Learning from Animals? Examining the Nature of Human Uniqueness

The Psychological Record -     

Suboptimal choice by dogs: when less is better than more

The less is more effect, an example of an affect heuristic, can be shown in humans when they give greater value to a set of six baseball cards in perfect condition, than to the same set of six perfect cards together with three additional cards each with some value but in fair condition. A similar effect has been reported in monkeys which will eat both grapes and cucumbers but prefer grapes, when they prefer a single grape over a single grape plus a slice of cucumber. In the present experiment, we tested the less is more effect with a nonprimate but social species, dogs. We used dogs that would eat a slice of carrot and a slice of cheese but preferred the cheese. When we then gave them a choice between a slice of cheese and a slice of cheese plus a slice of carrot, most dogs preferred the single slice of cheese. Thus, the less is more effect appears to occur in several species.     

Environmental enrichment affects suboptimal, risky, gambling-like choice by pigeons

Pigeons prefer a risky option with a low probability of a high payoff over a less risky option that results in more food. This finding is analogous to suboptimal human monetary gambling because in both cases there appears to be an overemphasis of the occurrence of the winning event and an underemphasis of the losing event. In the present research, we found that pigeons that were exposed to an enriched environment (a large cage with three other pigeons for 4 h a day) were less likely to show this suboptimal choice behavior compared with typically housed laboratory pigeons in a control group. These results have implications for the mechanisms underlying suboptimal choice by humans (e.g., problem gamblers), and they suggest that a enriched environment may allow for enhanced self-control.     

Suboptimal choice behavior by pigeons

Contrary to the law of effect and optimal foraging theory, pigeons show suboptimal choice behavior by choosing an alternative that provides 20% reinforcement over another that provides 50% reinforcement. They choose the 20% reinforcement alternative—in which 20% of the time, that choice results in a stimulus that always predicts reinforcement, and 80% of the time, it results in another stimulus that predicts its absence—rather than the 50% reinforcement alternative, which results in one of two stimuli, each of which predicts reinforcement 50% of the time. This choice behavior may be related to suboptimal human monetary gambling behavior, because in both cases, the organism overemphasizes the infrequent occurrence of the winning event and underemphasizes the more frequent occurrence of the losing event.     

Relative judgments affect assessments of stimulus duration

Humans were trained on two independent temporal discriminations, with correct choice dependent on the initial stimulus duration. In Experiment 1, the durations were 1.0 and 4.0 sec, with one set of choice stimuli, and 2.0 and 8.0 sec, with a different set of choice stimuli. The 2.0- and 4.0-sec values were selected to be the geometric mean of the two values in the other discrimination. In Experiment 2, the durations were 2.0 and 5.0 sec for one discrimination and 3.5 and 6.5 sec for the other. The 3.5- and 5.0-sec values were selected to be the arithmetic mean of the two values in the other discrimination. In both experiments, participants showed evidence for relational coding of the duration pairs. That is, the test durations were selected to be at the presumed bisection point (i.e., they should have produced indifferent choice), but instead the shorter test duration from the longer duration pair produced a “short” bias (in both experiments), whereas the longer duration from the shorter duration pair produced a “long” bias (in the second experiment). Results were similar to those from Zentall, Weaver, and Clement (2004) with pigeons.     

Reducing Time-Out Assignments for Students with Emotional/Behavioral Disorders in a Self-Contained Classroom

This study assessed the impact of a class-wide time-out/re-directing strategy on (a) the frequency of teacher-assigned time-outs and (b) the time students spent in disciplinary sanctions. Twelve students with emotional/behavioral disorders, enrolled in a self-contained elementary classroom were taught an alternative time-out strategy (Active Response Beads-Time Out), while teachers were taught a re-directing strategy, in an attempt to decrease the amount of student's time spent in time-out (TO) and the number of TO assigned by staff. Using a multiple baseline design across academic classroom periods, results showed that Active Response Beads Time-Out (ARB-TO) and teacher re-directions decreased the total time spent in time-out and number of TO assigned across the three class periods. Results maintained at one, two and four week follow-up sessions.     

Subjective time: cognitive and physical secondary tasks affect timing differently

Humans were trained on a temporal discrimination to make one response when the stimulus duration was short (2 s) and a different response when the stimulus duration was long (8 s). They were then tested with stimulus durations in between to determine the bisection point. In Experiment 1, we examined the effect of a secondary cognitive task (counting backwards by threes) on the bisection point when participants were trained without a cognitive load and were tested with a cognitive load or the reverse (relative to appropriate controls). When the cognitive load increased from training, the psychophysical function plotting long responses against the increase in stimulus duration shifted to the right (as if the internal clock slowed down), and when the cognitive load decreased from training the psychophysical function shifted to the left (as if the internal clock speeded up). In Experiment 2, when the secondary task consisted of exerting continuous force on a transducer (a physically effortful task), it had the opposite effect. When the required force increased from training, the psychophysical function shifted to the left (as if the internal clock speeded up), and when the required force decreased from training, the psychophysical function shifted to the right (as if the internal clock slowed down). The results support an attentional view of the subjective passage of time. A cognitive secondary task appears to decrease attention to temporal cues, resulting in the underestimation of the passage of time, whereas a force requirement appears to increase attention to temporal cues, resulting in the overestimation of the passage of time.     

Sub-Optimal Choice by Pigeons: Failure to Support The Allais Paradox

Pigeons show a preference for an alternative that provides them with discriminative stimuli (sometimes a stimulus that predicts reinforcement and at other times a stimulus that predicts the absence of reinforcement) over an alternative that provides them with nondiscriminative stimuli, even if the nondiscriminative stimulus alternative is associated with 2.5 times as much reinforcement (Stagner & Zentall, 2010). In Experiment 1 we found that the delay to reinforcement associated with the nondiscriminative stimuli could be reduced by almost one half before the pigeons were indifferent between the two alternatives. In Experiment 2 we tested the hypothesis that the preference for the discriminative stimulus alternative resulted from the fact that, like humans, the pigeons were attracted by the stimulus that consistently predicted reinforcement (the Allais paradox). When the probability of reinforcement associated with the discriminative stimulus that predicted reinforcement was reduced from 100% to 80% the pigeons still showed a strong preference for the discriminative stimulus alternative. Thus, under these conditions, the Allais paradox cannot account for the sub-optimal choice behavior shown by pigeons. Instead we propose that sub-optimal choice results from positive contrast between the low expectation of reinforcement associated with the discriminative stimulus alternative and the much higher obtained reinforcement when the stimulus associated with reinforcement appears. We propose that similar processes can account for sub-optimal gambling behavior by humans.     

Categorization,concept learning,and behavior analysis: an introduction

Categorization and concept learning encompass some of the most important aspects of behavior, but historically they have not been central topics in the experimental analysis of behavior. To introduce this special issue of the Journal of the Experimental Analysis of Behavior (JEAB), we define key terms; distinguish between the study of concepts and the study of concept learning; describe three types of concept learning characterized by the stimulus classes they yield; and briefly identify several other themes (e.g., quantitative modeling and ties to language) that appear in the literature. As the special issue demonstrates, a surprising amount and diversity of work is being conducted that either represents a behavior-analytic perspective or can inform or constructively challenge this perspective.     

Selective attention in animal discrimination learning

The traditional approach to the study of selective attention in animal discrimination learning has been to ask if animals are capable of the central selective processing of stimuli, such that certain aspects of the discriminative stimuli are partially or wholly ignored while their relationships to each other, or other relevant stimuli, are processed. A notable characteristic of this research has been that procedures involve the acquisition of discriminations, and the issue of concern is whether learning is selectively determined by the stimulus dimension defined by the discriminative stimuli. Although there is support for this kind of selective attention, in many cases, simpler nonattentional accounts are sufficient to explain the results. An alternative approach involves procedures more similar to those used in human information-processing research. When selective attention is studied in humans, it generally involves the steady state performance of tasks for which there is limited time allowed for stimulus input and a relatively large amount of relevant information to be processed; thus, attention must be selective or divided. When this approach is applied to animals and alternative accounts have been ruled out, stronger evidence for selective or divided attention in animals has been found. Similar processes are thought to be involved when animals search more natural environments for targets. Finally, an attempt is made to distinguish these top-down attentional processes from more automatic preattentional processes that have been studied in humans and other animals.