Abstract: When humans are asked to evaluate rewards or outcomes that follow unpleasant (e.g., high-effort) events, they often assign higher value to that reward. This phenomenon has been referred to as cognitive dissonance or justification of effort. There is now evidence that a similar phenomenon can be found in nonhuman animals. When demonstrated in animals, however, it has been attributed to contrast between the unpleasant high effort and the conditioned stimulus for food. In the present experiment, we asked whether an analogous effect could be found in humans under conditions similar to those found in animals. Adult humans were trained to discriminate between shapes that followed a high-effort versus a low-effort response. In test, participants were found to prefer shapes that followed the high-effort response in training. These results suggest the possibility that contrast effects of the sort extensively studied in animals may play a role in cognitive dissonance and other related phenomena in humans.

Abstract: Developmental psychologists have described imitation as a process that suggests perspective-taking abilities. However, imitative behavior has been found in animals, which are generally not considered capable of taking the perspective of another. Previous studies with birds have demonstrated the imitation of a single response (sometimes referred to as action-level imitation). In the present experiment, we examined the extent to which pigeons would imitate an unfamiliar sequence of two behaviors (sometimes referred to as program-level imitation). Our results indicate that, although there are individual differences, pigeons show a significant tendency to match a demonstrated sequence of behavior involving, first, a response to a treadle (pecking at it or stepping on it) and, second, pushing aside a screen that blocks access to food (a left-vs.-right push).

Abstract: Theories of animal timing have had to account for findings that the memory for the duration of a timed interval appears to be dramatically shorted within a short time of its termination. This finding has led to the subjective shortening hypothesis and it has been proposed to account for the poor memory that animals appear to have for the initial portion of a timed interval when a gap is inserted in the to-be-timed signal. It has also been proposed to account for the poor memory for a relatively long interval that has been discriminated from a shorter interval. I suggest here a simpler account in which ambiguity between the gap or retention interval and the intertrial interval results in resetting the clock, rather than forgetting the interval. The ambiguity hypothesis, together with a signal salience mechanism that determines how quickly the clock is reset at the start of the intertrial interval can account for the results of the reported timing experiments that have used the peak procedure. Furthermore, instructional ambiguity rather than memory loss may account for the results of many animal memory experiments that do not involve memory for time.

Abstract: Memory for time by animals appears to undergo a systematic shortening. This so-called choose-short effect can be seen in a conditional temporal discrimination when a delay is inserted between the sample and comparison stimuli. We have proposed that this temporal shortening may result from a procedural artifact in which the delay appears similar to the intertrial interval and thus, produces an inadvertent ambiguity or 'instructional failure'. When this ambiguity is avoided by distinguishing the intertrial interval from the delay, as well as the samples from the delay, the temporal shortening effect and other asymmetries often disappear. By avoiding artifacts that can lead to a misinterpretation of results, we may understand better how animals represent time. An alternative procedure for studying temporal discriminations is with the psychophysical bisection procedure in which following conditional discrimination training, intermediate durations are presented and the point of subjective equality is determined. Research using the bisection procedure has shown that pigeons represent temporal durations not only as their absolute value but also relative to durations from which they must be discriminated. Using this procedure, we have also found that time passes subjectively slower when animals are required to respond to the to-be-timed stimulus.

Abstract: Traditional psychological approaches to animal learning and behavior have involved either the atheoretical behaviorist approach proposed by B. F. Skinner (1938), in which input-output relations are described in response to environmental manipulations, or the theoretical behaviorist approach offered by C. L Hull (1943), in which associations mediated by several hypothetical constructs and intervening variables are formed between stimuli and responses. Recently, the application of a cognitive behaviorist approach to animal learning and behavior has been found to have considerable value as a research tool. This perspective has grown out of E. C. Tolman's cognitive approach to learning in which behavior is mediated by mechanisms that are not directly observable but can be inferred from the results of critical experiments. In the present article, the author presents several examples of the successful application of the cognitive behaviorist approach. In each case, the experiments have been designed to distinguish between more traditional mechanisms and those mediated by hypothesized internal representations. These examples were selected because the evidence suggests that some form of active cognitive organization is needed to account for the behavioral results.