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.     

Perspectives on observational learning in animals

Observational learning is presumed to have occurred when an organism copies an improbable action or action outcome that it has observed and the matching behavior cannot be explained by an alternative mechanism. Psychologists have been particularly interested in the form of observational learning known as imitation and in how to distinguish imitation from other processes. To successfully make this distinction, one must disentangle the degree to which behavioral similarity results from (a) predisposed behavior, (b) increased motivation resulting from the presence of another animal, (c) attention drawn to a place or object, (d) learning about the way the environment works, as distinguished from what we think of as (e) imitation (the copying of the demonstrated behavior). Several of the processes that may be involved in observational learning are reviewed, including social facilitation, stimulus enhancement, several kinds of emulation, and various forms of imitation.     

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.     

Longitudinal Assessment of Sleep–Wake Regulation and Attachment Security with Parents

The development of sleep–wake regulation occurs within the context of the infant–parent relationship. The present study investigated (1) patterns of change in night waking across infancy and attachment to parents and (2) if dependency, a characteristic of secure subgroup B4 and insecure‐resistant infants, accounted for differences in night waking. Forty‐six families reported on the number of infant night wakings at 7, 12, and 14 months of age. Attachment was measured at 12 (infant–mother) and 14 (infant–father) months. Findings suggest that infants with a secure (including the dependent‐secure, B4) pattern of attachment with mothers decreased in the number of night wakings over time, whereas infants with an insecure‐resistant pattern of attachment with mothers continued to wake at night into the second year. Attachment dependency did not account for differences in night waking. These findings are important to understanding the mechanism(s) underlying the relation between attachment and sleep–wake regulation. Copyright © 2012 John Wiley & Sons, Ltd.     

Production deficiencies in elicited language but not in the spontaneous verbalizations of hyperactive children

Setting and task conditions were assessed for their effects on the language of hyperactive children. Verbal data were recorded for 22 hyperactive children and 22 elementary-age controls during four storytelling tasks and transitions, and under two conditions of a nonverbal performance task in a counterbalanced order. Findings were that hyperactive children were more spontaneously talkative than their classmates during transitions and nonverbal tasks (nonelicited conditions) but were less talkative when they were asked to tell stories (elicited conditions). These findings and those attributable to the story comparisons were interpreted in line with the optimal stimulation theory, which suggests that minimal stimulus input (delays and nonelicited conditions) precipitate excessive verbal activity from hyperactive children. Production deficiencies, on the other hand, were specific to type of stimulus input to be processed. Stories requiring organization and planning without the external structure or salience of visual cues (a sequence of word cards or pictures) produced production deficiencies.I thank Margo Wilson for her expertise in the development and scoring of the language measures. I am also grateful to Mary Kemper for help with data collection, and to Joe Boggs and Connie Hobbs for their assistance with data analyses.     

Key pecking in pigeons produced by pairing keylight with inaccessible grain

In Experiment I, keylight was paired with inaccessible grain delivery (under two conditions of keylight intensity) to determine if autoshaping would occur in the absence of primary reinforcement. In Experiment II, the procedure was repeated with accessible grain, for comparison. In Experiment III, the procedures were repeated with explicitly unpaired presentations of keylight and either inaccessible or accessible grain. The results indicated that key pecking occurred as quickly in the presence of keylight pairings with inaccessible grain as with accessible grain, though (except for one bird) key pecking was not maintained with inaccessible grain. Furthermore, compared to the dim keylight, the bright keylight greatly suppressed key pecking when paired with inaccessible grain, and reduced the rate of key pecking when paired with accessible grain. Little key pecking occurred in groups exposed to explicitly unpaired presentations of keylight (whether bright or dim) and grain (whether accessible or inaccessible). When the birds in Experiment III were retested with explicitly paired presentations of keylight and grain, little key pecking was observed, suggesting suppressive effects of prior explicitly unpaired presentations. It is suggested that the effects of key-brightness manipulation were produced by the association of grain with cues other than the response key, or by distraction produced by partial illumination of the grain hopper.     

Comparison of two oddity tasks with pigeons

Two oddity tasks were compared: one in which the odd stimulus could appear on any of the three stimulus positions (true oddity); the other in which the odd stimulus could only appear on the left or right but not the center (oddity-from-sample). A stimulus-configuration theory predicts faster oddity-from-sample learning, whereas a theory, based on shifts in observing over trials, predicts faster learning of true oddity. Pigeons learned the oddity-from-sample task faster, thus supporting configuration theory. Performance on the oddity-from-sample task but not the true oddity task was facilitated by increasing the number of responses required to terminate a trial. When the oddity-from-sample pigeons were shifted to the true oddity task, no evidence of positive transfer was found, suggesting that a configuration theory alone is insufficient to explain differences in acquisition. Only when a correction procedure was introduced did the true oddity pigeons perform above 50%.     

Behavioral comparisons of hyperactive and normally active children in natural settings

Matched pairs of hyperactive and normally active children were observed in six natural classroom settings and a number of specific behaviors continuously recorded. Both groups of children showed differences in behavior as a function of settings (selected to vary in amount of external stimulation and structure), but only certain settings differentiated hyperactive from control children. Hyperactive children displayed significantly more noise-vocalization and more disruptive and off-task behavior in the most frequently observed (low stimulation) classroom settings (e.g., seat work). Type of off-task behavior (out-of-seat or visually off-task) depended upon amount of classroom structure (i.e., teacher- vs. self-directed). Results were discussed in terms of their implications for identification and treatment of hyperactive children through the modification of the antecedent conditions of stimulation and structure.     

Control of pigeons' matching-to-sample performance by differential sample response requirements

Pigeons were trained on a matching-to-sample task in which sample hue and required sample-specific observing behavior provided redundant, relevant cues for correct choices. On trials that involved red and yellow hues as comparison stimuli, a fixed-ratio 16 schedule (FR 16) was required to illuminate the comparisons when the sample was red, and a differential-reinforcement-of-low-rates 3-sec schedule (DRL 3-sec) was required when the sample was yellow. On trials involving blue and green hues as comparison stimuli, an FR 16 schedule was required when the sample was blue and a DRL 3-sec schedule was required when the sample was green. For some pigeons, a 0-sec delay intervened between sample offset and comparison onset, whereas other pigeons experienced a random mixture of 0-sec and 2-sec delay trials. Test trial performance at 0-sec delay indicated that sample-specific behavior controlled choice performance considerably more than sample hue did. Test performance was independent of whether original training involved all 0-sec delay trials or a mixture of 0-sec and 2-sec delays. Sample-specific observing response requirements appear to facilitate pigeons' matching-to-sample performance by strengthening associations between the observing response and correct choice.