
Spatial Search Accuracy on Probe and Non-Probe Trials in Capuchin Monkeys (Cebus apella)
In spatial search tasks probe trials are frequently used to assess search accuracy without the confound of a reward.  Capuchin monkeys were tested on a search task where they were required to find a raisin (after 0-120 second delays) that they had observed being hidden in a sandbox. Accuracy was determined on non-probe trials based on the distance of the first search attempt from the actual hiding location. On probe trials, the raisin was removed prior to the search attempt.  The monkeys were then allowed to search for 30 seconds. Multiple searches were allowed. On the non-probe trials, the delay impaired search accuracy. However, on the probe trials, the monkeys showed similar search patterns regardless of the length of the delay period.  These findings indicate that though initial searches were impaired by a delay period, the monkeys were able to accurately focus their searches if given additional search opportunities.
P26 Nicole M. Scott, Dorothy Fragaszy (University of Georgia), & Charles Menzel (Georgia State University)
Chimpanzee Strategies to Solving Spatial Relation Problems: Managing Concurrent and Asymmetric Relations
Solving spatial problems requires managing relations between objects and surfaces. We predicted that managing concurrent relations between an object and a surface would be more difficult than managing a single relation. Four adult chimpanzees placed a rigid stick into a groove on a circular tray and then returned the tray to the experimenter. The sticks changed progressively from straight, to a cross, to a tomahawk shape. In this manner, the number of concurrent relations required to insert the stick increased. Subjects completed ten trials of each shape before progressing to the next. All subjects completed the series, but in a manner distinct from a human approach (i.e. direct placement into the groove). Chimpanzees used several strategies including sliding the stick over the surface and bimanual guidance. The asymmetric conditions were more difficult for them than the simple straight stick conditions as evidenced in more attempts and longer trials.
P27 Sarah A. Stamper & Gordon B. Bauer (New College of Florida)
Landmark Navigation in Honeybees (Apis mellifera): Snapshot Memory and Relative Position
Honeybees have the ability to use landmarks to navigate.  Two models proposed to explain landmark navigation by honeybees have been frequently suggested: snapshot memory and compass navigation.  An alternative model more commonly used to describe vertebrate landmark navigation is relative position. This study consisted of two experiments.  The first had a single landmark array and manipulated the size and distance to the goal of the landmark. The honeybees made predicable errors in search location and search time consistent with the snapshot model.  The second study had a two-landmark array and made the same manipulations but for either one or both of the landmarks. When both landmarks were manipulated the honeybees did not make search location errors, although they did have increased search times.  Results for the second study suggest the possibility that the honeybees could use a strategy of relative position under conditions of a constrained environment.  
P28 Bradley R. Sturz, Kent D. Bodily, & Jeffrey S. Katz (Auburn University)
Evidence for Spatial Integration in Humans
A sensory preconditioning procedure similar to that used by Sawa, Leising, and Blaisdell (2005) with pigeons was implemented for humans to test for spatial integration. Two separate groups searched a 3-D virtual environment for a goal in a 4 x 4 grid. First, both groups learned to locate a goal down and left of a single blue landmark. Next, participants were presented with five successive three-trial blocks consisting of two blue landmark trials followed by one preconditioning trial. Preconditioning trials lasted 30 seconds and consisted of the blue landmark paired consistently (Consistent group) or inconsistently (Inconsistent group) with a red landmark. Choice responses could not occur during preconditioning trials. Next, a single test trial occurred in which participants made choices in the presence of the red landmark alone. Results suggested only the Consistent group utilized an integration strategy and were consistent with those obtained with pigeons. 
P28A Daniel I. Brooks & Edward A. Wasserman (University of Iowa)
Same/Different Concept Learning with Trial-Unique Stimuli in Pigeons
A longstanding issue in same/different concept learning is the repeated use of stimuli across training trials, because such a procedure encourages individual or configural stimulus learning.  This issue prompted us to devise a means for generating trial-unique stimuli with which to investigate same/different concept learning.  Four pigeons were given a Two-Alternative Forced-Choice Same/Different task using trial-unique stimuli, which meant that every discrimination training trial was also a generalization testing trial.  These stimulus arrays were arranged in a 4 x 4 grid containing 16 cubes; each cube itself contained a 16-item array whose cells were filled with one of 16 levels of luminance.  Creating stimuli in this way afforded us a virtually endless set of unique patterns and allowed the controlled manipulation of the degree of similarity between individual stimuli in the task.
P29 Aaron P. Blaisdell (UCLA), Kosuke Sawa (Japan Society for the Promotion of Science—Nagoya University), W. David Stahlman, Kenneth J. Leising, Dana Gant (UCLA), & Michael S. Waldmann (University of Göttingen)
Causal Reasoning in Rats
Empirical research with nonhuman primates appears to support the view that causal reasoning is a key cognitive faculty that divides humans from animals. The claim is that animals approximate causal learning using associative processes. The present results cast doubt on this conclusion. Rats made causal inferences in a more basic task which taps into core features of causal reasoning without requiring complex physical knowledge. They derived predictions of the outcomes of interventions after passive observational learning of different kinds of causal models.  These competencies cannot be explained by current associative theories but are consistent with causal Bayes net theories.
P30 Erica Hoy Kennedy & Dorothy M. Fragaszy (University of Georgia)
Examining the Analogical Reasoning Capacity of Capuchin Monkeys (Cebus apella) using a Three-Dimensional Search Task
Analogical reasoning involves recognizing similarities among object relations when the objects themselves are dissimilar.  It has been argued that apes, but not monkeys, are capable of analogical reasoning.  This study investigates whether capuchin monkeys can use analogical reasoning in order to solve a three-dimensional search task that was modeled from a paradigm used in the developmental literature (i.e, Goswami, 1992).  The task involves hiding food under one of two opaque cups of different sizes and allowing the subject to search for food under the cup of analogous size in their own set of cups. Monkeys are first learning basic MTS. Next they will be exposed to two pairs of cups and required to search for food based on physical or relational similarity. It is expected that the monkeys will have more difficulty solving the analogical search task in comparison to the task based on physical similarity.
P31 Michael Lamport Commons (Harvard Medical School)
Horizontal Complexity and How Smart Animals Are
There are three major forms of task difficulty that should be taken into consideration in determining how smart animals are: Hierarchical complexity, g, and Horizontal complexity.  Classical information theory describes the number of “yes-no” questions it takes to do a task.  Each yes-no question is a bit.  The measure of  Horizontal complexity, then, is the sum of bits required by doing a task correctly.  Horizontal complexity is exemplified by short term memory span and length of behavioral chains that may be assembled in a stable manner.  There have been many studies of these  across a wide variety of species done in a number of ways.   Some examples will be reviewed.
P32 Patricia Wilson (Columbia University)
Order Information Task Comparing Monkeys and Humans
Three rhesus monkeys performed a Serial List Recognition (SLR) task containing 4 arbitrary photographs against varying numbers of distracters (2, 3, or 4). Responses were reinforced for selecting all the items in the list, regardless of presentation order, without selecting any distracters. A strong recency effect was found without any evidence of a primacy effect.  Human subjects were then asked to perform the same task to compare behavioral responses with an increase in the number of distracters (6, 7, or 8).  On the identical task humans showed both primacy and recency effects.  When the arbitrary photographs were changed to black and white fractals, human performance decreased and output order shifted to more closely mirror that found in monkeys.  A third Human condition that decreased the reaction time to match that of the monkey subjects resulted in further modification of the output order and accuracy away from primacy toward recency.   A fourth Human condition was intended to completely eliminate the participant’s ability to verbalize the stimuli.  Participants were asked to say “the” repeatedly throughout the session.  This condition is expected to result in further modification of human output order to mirror that of the monkey subjects.
Poster Session 2 - Saturday Evening
P33 Denise P.A. Smith & Stephen B. Fountain (Kent State University)
Medial Caudate Putamen Lesions and Rat Serial Pattern Learning
In prior research in our lab, MK-801, an NMDA receptor antagonist, disrupted serial pattern learning in rats when the serial pattern was a sequence of 24 response elements arranged in eight 3-element chunks.  The final element of the sequence violated the overall pattern structure.  MK-801 rats learned within-chunk elements as fast as controls, but showed permanent inability to learn the violation response and, to a lesser degree, chunk boundary responses.  In the present study, 6 rats received medial caudate putamen excitotoxic lesions later confirmed by histological analysis. Rats were then trained on the same pattern as in previous studies.  Medial caudate putamen lesions caused learning deficits for within-chunk elements and the violation element, but not for chunk-boundary elements.  Deficits were generally less severe than those caused by MK-801.  These results support the claim that serial pattern learning is subserved by multiple dissociable brain and cognitive systems.
P34 James D. Rowan (Wesleyan College), Amanda R. Willey, Eric P. Nolley, Brian M. Kelley (Bridgewater College), and Stephen B. Fountain (Kent State University)
Adolescence exposure to nicotine impairs adult serial-pattern learning in rats.
This experiment examines the effects of early exposure to Nicotine on adult higher cognitive function.  Weanling rats were injected 5 days a week for 5 weeks with 3.0, 1.0, 0.3 mg/kg nicotine or saline based on body weight (1 ml/kg). After 5 weeks off, all subjects were trained on the perfect run pattern (123 234 345 456 567 678 781 812) for 28 days receiving 5 patterns a day. Analysis of the data found the performance of the 1.0mg/kg nicotine group was significantly impaired compared with all other groups.  To our knowledge, this is the first evidence that long-term, low-level adolescent nicotine exposure significantly impairs higher cognitive functioning in adulthood.
P35 James D. Rowan (Wesleyan College), Barbara E. Rowan (James Madison University), Shannon M.A. Kundey (Yale University), and Nandini Sen (Wesleyan College)
The Effects of Pattern Dispersal on Acquisition of Alternation, Runs, and Perseveration Patterns on a Rat and Human Serial-Pattern Learning Task.
Theories of serial-pattern learning have discussed different types of rules but have little discussion whether all rules are learned with the same difficulty.  In an experiment using rats and humans (different but analogous procedures), subjects were divided into groups and required to learn 1 of 5 simple patterns (run-plus, run-minus, preservation, double alternation, and disrupted pattern) interleaved with another perseveration pattern. Subjects, both humans and rats, in all groups learned to track their pattern.  The data support the hypothesis that the perseveration rule is learned fastest even when overall effort is controlled for.  The perseveration pattern allowed for the fastest acquisition and the plus, minus, and alternation patterns were acquired at approximately the same rate.  
P36 Amber M. Chenoweth, Steven A. Wolfe, & Stephen B. Fountain (Kent State University)
“Extreme” Sequential Learning: Rats Learn 60-Element Interleaved Serial Patterns
Humans have the ability to chunk together information from nonadjacent serial positions in sequential patterns.  For example, human subjects typically learn the pattern, A-M-B-N-C-O-D-P-E-Q, by cognitively sorting pattern elements into component interleaved subpatterns:  A-B-C-D-E and M-N-O-P-Q.  Our earlier studies demonstrating similar capacities in rats showed that patterns composed of two interleaved subpatterns were difficult to learn, but that subpattern difficulty was nonetheless determined by subpattern structure.  In the present study, we investigated rats' ability to learn a 60-element interleaved pattern where one subpattern was one of two 30-element hierarchically organized patterns composed of either “runs” or “trills” chunks.  The other subpattern was composed of a repeating element.  Subpattern acquisition rates were correlated with the structural properties of component subpatterns.  The results indicate that rats are sensitive to the patterning of nonadjacent elements even in extremely long serial patterns and that several factors contribute to pattern tracking in interleaved patterns.
P37 Stephen B. Fountain & Amber M. Chenoweth (Kent State University)
A Serial Reaction Time Task for Rats: Individual Differences in Sequence Encoding
The serial reaction time (SRT) task is a popular procedure for assessing sequential learning capacity in human neuropsychology and functional imaging studies.  We developed an operant SRT procedure for rats that is a close analogue of the human SRT procedure.  It encourages rats to respond as quickly as possible to the successive positions of a light that appears in one of four positions in a horizontal array.  Rats press corresponding levers under the array of lights for brief pulses of hypothalamic brain-stimulation reward.  “Reaction times” (RTs) are similar to those observed in human studies, averaging 1000 msec or less for 1000-trial sessions. Rats learned a simple repeating pattern in this task in a single session; RTs were shorter for repeating patterns than for random sequences presented in blocks in the same session.  Rats showed individual differences in sequence encoding that appeared in their first session and remained consistent across sessions.  
P38 Amber M. Chenoweth & Stephen B. Fountain (Kent State University)
Central cholinergic systems are necessary for learning and retaining “exceptions-to-the-rule” in rat serial pattern learning.
We examined the effects of atropine, a muscarinic cholinergic antagonist, on acquisition and retention of serial patterns.  Rats were given daily i.p. injections of either saline or atropine sulfate (50 mg/kg) and trained to press levers in a specific order (the serial pattern) for brain-stimulation reward in an octagonal operant chamber.  The two groups learned the following pattern:  123 234 345 456 567 678 781 818.  Atropine exposure impaired acquisition for chunk boundary elements (the first element of chunks) and the violation element of the pattern, but did not impair acquisition for within-chunk elements.  Performance was unchanged in a subsequent drug-free day.  Similar deficits were observed in a retention test where saline-trained rats were exposed to atropine for one day.  The results indicate that intact central cholinergic systems are necessary for learning and retaining appropriate responses at places in sequences where pattern structure changes.
P39 Sara Crowell (New College of Florida), Heidi E. Harley (New College of Florida, The Living Seas at Epcot), Wendi Fellner & Leslie Larsen-Plott (The Living Seas at Epcot)
Vocal Productions of Rhythms by the Bottlenose Dolphin
This study is an in-depth analysis of vocalizations produced by a dolphin participating in a rhythm production study.  In the rhythm production study, the dolphin was shown one of six objects and reinforced for vocally producing a rhythm uniquely associated with that object.  An analysis of the dolphin’s vocal responses across eight months of the study revealed that the dolphin varied frequencies and durations across the rhythms while maintaining the structure of each rhythm. Stable characteristics of the vocalizations included incorporation of an upsweeping frequency contour into the long elements, and more broadband characteristics in the short elements.  These results demonstrate that dolphins represent rhythms in terms of relative durations and frequencies versus absolute durations and frequencies.  In addition, because the importance of contour in the dolphin’s vocal repertoire was evident throughout this study, these data suggest that dolphins may categorize whistles by contour. 
P40 Joseph Tremblay & William A. Roberts (University of Western Ontario)
Is the whole greater than the sum of its parts? Categorization of whole and partial geometric figures by pigeons
We report two studies that examined which properties of geometric figures pigeons attended to during discrimination training. In the first experiment, one group of pigeons was reinforced for pecking at different images of triangles and was nonreinforced for pecking at images of circles and ellipses. Another group saw only triangles and was reinforced for pecking at them. On test trials given after discrimination learning, both groups were shown novel whole and partial triangles, circles, and ellipses. The results indicated that any feature of a triangle was sufficient for it to be categorized as a triangle and that categorization of circle and ellipse test stimuli was dependent upon their similarity to the training stimuli. Similar procedures were used in a second experiment to find out if pigeons can learn the concepts of triangle and circle.
P41 Walter T. Herbranson (Whitman College)
Pigeons (Columba livia) learn visual categories based on angle of movement, but not angle of orientation
Pigeons can learn to categorize stimuli based on a wide variety of visual features.  However, not all kinds of categories are equally easy to learn.  Some can be learned with very little training, while others can only be acquired with extensive experience, if at all.  In these experiments, pigeons learned to categorize visual stimuli presented on a computer monitor.  When categorizing moving objects based on their speed and angle of travel, pigeons divided attention across both stimulus dimensions and performed nearly optimally.  When categorizing objects based on size and angle of orientation, pigeons selectively attended to size, even when attention to orientation was required for optimal performance.  These results indicate that categories based on angle can be relatively easy or relatively difficult for pigeons, depending on whether angle represents an orientation or a direction of travel.
P42 Tammy L.B. McKenzie (Brandon University) & William A. Roberts (The University of Western Ontario).
Categorization by Pigeons: The Role of Category Variability and Perceptual Similarity
The influence of category variability and perceptual similarity on categorization judgments by pigeons was examined. Two groups of pigeons were trained with two categories of horizontal lines. Group 1 was trained with a low variability short line category (lines similar in length) and a high variability long line category (greater variability in length). Group 2 was trained with a high variability short line category and a low variability long line category. Then pigeons were tested with lines intermediate in length to the two training categories. If category variability is important then the majority of intermediate lines should be categorized into the more variable category, whereas if perceptual similarity is important each intermediate line should be categorized into the category that it most resembles. Pigeons categorized the intermediate test stimuli based on perceptual similarity. 
P43 Matthew Murphy & Robert Cook (Tufts University)
Control by Absolute and Relational Properties in an Auditory Discrimination Task in Pigeons (Columba livia)
Many discrimination tasks typically separate stimuli by absolute or relational properties (i.e. same versus different). In this study, both sources of control were simultaneously available to examine when and how each property controlled behavior. Pigeons (n=4) were reinforced in a go / no-go successive auditory discrimination task for “different” tone stimuli from one stimulus set (octave 1), but not for “different” stimuli from the another set (octave 2) or “same” stimuli from either set. A second experiment tested the same task with two stimulus sets of alternating notes from within a single octave. The response pattern across conditions suggested strong absolute discrimination in the first task. Initial second task results showed relational factor utilization. This indicates that relational factors may spontaneously play a role in audition when absolute factors become less discriminable.
P44 Jennifer J. Pokorny & Frans B.M. de Waal (Living Links, Yerkes National Primate Research Center, Emory University)
Failure of Capuchin Monkeys to Generalize the Oddity Task Under Certain Conditions
Previous work has shown that brown capuchin monkeys (Cebus apella) are able to perform oddity tasks and successfully transfer to new stimuli. However, most of the studies used a WGTA with physical objects of a similar type. We trained 6 capuchin monkeys to perform the oddity task by selecting digital images on a touchscreen computer. Under certain conditions it appeared that the oddity concept was obtained (reached and maintained criterion for at least 2 sessions). However, after subsequent transfer to new digital stimuli types (e.g. clip art, faces), it was found that performance returned to chance level, suggesting that knowledge of the concept failed to generalize. Other strategies were employed to facilitate generalization to new stimulus types, which included providing luminance cues and small set sizes. We will present data on individual performance on each stimulus type as well as performance on subsequent transfer tasks.
P45 Deborah E. Racey, Michael E. Young (Southern Illinois University), & Edward A. Wasserman (University of Iowa)
Discriminating Continuous Variability: Evidence for the Finding Differences Model
A visual variability discrimination task using displays of items that varied along a continuous stimulus dimension, color or size, was presented to college students. Display items differed in their relative similarity and also in proximity of similar items, a manipulation included in order to study effects of display organization on variability discrimination. Stimulus displays were arranged in one of five conditions: same, similar-near, similar-far, dissimilar-near, and dissimilar-far.  In near displays the most similar items were adjacent. The data generally followed a systematic ordering of more “different” responses and lower RTs for dissimilar-far displays to more “same” responses and higher RTs for similar-near displays. When similar items were more proximal, judged display variability decreased, an effect that increased with similarity. These findings provide strong support for a recently proposed model of variability discrimination, the Finding Differences Model (Young, Ellefson, & Wasserman, 2003). 
P46 Matching and Non-matching to Sample in Rats with Olfactory Stimuli
Rebecca M. Rayburn-Reeves, Rhiannon Thomas, Laurence L. Miller & Mark Galizio (University of North Carolina at Wilmington)
Six rats were trained to dig in scented sand to obtain food pellets. Digging in a sample stimulus cup produced two comparison stimuli, one with a scent identical to the sample and the other with a different scent. Three rats were reinforced for digging in the comparison cup that matched the sample and three for digging in the non-matching cup with five different odor stimuli. After 25 sessions a new set of five stimuli was introduced with the same contingency in effect. After 15 sessions with the second stimulus set, a third set was introduced with the contingencies reversed so that rats trained with matching were switched to non-matching and vice versa. All six rats showed acquisition of the initial conditional discriminations, and transfer to the second stimulus set. In contrast, when rats were switched from a matching to a non-matching contingency, there was persistent control by the original contingency.   
P47 Kristin E. Bonnie (Emory University) & Ryan L. Earley (Georgia State University)
Stop, Look and Listen: An Integrative Framework for Social Information Use in Animals 
The field of social learning has been instrumental in shaping our understanding of how, when and why animals utilize the information provided by the behavior of others. Social eavesdropping and public information also have provided insights into social information use among diverse taxa. However, these concepts have not yet been integrated with social learning in any great capacity. We offer a novel, interdisciplinary approach to linking these three concepts, which have remained to date, remarkably distinct within the literature. We identify points of convergence and divergence including types of information gathered (about what versus whom), how information is packaged (signals versus cues) and relative payoffs to parties involved.  Finally, we evaluate the benefits to broadening the scope of research on social information use.  
P48 Jessica Crast, Robin Cooley, & Dorothy Fragaszy (University of Georgia)
Capuchin Monkeys Learn with Others
We investigated the extent to which social context influences skill acquisition in captive young capuchin monkeys. Social groups (adults and juveniles) were presented with an apparatus that could be operated to obtain juice. Concurrently, a matching apparatus was available to juveniles only in a crèche within the home enclosure. Several juveniles used the apparatus in both locations, often in the presence of adults and/or other juveniles. To determine which factors influenced their learning, we compared juveniles that first encountered the apparatus for 20 sessions in the crèche with juveniles that first encountered the apparatus together with proficient adults. We tracked the juveniles’ activity at the apparatus prior to their first solution while alone and while with others. Encountering the apparatus in the presence of adults and other juveniles facilitated the juveniles’ acquisition of the skill compared to prior experience in the crèche.
P49 Colin Ellard (University of Waterloo)
Gerbils Monitor the Behaviour of Conspecifics to Assess Risk.
Previous studies have shown that when gerbils respond to unexpected sensory stimuli by fleeing, their trajectories take into the account the probable behaviour of conspecifics, presumably to avoid competition for safe refuges.  In the present study, gerbils were presented with simulated predators while in an arena that allowed them to view the behaviour of another gerbil.  Responses to predator models depended on the behaviour of observed gerbils.  Observed gerbils that fled from the stimulus facilitated the likelihood of flight in tested gerbils and lack of response in the observed gerbils depressed the likelihood of flight in the tested gerbils.  A second study showed that this dependence was restricted to trials in which the observed gerbils were within visual range of the tested gerbils at stimulus onset.  These findings suggest that gerbils select the appropriate response to unexpected stimuli, in part, by observing the responses of their neighbours.
P50 Tephillah Jeyaraj (University of Georgia)
Response of Pair-housed Male Capuchin Monkeys (Cebus apella) to Inequity.
Brosnan and de Waal (2003) studied the response to unequal rewards of socially-housed female brown capuchin monkeys. The task was to return a token to the experimenter for a reward. Expanding on their study, I tested six male capuchins who have lived in fixed pairs for more than ten years. I used the same procedure with certain modifications to the experimental design and found that pair-housed males did not respond to unequal rewards in the same way as socially-housed females. They responded to inequity by significantly rejecting the low-value reward when both rewards were visible to them but not when they were hidden from view, regardless of whether the competitor received the high-value reward. However, the identity of the competitor did seem to influence rejection of the low-value reward. The monkeys showed significantly more rejection when the competitor receiving the high-value reward was a non-cage-mate rather than their cage-mate.
P51 Jeaniene Leis, Emily Ward, Meredith Bashaw, & Roger K. R. Thompson (Franklin & Marshall College)
Does What a Capuchin Monkey (Cebus apella) Receive Affect His Partner’s Expectation of Reward?
Brosnan and de Waal (2003) reported that Capuchin monkeys (Cebus apella) respond negatively to unequal reward distributions. They interpreted their results as evidence for “an early evolutionary origin of inequity aversion” and a sense of fairness and injustice. They rejected the less anthropomorphic explanation of violated expectations, in which animals forgo a low-value reward if a high-value one is anticipated (i.e. negative contrast). However, Gant, Suri, Disla, & Thompson’s (2004) within-subject finding that Capuchin monkeys valued a cucumber reward less if it was preceded by a grape than preceded by a cucumber supported this latter hypothesis, particularly in the presence of conspecifics. We tested whether or not parallel between-subject contrast effects would occur from one trial to the next if an animal observed a partner receive a grape or cucumber. Our results revealed striking individual differences. All four animals showed between-subject contrast effects, whereas only two showed within-subject contrast effects. 
P52 Kandis Purnell, Ashley Jensen, & Martin Shapiro (California State University, Fresno)
Choice behavior is affected by both the amount and delay of reward.  While most experiments use nutritional rewards, the present set of experiments tested how choice is affected by the amount and delay of a social reward in Siamese fighting fish (Betta splendens).  Male Siamese fighting fish find the access to aggressive displays with another male rewarding.  Using a specially designed plus maze, animals were run in four, 100-trial experiments (half choice and half no-choice trials), with the left and right arm associated with different amounts of time displaying to another male (experiment 1), different delays (experiment 2), and the interaction of amount and delay in self-control designs (experiments 3 and 4).  The results were compared with the most often cited quantitative models dealing with the affects of amount and delay of reward on choice behavior in animals. 
P53 Sanae Okamoto-Barth (Nagoya University and Maastricht University), Nobuyuki Kawai (Nagoya University), Masayuki Tanaka, & Masaki Tomonaga (Primate Research Institute, Kyoto University)
Looking compensates for the distance between mother and infant chimpanzee 
The development of visual interaction between mother and infant has received much attention in developmental and comparative psychology. The present study focused on the question of whether the mother and infant chimpanzee replace physical contact with visual contact. To test this hypothesis, we measured non-synchronous looking (‘looking’) between mother and infant. A unique setting, in which the mother stayed in one location and the infant moved freely, allowed us to analyze the relation between the visual interaction and the distance of a mother-infant pair during the first year of life. Our results showed that ‘looking’ increased when body contact decreased or when the distance between mother and infant increased. We also show a typical “secure-base” behavior, which is characterized by the infant regularly returning to its mother when exploring the environment. These findings imply that attachment between mother and infant chimpanzee appears to develop in a similar fashion as in humans.
P54 Tadd B. Patton and Toru Shimizu (University of South Florida)
Which Features of Female Pigeons Elicit Courtship Display in Males?
Previous research has shown that male pigeons (Columba livia) respond with courtship displays to video images of a female pigeon.  Courtship displays significantly decline when the head region of the female stimulus is occluded, suggesting that this region contains important visual information.  However, the exact features necessary to elicit males’ displays are still unknown.  This study examined the courtship behavior of male pigeons when exposed to a digitally altered female pigeon.  The alterations included size and spatial arrangement of facial features (eyes and beak) as well as the contour (outline) of the bird.  The results showed that the presence of facial features was important only when the contour was not clear and that size and spatial arrangement was not essential to elicit courtship displays.  These findings will be discussed in the context of conspecific recognition and mate selection.
P55 Regina Paxton & Peter Judge (Bucknell University)
Capuchin monkeys (Cebus apella) categorize images of familiar individuals but not unfamiliar individuals
Primates are highly social animals, yet few studies have used social stimuli to investigate their conceptual abilities.  We explored the ability of capuchin monkeys to form a social concept by requiring them to categorize images of conspecifics into one of two sets, "familiar monkeys" (from the subjects' home group) or "unfamiliar monkeys" (previously unseen). Digital photographs of capuchins were presented in a match to sample design. Subjects were required to match the sample image to one of a different monkey from the same familiarity set. The monkeys were able to match images of familiar animals but not images of unfamiliar animals. Our findings are consistent with previous studies showing that primates more easily categorize items into closed sets with a finite number of known elements, as would be the case with the members of their home group, than into open sets such as that defined by "unfamiliar monkeys."
P56 Daniel R. Saunders & Nikolaus F. Troje (Queen's University)
Animal courtship in many species is not only an evaluation process, but also a two-way communicative interaction. Although pigeon courtship has been extensively described, it is not known whether male and female pigeons coordinate their body movements as a form of communication. We used simultaneous motion capture recordings of both partners during courtship to examine correlations between kinematic measurements reflecting behaviors at several different time scales. The behaviors included head bobbing, movement speed, body orientation, and direction of turning. Each was modeled using semi-markov processes previously used for modeling parallel streams of human nonverbal behaviors during conversation. The analysis results in a quantitative ethogram of the choreography of pigeon courtship and elucidates the different levels of coordination, as well as the role of leading, following, and behavioral synchronization between the two partners.
P57 Kandis Purnell, Ashley Jensen, & Martin Shapiro (California State University, Fresno)
Choice behavior is affected by both the amount and delay of reward.  While most experiments use nutritional rewards, the present set of experiments tested how choice is affected by the amount and delay of a social reward in Siamese fighting fish (Betta splendens).  Male Siamese fighting fish find the access to aggressive displays with another male rewarding.  Using a specially designed plus maze, animals were run in four, 100-trial experiments (half choice and half no-choice trials), with the left and right arm associated with different amounts of time displaying to another male (experiment 1), different delays (experiment 2), and the interaction of amount and delay in self-control designs (experiments 3 and 4).  The results were compared with the most often cited quantitative models dealing with the affects of amount and delay of reward on choice behavior in animals. 
P58 Dana J. Gant & Roger K. R. Thompson (Franklin & Marshall College)
Scratch & Match Revisited: A Test of Observational Learning in Pigeons (Columba livia)
Observational learning of a matching/oddity task by pigeons was tested using a gravel-digging procedure with which Wright and Delius (1994) reported significantly faster acquisition by birds as compared to those tested in traditional key-peck tasks. 16 birds were assigned to the following conditions: Observed or unobserved (acquisition-alone) during matching or oddity acquisition trials; observers of learners; observers of experts (i.e., acquisition-alone birds that had reached criterion); and observers of ghost trials (i.e., trials where rewards were revealed by gravel displaced with air-puffs). Although birds in all conditions reached a performance criterion of 75% or better within 16-32 trials, there was no evidence that acquisition of matching or oddity by birds was facilitated within any observational condition. However, consistent with Wright & Delius’ (2005) results, oddity-learning birds made fewer errors across all conditions. 
P59 Ruey K. Cheng, Christina L. Williams, & Warren H. Meck (Duke University)
Effects of prenatal choline supplementation and reinforcement density on temporal precision in peak-interval procedure.
Steady-state performance in the peak-interval (PI) procedure can be characterized by a low–high–low response rate function, which contributes to an approximate Gaussian-shaped mean function centered around the criterion time.  Adult offspring of pregnant rats fed 4.5 times the choline in standard chow can show sharper PI functions than offspring of pregnant rats fed a control diet, indicating greater temporal precision for prenatal choline supplemented rats.  The present study investigated when this precision-enhancing effect emerges by monitoring the temporal control of behavior from the initial acquisition of a fixed-interval (FI) 18-s procedure to acquiring the full Gaussian-shaped response function of the PI 18-s procedure.  The data indicate that the density of reinforcement as determined by the percentage of FI and probe trial interacts with the availability of choline during prenatal development in order to determine the level of timing precision.
P60 Christopher J. MacDonald, Ruey K. Cheng, Elizabeth L. Clore, & Warren H. Meck (Duke Univeristy)
De Novo Protein Synthesis in the Ventral Striatum is Necessary for the Acquisition of a New Temporal Criterion
Rats were trained on the peak-interval procedure using a 20-s temporal criterion (PI-20 s). Following sufficient training, the rats were divided into two groups that differed with respect to whether bilateral cannulae were implanted in the dorsolateral striatum (DS) or ventral striatum (VS). Following surgery, both the DS and VS groups were further subdivided into two groups, which distinguished whether anisomycin (ANI- 62.5 µg/µl)—a protein synthesis inhibitor— or vehicle would be microinjected prior to sessions during a final "transition phase". During this transition phase, all four groups were placed on a PI-50 s procedure so that the rats acquired a new temporal criterion. ANI differentially impaired acquisition with respect to the DS and VS. Although protein synthesis in the VS was necessary to make a transition to the new temporal criterion, it was not necessary to extinguish the S2 response threshold.
P61 Christopher J. MacDonald, Ruey K. Cheng, Antonia M. Laino, & Warren H. Meck (Duke University)
Dissociable Roles for De Novo Protein Synthesis in the Dorsal and Ventral Striatum for Learning When to “Start” and “Stop” Responding
In peak-interval (PI) procedures, animals make abrupt transitions both into and out of a high response state, during which a relatively constant rate of responding centered around the criterion time is observed. These transition times are called the S1 and S2 respectively. Because the S2 is acquired during the earliest PI training sessions in which unreinforced probe trials are first presented, we wondered whether S2 acquisition depends on de novo protein synthesis. Following FI 20-s training, bilateral cannulae were implanted in either the dorsolateral striatum (DS) or ventral striatum (VS) before being placed on the PI training. Anisomycin (ANI- 62.5 µg/µl) – a protein synthesis inhibitor— was microinjected before PI sessions in a sub-set of rats in the DS and VS groups whereas the remaining rats received vehicle solution. While protein synthesis inhibition impaired S2 acquisition in the VS group, temporal accuracy improved in the DS group by sharpening the S1.
P62 Matthew J. Pizzo (University of York) and Jonathon D. Crystal (University of Georgia)
Temporal discrimination of alternate days by rats
The goal of this study was to determine if rats could learn to time a 48-hr interval. Rats (n = 6) were continuously housed in operant chambers in constant darkness. The feeding cycle consisted of unlimited access to food for 6-hr followed by 42 hr without access to food (i.e., meals were available on alternate days). Response rate increased as a function of time prior to the meal; this increase was higher relative to the increase that occurred at the same time of day on alternate (i.e., non-food) days.  These data suggest that rats discriminated alternate days. Next, two meals were omitted to test for the presence of a self-sustained endogenous rhythm. Response rate increased periodically every 24 hr. Implications for alternative mechanisms of time discrimination are discussed.
P63 Kristen E. Pleil, Sara Cordes, Warren H. Meck, & Christina L. Williams (Duke University)
Sex Differences in Counting and Timing: Possible Neuroendocrine Mechanisms
Gonadal hormones have been found to modulate behaviors dependent upon temporal and numerical integration, e.g., spatial navigation, working memory, and motor control.  However, the organizational and activational effects of these hormones on timing and counting abilities have yet to be explored.  In the current study, 2 groups of male (neonatal castrates and adult castrates) and 2 groups of female rats (neonatal estradiol and neonatal oil) were trained on a mixed counting and timing bisection task.  During test sessions, rats were presented with probe trials consisting of intermediate stimulus values. Analyses examined differences in acquisition, precision, and accuracy for both temporal and numerical discriminations.  Results speak to the modulating effects of sex hormones on counting and timing, both during development and in adulthood.  This suggests that sexual dimorphism observed in related behaviors such as spatial navigation may be affected by underlying differences in the organization and activation of gonadal hormones.
P64 Robin L. Cooley, Colin Closek, Sarah Kilgore, & Dorothy Fragasy (University of Georgia)
Capuchins and chimpanzees combine objects and surfaces in manual exploration
Humans modify their manual actions in accord with the physical properties of objects and/or surfaces they explore, and they use objects to explore surfaces.  These characteristics of action are thought to support the development of tool use.  Do nonhuman animals do the same?  We investigated activity in capuchin monkeys (Cebus apella) and chimpanzees (Pan troglodytes) presented with four surfaces (wood, sponge, water, and netting) and two cubes (sponge, wood).  Like human children, (a) both species contacted the surfaces using the objects, and (b) both species differentiated actions combining cubes with different surfaces.  Chimpanzees performed more actions overall and a greater variety of actions combining cubes with surfaces.  The data suggest that both capuchins and chimpanzees spontaneously explore their world in ways supporting the development of goal-directed action with objects (i.e., tool use).    Differences between the genera in exploration match known differences in manual behavior, including tool use, in wild individuals.  
P65 Qing Liu & Dorothy Fragaszy (University of Georgia)
Vigilance in Nut Cracking by Bearded Capuchin Monkeys (Cebus libidinosus)
Visually scanning the environment (vigilance) requires interrupting visual attention for other activities. Capuchin males typically are more vigilant than females, but we know little about the development of vigilance in capuchins. Wild capuchins in our field site in Brazil crack nuts with stones, and they pay close attention to their actions during cycles of striking. They must also be vigilant, as this activity exposes them to predators, and they can be displaced by others. We predict that while cracking nuts, males are more vigilant than females, and adults are more vigilant than juveniles. Video samples of three adult females, three adult males, and four juveniles cracking nuts are coded for frequency and distribution of bouts and duration of time engaged in vigilance. Scoring is still in progress. We will discuss the developmental and ecological implications of our findings.
P67 Kelly A. Schmidtke (Auburn University), Bruce Overmier, & John Holden (University of Minnesota)
Differential Outcomes Procedure Effects on the Ability to Form Equivalent Classes by Pigeons
Humans can spontaneously form equivalent classes, but whether nonhumans can remains controversial. Five pigeons were taught a linear series of three symbolic matching-to-sample discriminations establishing the possibility for the emergence of two stimulus classes via differential reinforcement of each class. The first class (A->B, B->C, C->D) was reinforced with five seconds access to food and the second class (1->2, 2->3, 3->4) was reinforced with one second access to food. Non-reinforced transitivity tests for class formation included examination of two and three nodal distances. Evidence for transitivity in both tests was found. The experiment demonstrates the utility of the Differential Outcomes Procedure for establishing equivalence relations consistent with Sidman's (2000) speculation that reinforcers may become elements that form equivalence classes. Our explanation is based on mediation by conditioned expectancies within the discriminations as the cues for choices (Trapold & Overmier, 1972).