Imitative learning in Japanese quail (Coturnix japonica) using the bidirectional control procedure

In the bidirectional control procedure, observers are exposed to a conspecific demonstrator responding to a manipulandum in one of two directions (e.g., left vs. right). This procedure controls for socially mediated effects (the mere presence of a conspecific) and stimulus enhancement (attention drawn to a manipulandum by its movement), and it has the added advantage of being symmetrical (the two different responses are similar in topography). Imitative learning is demonstrated when the observers make the response in the direction that they observed it being made. Recently, however, it has been suggested that when such evidence is found with a predominantly olfactory animal, such as the rat, it may result artifactually from odor cues left on one side of the manipulandum by the demonstrator. In the present experiment, we found that Japanese quail, for which odor cues are not likely to play a role, also showed significant correspondence between the direction in which the demonstrator and the observer push a screen to gain access to reward. Furthermore, control quail that observed the screen move, when the movement of the screen was not produced by the demonstrator, did not show similar correspondence between the direction of screen movement observed and that performed by the observer. Thus, with the appropriate control, the bidirectional procedure appears to be useful for studying imitation in avian species.     

The Monty Hall dilemma in pigeons: Effect of investment in initial choice

In the Monty Hall dilemma, humans are initially given a choice among three alternatives, one of which has a hidden prize. After choosing, but before it is revealed whether they have won the prize, they are shown that one of the remaining alternatives does not have the prize. They are then asked whether they want to stay with their original choice or switch to the remaining alternative. Although switching results in obtaining the prize two thirds of the time, humans consistently fail to adopt the optimal strategy of switching even after considerable training. Interestingly, there is evidence that pigeons show more optimal switching performance with this task than humans. Because humans often view even random choices already made as being more valuable than choices not made, we reasoned that if pigeons made a greater investment, it might produce an endowment or ownership effect resulting in more human-like suboptimal performance. On the other hand, the greater investment in the initial choice by the pigeons might facilitate switching behavior by helping them to better discriminate their staying versus switching behavior. In Experiment 1, we examined the effect of requiring pigeons to make a greater investment in their initial choice (20 pecks rather than the usual 1 peck). We found that the increased response requirement facilitated acquisition of the switching response. In Experiment 2, we showed that facilitation of switching due to the increased response requirement did not result from extinction of responding to the initially chosen location.     

Sub-optimal choice in pigeons does not depend on avoidance of the stimulus associated with the absence of reinforcement

When pigeons are given a choice between two alternatives, one leading to a stimulus 20% of the time that always signals reinforcement (S+) or another stimulus 80% of the time that signals no reinforcement (S−), and the other alternative leading to one of two stimuli each signaling reinforcement 50% of the time, they show a strong preference for the first alternative. This preference occurs in spite of the fact that, overall, the second alternative provides two and a half times more reinforcement than the first. In the present experiment we tested the hypothesis that the S− is a less effective conditioned inhibitor because as soon as it is recognized, the pigeon may orient away from it, whereas it does not orient away from the other signals. To test this hypothesis, for Group HLS−, we made the S− more salient and less avoidable by using a ceiling mounted houselight. To control for a possible aversion to the houselight we included Group HLS+, a group for which the houselight served as the S+. And the preferences of both groups were compared to those of a standard no houselight group. The pigeons in all three groups showed a strong preference for the lower probability of reinforcement alternative. Thus, reduced peripheral orienting during presentation of the S− stimulus was not likely responsible for pigeons’ sub-optimal choice.     

A critical eye: Praise directed toward traits increases children’s eye fixations on errors and decreases motivation

Although there is evidence that praise of different types (i.e., generic vs. nongeneric) influences motivation, it is unclear how this occurs. Generic praise (e.g., ??You are smart??) conveys that a child possesses a trait responsible for their performance, whereas nongeneric praise (e.g., ??You worked hard??) conveys that performance is effort-based. Because praise conveys the basis for success, praise may change the interpretation and salience of errors. Specifically, generic praise may highlight the threatening nature of error (i.e., the child does not possess this trait). Because attention is drawn to threats in the environment, we expected generic praise to increase attention to error. We used eyetracking to measure implicit responses to errors (i.e., visual attention: fixation counts and durations) in order to determine the relation between visual attention and verbal reports of motivation (persistence and self-evaluations) in 30 four- to seven-year-old children. Children first saw pictures attributed to them, for which they received either generic or nongeneric praise. The children then saw pictures attributed to them that contained errors??that is, missing features. As a pretest and posttest, the children saw pictures that were ??drawn by other children,?? half of which contained errors. The results indicated that children who received generic praise (??you are a good drawer??) produced more and longer fixations on errors, both their ??own?? and on ??other children??s,?? than did children who received nongeneric praise (??you did a good job drawing??). More fixations on errors were related to lower persistence and lower self-evaluations. These results suggest that generic praise increases attention to errors because error threatens the possession of a positive trait.     

Repeated cocaine experience facilitates sucrose-reinforced operant responding in enriched and isolated rats

The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30) prior to and after 10 days of exposure to cocaine (15 mg/kg, i.p.) or saline was compared. Regardless of rearing condition, rats repeatedly exposed to cocaine had shorter reacquisition latencies to complete a sucrose-reinforced FR 30 task than saline controls. The results suggest that cocaine exposure may have cross-sensitized both EC and IC rats to the reinforcing effects of sucrose or sucrose-associated cues, thus facilitating reacquisition of operant responding.     

Pigeons’ Performances of a Radial-Arm-Maze Analog Task: Effect of Spatial Distinctiveness

The Psychological Record - Pigeons were presented with a radial-arm-maze analog task involving five response keys in one of four spatial arrangements. Two of the arrangements involved...     

Evidence for detection of one duration sample and default responding to other duration samples by pigeons may result from an artifact of retention-test ambiguity

S. C. Gaitan and J. T. Wixted (2000) proposed that when pigeons are trained on a conditional discrimination to associate 1 duration sample with 1 comparison and 2 other duration samples with a 2nd comparison, they detect only the single duration, and on trials involving either of the 2 other duration samples, they respond to the other comparison by default. In 2 experiments, the authors show instead that pigeons lend to treat the retention intervals (such as those used by Gaitan and Wixted) as intertrial intervals, and thus, they tend to treat all trials with a delay as 0-s sample trials. The authors tested this hypothesis by showing that divergent retention functions do not appear when the retention interval is discriminably different from the intertrial interval.     

Imitation and affordance learning by pigeons (Columba livia)

The bidirectional control procedure was used to determine whether pigeons (Columba livia) would imitate a demonstrator that pushed a sliding screen for food. One group of observers saw a trained demonstrator push a sliding screen door with its beak (imitation group), whereas 2 other groups watched the screen move independently (possibly learning how the environment works) with a conspecific either present (affordance learning with social facilitation) or absent (affordance learning alone). A 4th group could not see the screen being pushed (sound and odor control). Imitation was evidenced by the finding that pigeons that saw a demonstrator push the screen made a higher proportion of matching screen pushes than observers in 2 appropriate control conditions. Further, observers that watched a screen move without a demonstrator present made a significantly higher proportion of matching screen pushes than would be expected by chance. Thus, these pigeons were capable of affordance learning.     

Perceptual learning in pigeons: Decreased ability to Discriminate samples mapped onto the same comparison in many-to-one matching

Humans often treat two stimuli that are associated with a common response as similar in other contexts. They do so presumably because those stimuli become conceptually or perceptually more similar to each other (perceptual learning). An analogous phenomenon may occur in pigeons when they are trained with a matching-to-sample procedure in which more than one sample is mapped onto the same comparison. In the present research, pigeons were trained to select one comparison following either of two samples (S₁ or S₂) and to select the other comparison following either of two different samples (S₃ or S₄). When the samples were then presented as positive and negative stimuli in a simple successive discrimination, samples that had been associated with the same comparison during original training (e.g., S₁ vs. S₂) were more difficult to discriminate than were samples that had been associated with different comparisons (e.g., S₁ vs. S₃). Thus, it appears that perceptual learning occurs in pigeons as well.