Constraints on Pavlovian conditioning of the pigeon: Relative conditioned reinforcing effects of red-light and tone CSs paired with food

Recent Pavlovian conditioning experiments presented all possible CS-US combinations of red-light and tone CSs and food and shock USs to separate groups of pigeons. Pigeons receiving shock USs demonstrated conditioned head raising followed by prancing to both CSs, but CRs were acquired more rapidly to tone than to red light. Although pigeons receiving food USs rapidly acquired a conditioned response of pecking to the red-light CS, there was no evidence of conditioned responding in groups receiving tone-food pairings. This outcome left open the possibility that Pavlovian pairings of tone and food may have resulted in association formation that was not revealed in performance. The present series of experiments attempted to reveal that association, using an indirect method of assessment, conditioned reinforcement. Experiment 1 demonstrated that both red light and tone paired with food became positive conditioned reinforcers, suggesting that an association between tone and food was formed in the same number of Pavlovian conditioning trials that previously failed to yield any direct evidence of conditioning. Experiment 2, which presented fewer conditioning trials, revealed that the tone-food association was formed less rapidly than the red light-food association. Experiment 3 demonstrated that the observed outcomes were not attributable to unconditioned, rather than conditioned, reinforcing effects of the Css.     

Turning a penrose triangle inside out

Why do impossible figures, which cannot exist in three dimensions, appear to make threedimensional sense? In order to shed some light on this question the limits may be tested to which three-dimensional operations on these figures can be performed. In this paper a particularly difficult operation, viz., torus eversion is attempted. Not only is an eversion found to be possible but an unfamiliar impossibility develops. The regular form of the eversion is shown to be unique.     

Automatic access of the meanings of ambiguous words in context: Some limitations of knowledge-based processing

Five experiments are described on the processing of ambiguous words in sentences. Two classes of ambiguous words (noun-noun and noun-verb) and two types of context (priming and nonpriming) were investigated using a variable stimulus onset asynchrony (SOA) priming paradigm. Noun-noun ambiguities have two semantically unrelated readings that are nouns (e.g., PEN, ORGAN); noun-verb ambiguities have both noun and verb readings that are unrelated (e.g., TIRE, WATCH). Priming contexts contain a word highly semantically or associatively related to one meaning of the ambiguous word; nonpriming contexts favor one meaning of the word through other types of information (e.g., syntactic or pragmatic). In nonpriming contexts, subjects consistently access multiple meanings of words and select one reading within 200 msec. Lexical priming differentially affects the processing of subsequent noun-noun and noun-verb ambiguities, yielding selective access of meaning only in the former case. The results suggest that meaning access is an automatic process which is unaffected by knowledge-based (“top-down”) processing. Whether selective or multiple access of meaning is observed largely depends on the structure of the ambiguous word, not the nature of the context.     

The development of alertness

Two experiments explored variation in the alerting process across age and warning interval as well as the effects of alertness on subsequent processing. Experiment 1 obtained alertness functions for a group of 5-year-olds, 8-year-olds, and adults. Results revealed strong age differences in speed of alerting and in maintenance of alertness over a 1-sec interval. Five-year-olds alerted more slowly than older groups and sustained optimal alertness less well. Both groups of children showed more variability in alerting functions compared with adults. Experiment 2 examined the degree to which age differences in processing speed were attributable to differential speed and maintenance of alerting. Masking functions obtained across variations in the alerting interval revealed that when level of alertness was optimal in both 5-year-olds and adults, minimal age differences in processing speed were observed. During short, nonoptimal alerting intervals, speed of processing in adults was faster than in 5-year-old children. The pattern of results across studies suggested that alertness can fluctuate over time in young children, that level of alertness affects subsequent perceptual processing speed, and that developmental variation in speed and maintenance of alertness can partly explain observed age differences in processing speed. The potential role of alertness in more complex cognitive tasks is discussed.     

The effects of base rates and individuating information on judgments about another person

Past research suggests that in judging a person's category membership, people largely ignore the population frequency of membership in the category (base rates) in favor of individuating information about the particular person. This study tested the hypothesis that base rates will be utilized to the extent that the usefulness of the individuating information for diagnosing category membership is diminished. Subjects were given problems in which both base rates of membership in each of two categories and individuating information about a target person were presented. Then, in each case, they were asked to assess the probability that the target person belonged to each category. In three sets of problems, the diagnostic usefulness of the individuating information (personality characteristics) was diminished by including individuating information that was either inconsistent or irrelevant, or by increasing the similarity of the two alternative membership categories. In a fourth set of problems, the individualistic information included consistent, relevant personal characteristics and the membership categories were dissimilar. As expected, base rates were used in each of the first three sets of problems but were ignored in the fourth set. The results were interpreted in terms of informational factors that induce a shift away from a habitual, spontaneous reliance on a source of information (e.g., personality traits) for which one has well-developed rules (e.g., intuitive personality theories), and toward a more controlled, deliberate mode of thinking wherein other sources of information (e.g., base rates) are attended to and incorporated into judgment through less frequently used rules (e.g., sampling rules).     

Self-assessment,self-enhancement,and task preference

If task choice depends on a person's interest in the accurate assessment of his or her abilities, task attractiveness should be positively related to the diagnosticities of all performance outcomes with regard to one's ability level. In contrast, the view that people are primarily interested in maximizing pride or mininizing shame would predict that task attractiveness is positively related to the diagnosticity of success but negatively related to the diagnosticity of failure. To test these predictions, subjects were presented with tasks that varied orthogonally in the extent to which success was diagnostic of high ability level and the extent to which failure was diagnostic of low ability level. Consistent with the self-assessment view, task attractiveness increased both with the diagnosticity of success and with the diagnosticity of failure. Furthermore, both effects were more pronounced for high achievement motive subjects than for low achievement motive subjects. This result lends support to the self-assessment view, which assumes that high achievement motive subjects are more interested in attaining the ability-relevant information contained in any performance outcome.     

Children's scales of length and loudness: A developmental application of cross-modal matching

The cross-modal matching techniques that have produced scales of sensory magnitude for a variety of perceptual continua in adults were used to construct similar scales in children. Subjects were adults and children 4, 6, 8, and 12 years old. Their task was, first, to match the loudness of a 1000-Hz tone to various visual lengths, and, second, to match the length of a white tape to various loudnesses of the tone. Almost all subjects were able to perform the matching tasks; the average precision of older subjects (12 and Adult) was somewhat greater, but in each of the younger age groups a majority of subjects performed with a precision that equaled that of older subjects. The exponent of the power function that relates length and loudness does not change with age. The scale factor does change, in a way that suggests either that a given sound intensity seems softer, or, more probable, that a given length seems longer, to younger children. The success of cross-modal matching with subjects as young as 4 years means that it is possible to investigate not only single perceptual scales but also intermodal organization in young children.     

The influence of the minority on perception: A note on a possible alternative explanation

This research note raises some concerns about possible alternative explanations to studies using perceptual change as indicative of minority vs majority influence. Having failed to replicate the original study (S. Moscovici & B. Personnaz, Journal of Experimental Social Psychology 1980, 16, 270–282), using the same and an alternate measuring procedure, inspection of additional data introduces the role of suspiciousness in explaining this and previous findings. An informal study adds further credence to this explanation.