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Cooperative behavior represents a situation in which individuals sometimes act in a way that produces a gain to another at a cost to themselves. This may be explained by a history of repeated interactions with others in which such behavior has resulted in reciprocal cooperation from others. Sometimes, even with reciprocal cooperation, gains and costs are unbalanced between partners. In this case, there is evidence that people may present an aversion to both disadvantageous and advantageous distributions of gains. In other words, they may act in such a way as to ensure an equal outcome among all group members. Aversion to inequity that benefits oneself (advantageous inequity (AI) aversion) may be more dependent on social and cultural cues than aversion to inequity that benefits others (disadvantageous inequity (DI) aversion). Using both between-subjects (Experiment 1) and within-subjects (Experiment 2) manipulations, the influence of recent experience with AI on participants' willingness to produce DI was explored within the context of a two-player card game. In initial game phases, the percentage of trials in which the participant experienced AI was manipulated. In subsequent game phases, participants had the opportunity to produce DI to themselves. The results from both experiments suggest that aversion to DI is reduced by recent experience with AI. This procedure allows social influences on DI to be tested, which may be important for providing a psychological explanation of cultural differences in aversion to DI. [ABSTRACT FROM AUTHOR]

Serial reversal-learning procedures are simple preparations that allow for a better understanding of how animals learn about environmental changes, including flexibly shifting responding to adapt to changing reinforcement contingencies. The present study examined serial reversal learning with humans by arranging both midsession and variable contingency reversals across two experiments. We also examined the effects of extinction by adding nonreinforced trials at the end of later sessions and provided the first evaluation of effects of win-stay/lose-shift versus counting strategies on accuracy and response latency of humans' reversal-learning performance. In each experiment, responding tracked contingency reversals, primarily with participants using either win-stay/lose-shift or counting strategies. Introducing variable reversal points in the second experiment resulted in near-exclusive win-stay/lose-shift responding among participants and eliminated counting of trials. Each experiment also revealed an immediate shift from S2 to S1 after experiencing extinction during the initial test trial, indicating resurgence of the initial response through a win-stay/lose-shift response pattern. Therefore, the present study replicates and extends prior findings of a win-stay/lose shift response pattern in situations of greater uncertainty. These findings suggest that differences in environmental certainty induce qualitatively different decision-making strategies. [ABSTRACT FROM AUTHOR]

Three experiments examined human rates and patterns of responding during exposure to various schedules of reinforcement with or without a concurrent task. In the presence of the concurrent task, performances were similar to those typically noted for nonhumans. Overall response rates were higher on medium-sized ratio schedules than on smaller or larger ratio schedules (Experiment 1), on interval schedules with shorter than longer values (Experiment 2), and on ratio compared with interval schedules with the same rate of reinforcement (Experiment 3). Moreover, bout-initiation responses were more susceptible to influence by rates of reinforcement than were within-bout responses across all experiments. In contrast, in the absence of a concurrent task, human schedule performance did not always display characteristics of nonhuman performance, but tended to be related to the relationship between rates of responding and reinforcement (feedback function), irrespective of the schedule of reinforcement employed. This was also true of within-bout responding, but not bout-initiations, which were not affected by the presence of a concurrent task. These data suggest the existence of two strategies for human responding on free-operant schedules, relatively mechanistic ones that apply to bout-initiation, and relatively explicit ones, that tend to apply to within-bout responding, and dominate human performance when other demands are not made on resources. [ABSTRACT FROM AUTHOR]

Many studies have shown that pigeons will sometimes behave suboptimally by choosing an option that provides food less frequently over one that provides food more frequently. The critical factor in driving suboptimal behavior in these procedures is that the delayed outcomes are differentially signaled on the suboptimal alternative, but not the optimal alternative. Although this procedure is frequently cited as potentially analogous to human gambling, there is little empirical data to evaluate this assertion. The present study tested both pigeon (Experiment 1) and human (Experiment 2) subjects with a suboptimal choice task. Subjects chose between a suboptimal alternative that provided a large reinforcer 20% of the time and an optimal alternative that always provided a small reinforcer. Stimuli presented during the delays signaled the outcomes on the suboptimal alternative in some conditions. When outcomes were signaled, pigeons chose the suboptimal alternative more frequently than did humans. When the outcomes were not signaled, pigeons' choices became more optimal, but humans' choices did not. Humans' suboptimal choice was unrelated to performance on a probability discounting task. Overall, these findings suggest that although both pigeons and humans can choose suboptimally, more research is needed in order to determine whether non-human performance on this task can serve as a model for human gambling. [ABSTRACT FROM AUTHOR]

Five decades ago, Dmitry Belyaev, Lyudmila Trut, and colleagues began a now-famous experiment, selectively breeding foxes based on one criterion: perceived tame behavior. Over generations, the fox population changed in behavior (as predicted) but, intriguingly, also changed markedly in appearance—for example, many had wider mouths, curlier tails, different fur coloring, and floppy ears. These researchers concluded that the morphological changes that appeared in their foxes were a by-product of the researchers’ selecting for genetic variants that are implicated both in behavior and in appearance. For decades, scientists have largely accepted this “shared genetic variants” interpretation to fully account for the co-occurrence of behavioral and morphological phenotypes in these foxes and in other domesticated animals. However, several decades of psychological research on human social cognition, human-canine interaction, and canine behavior strongly suggest that such an account may be incomplete. I forward a supplementary perspective, based on psychological research, that the covariation of appearance and behavior among these foxes may be partly an artifact of human psychological processes at play in selection. These processes include humans’ tendency to infer individuals’ traits based on their physical features; trait inferences, in turn, influence how humans treat those individuals. If accurate, this account bears on our understanding of these famous foxes, human-canine interactions, as well as humans’ role in domestication. [ABSTRACT FROM AUTHOR]

In three experiments, we investigated the contextual control of attention in human discrimination learning. In each experiment, participants initially received discrimination training in which the cues from Dimension A were relevant in Context 1 but irrelevant in Context 2, whereas the cues from Dimension B were irrelevant in Context 1 but relevant in Context 2. In Experiment 1, the same cues from each dimension were used in Contexts 1 and 2, whereas in Experiments 2 and 3, the cues from each dimension were changed across contexts. In each experiment, participants were subsequently shifted to a transfer discrimination involving novel cues from either dimension, to assess the contextual control of attention. In Experiment 1, measures of eye gaze during the transfer discrimination revealed that Dimension A received more attention than Dimension B in Context 1, whereas the reverse occurred in Context 2. Corresponding results indicating the contextual control of attention were found in Experiments 2 and 3, in which we used the speed of learning (associability) as an indirect marker of learned attentional changes. Implications of our results for current theories of learning and attention are discussed. [ABSTRACT FROM AUTHOR]

Four experiments in human instrumental learning explored the associations involving the context that develop after three trials of training on simple discriminations. Experiments 1 and 4 found a deleterious effect of switching the learning context that cannot be explained by the context-outcome binary associations commonly used to explain context-switch effects after short training in human predictive learning and in animal Pavlovian conditioning. Evidence for context-outcome (Experiment 2), context-discriminative stimulus (Experiment 3), and context-instrumental response (Experiment 4) binary associations was found within the same training paradigm, suggesting that contexts became associated with all the elements of the situation, regardless of whether those associations played a role in a specific context-switch effect detected on performance. [ABSTRACT FROM AUTHOR]

Humans responded on multiple random-ratio (RR) random-interval (RI) schedules, and their verbalized performance awareness (PA; i.e., their ability to accurately describe what they did) was measured in three experiments. In Experiment 1, instructions informed participants that to earn points, either sometimes rapid responding and sometimes slow responding would work best (accurate instructions); rapid responding would work best ( go fast instructions); spaced responding would work best ( go slow instructions); or no advice was provided (minimal instructions). In Experiments 2 and 3, participants received either accurate or minimal instructions and were subject to extinction after a multiple RR-RI schedule. In all experiments, both performance awareness, and receiving accurate instructions, were related to schedule-sensitive responding, but were unrelated to one another - participants receiving accurate-rate instructions were not more likely to show performance awareness than those exposed to minimal instructions. Both higher performance awareness and exposure to accurate instructions predicted faster extinction in Experiment 2 but not in Experiment 3. The current results suggest that performance awareness rather than contingency awareness is more strongly related to humans displaying schedule-typical behavior and that this is not strongly related to any explicit verbal instructions that are given. [ABSTRACT FROM AUTHOR]

Two experiments examined the impact of response-independent outcome delivery on human rates of response and judgments of control in an instrumental conditioning task. In Experiment 1, when participants responded on a schedule with a relatively high probability of a response producing an outcome, a random ratio (RR-5), judgments of control declined as rates of response-independent outcomes increased. However, when response-dependent outcomes were delivered with a relatively low probability (RR-15), increasing the rate of response-independent outcomes increased rates of response and judgments of control. Experiment 2 replicated this effect, but also noted a differential effect of response-independent outcome and response-independent sensory presentations on response rate and judgments of causal effectiveness. Ratings of the context in which the conditioning occurred suggested these were correlated with total outcome presentation, and that the role of context on response rate and judgments of control may be important to consider. [ABSTRACT FROM AUTHOR]

In two experiments, we examined the effect of modifications to the features of a stick-and-tube problem on the stick lengths that adult humans used to solve the problem. In Experiment 1, we examined whether people's tool preferences for retrieving an out-of-reach object in a tube might more closely resemble those reported with laboratory crows if people could modify a single stick to an ideal length to solve the problem. Contrary to when adult humans have selected a tool from a set of ten sticks, asking people to modify a single stick to retrieve an object did not generally result in a stick whose length was related to the object's distance. Consistent with the prior research, though, the working length of the stick was related to the object's distance. In Experiment 2, we examined the effect of increasing the scale of the stick-and-tube problem on people's tool preferences. Increasing the scale of the task influenced people to select relatively shorter tools than had selected in previous studies. Although the causal structures of the tasks used in the two experiments were identical, their results were not. This underscores the necessity of studying physical cognition in relation to a particular causal structure by using a variety of tasks and methods. [ABSTRACT FROM AUTHOR]

In an up-linkage replication, three experiments examined adult humans' folk physics, i.e., their naturally occurring and spontaneous understanding of the physical world, using a violation of expectation (VOE) task and stimuli similar to those used to study chimpanzees', monkeys', and rooks' folk physics. Unlike what has been reported with nonhuman primates, adult humans did not look longer at physically impossible than possible events, though they did rate the physically impossible events as more interesting and novel than the possible events. These results underscore that behavior during a VOE experiment has many possible causes, only one of which may be a subject's folk physics. [ABSTRACT FROM AUTHOR]

Simultaneous protocols typically yield poorer stimulus equivalence outcomes than do other protocols commonly used in equivalence research. Two independent groups of three 3-member equivalence sets of stimuli were used in conditional discrimination procedures in two conditions, one using the standard simultaneous protocol and the other using a hybrid simultaneous training and simple-to-complex testing. Participants completed the two conditions in one long session in Experiment 1, but in separate sessions in Experiment 2. The same stimulus sets used in Experiment 1 were randomized for the two conditions in Experiment 2. Overall, accuracy was better with the hybrid than with the standard protocol in both experiments. The equivalence yield was also better under the hybrid than under the standard protocol in each experiment. The results suggest that the order of testing for emergent relations may account for the difficulty often encountered with the standard simultaneous protocol. [ABSTRACT FROM AUTHOR]

Previous studies have identified potential sources of competing stimulus control in tests for stimulus equivalence. The present experiment employed the Nintendo Wii remote (Wiimote®) to investigate whether such competition would affect suboperant action dynamics (e.g., topographies of equivalence responses). Following one-to-many training on conditional discriminations sufficient to establish three 3-member equivalence classes, participants were presented with a test for equivalence responding that included five different trial types. These included 'traditional' equivalence trials, on which the incorrect stimulus had previously been presented as a correct comparison stimulus during training, trials on which a novel unrelated word was provided as the incorrect comparison, and trials on which the incorrect stimulus varied in orthographical and phonological similarity to the sample stimulus. The presence of phonological and orthographic distractor stimuli significantly reduced the probability of equivalence-consistent responding, relative to neutral distractors, but this effect was almost exclusively seen in participants who failed to demonstrate equivalence on traditional equivalence trials. Analyses of correct response trajectories suggested that the prior history of reinforcement for choosing the incorrect stimulus on the traditional equivalence trial gave rise to greater competition than did phonological or orthographic similarity between the sample and incorrect comparisons. [ABSTRACT FROM AUTHOR]

The present study examined the role of derived relations in the generalizability of the evaluative conditioning effect. Healthy university students participated. Four geometrical shapes were first established as discriminative stimuli for the contingent presentation of pictograms (B1, B2, C1, and C2, respectively). We then assessed the reinforcing properties of B1 versus B2, and C1 versus C2 by using simultaneous discrimination tasks: at baseline (baseline assessment), after pairing B1 with aversive slides plus noise and B2 with pleasant slides (test I), and after employing equivalence training and testing to establish B1 as equivalent to C1 and B2 as equivalent to C2 (test II). Most participants (82 %) in the experimental condition, as compared with the control conditions (17 % and 10 %), selected the discriminative shapes for B2 (test I) and C2 (test II) on most trials, replicating and extending previous findings. Subsequently, the geometrical shapes were established as equivalent to the letters X, Y, W, and Z, respectively, which then served as antecedent stimuli in simultaneous discrimination tasks as before (test III). As was expected, only participants in the experimental condition showed preference for the novel letters that were established as equivalent to B2-producing and C2-producing shapes. These findings suggest that the evaluative conditioning effect may extend far beyond the stimulus being de/valuated and narrow the behavioral repertoire. [ABSTRACT FROM AUTHOR]

The goal of the present study was to evaluate the role of verbal stimuli in the production of response variability in humans. College students were distributed into three groups and asked to type three-digit sequences. Participants in the systematic group were instructed to produce sequences according to a rule of their choice; those in the random group were instructed to produce sequences according to chance; and those in the control group were not instructed about how to produce sequences. The experiment employed an ABA design. During the A phases, low-frequent sequences were reinforced (variability contingency), whereas during the B phase, reinforcement was withdrawn (extinction). The results indicated the following: (1) The instructions were efficient at producing systematic and random-like patterns for the systematic and random groups, respectively; in the absence of instructions, a mix of both patterns was observed. (2) Behavior was sensitive to extinction independently of the instructions provided. (3) Systematic patterns favored a more equiprobable distribution of sequences across trials. (4) Reaction times were longer for responding in a systematic than in a random-like fashion. The present findings suggest that individual differences in meeting variability contingencies may be due, at least partially, to instructional control. [ABSTRACT FROM AUTHOR]

The aim of this study was to delineate the minimal conditions for extinction of Pavlovian modulation in humans. Previous experiments at our lab showed that, after X ➔ A+/A- acquisition training, X- trials did not extinguish differential X ➔ A+/A- responding, while X ➔ A- trials did. Additionally, X ➔ A- extinction training seemed only to extinguish differential X ➔ A+/A- responding, while leaving differential responding on a concurrently trained Y ➔ B+/B- discrimination intact. It thus seemed that the X ➔ A+/A- discrimination can only be extinguished by X ➔ A- extinction trials. (Rescorla, Journal of Experimental Psychology: Animal Behavior Processes 12, 16-24, ), on the other hand, found that the minimal conditions for extinction were broader in pigeons: Namely, he found that an acquired X ➔ A+/A- discrimination could be extinguished by presenting the original feature X in combination with a different target (B) that was minimally trained as an exciter. We thus wanted to examine whether this was also the case in humans. We found that nonreinforced X ➔ B- presentations did not abolish discriminative X ➔ A/A responding when target B was a nonreinforced stimulus. Nonreinforced X ➔ B- trials did extinguish the X ➔ A+/A- discrimination when target B had previously been trained as a target for modulation (X ➔ B+/B- or Y ➔ B+/B- training) or as a reinforced exciter (B+). Our results thusf parallel and extend those in nonhuman animals (Rescorla, Journal of Experimental Psychology: Animal Behavior Processes 12, 16-24, ). [ABSTRACT FROM AUTHOR]

Consistent with human gambling behavior but contrary to optimal foraging theory, pigeons show a strong preference for an alternative with low probability and high payoff (a gambling-like alternative) over an alternative with a greater net payoff (Zentall & Stagner, Proceedings of the Royal Society B, 278, 1203-1208, ). In the present research, we asked whether humans would show suboptimal choice on a task involving choices with probabilities similar to those for pigeons. In Experiment 1, when we selected participants on the basis of their self-reported gambling activities, we found a significantly greater choice of the alternative involving low probability and high payoff (gambling-like alternative) than for a group that reported an absence of gambling activity. In Experiment 2, we found that when the inhibiting abilities of typical humans were impaired by a self-regulatory depletion manipulation, they were more likely to choose the gambling-like alternative. Taken together, the results suggest that this task is suitable for the comparative study of suboptimal decision-making behavior and the mechanisms that underlie it. [ABSTRACT FROM AUTHOR]

In this study, we examined whether adult humans' tool selections in a stick-and-tube problem might resemble previously published results of crows' selections if people had more experience solving the problem or were presented with a more ambiguous problem. In Experiments 1a and 1b, when given multiple opportunities to select a stick from a set of 10 to retrieve a candy located either 8 or 16 cm from the opening of a tube, the participants always selected a stick that was long enough to retrieve the candy; however, they did not generally select either the stick whose length matched the object's distance or the longest stick in the set-two outcomes reported in studies with crows. In Experiment 2, participants who were allowed only a brief period of time to study the problem selected a longer stick than did participants allowed unlimited time to do the same. However, only when the candy's distance was 16 cm did these people reliably select the longest stick in the set. It seems that increasing, but not decreasing, people's uncertainty about a problem can make humans' tool selections more similar to those reported with crows. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the degree to which responding would resurge in children diagnosed with Autism Spectrum Disorders (ASD) following an intervening training period comprising different schedules of reinforcement. Twenty-four children of the ages 7-15, with a diagnosis of an ASD, were taught a play a sequence on a variable ratio- (VR) 3 schedule of reinforcement, during a 30-min session. The play sequence was then extinguished before the participants were taught a second play sequence, using a VR-4 schedule for 30 min, a VR-4 schedule for 60 min, or a VR-2 schedule for 30 min. A 5-min extinction session was then conducted to determine the impact that the intervening schedules had on the resurgence of the original behavior. The original sequence resurged to a greater extent for Group VR-4 30 min than it did for the other two groups. The results provide evidence that the length of time between initial training and testing is not a prime determinant of the level of resurgence, but that the amount of conditioning may play a stronger role: The greater the number of reinforcers received, the smaller the resurgence effect. [ABSTRACT FROM AUTHOR]

Pigeons were trained on a two-choice simultaneous discrimination (red vs. green) that reversed midway through each session. After considerable training, they consistently made both anticipatory errors prior to the reversal and perseverative errors after the reversal, suggesting that time (or number of trials) into the session served as a cue for reversal. In Experiment 2, to discourage the use of time as a cue, we varied the location of the reversal point within the session such that it occurred semirandomly after Trial 10, 25, 40, 55, or 70. Pigeons still tended both to anticipate and to perseverate. In Experiment 3, we required 20 pecks to a stimulus on each trial to facilitate memory for the preceding response and sensitivity to local reinforcement contingencies, but the results were similar to those of Experiment 2. We then tested humans on a similar task with a constant (Experiment 4) or variable (Experiment 5) reversal location. When the reversal occurred consistently at the midpoint of the session, humans, like pigeons, showed a tendency to anticipate the reversal; however, they did not show perseverative errors. When the reversal location varied between sessions, unlike pigeons, humans adopted a win-stay/lose-shift strategy, making only a single error on the first trial of the reversal. [ABSTRACT FROM AUTHOR]