Overconfidence effects in category learning: a comparison of connectionist and exemplar memory models

Exemplar and connectionist models were compared on their ability to predict overconfidence effects in category learning data. In the standard task, participants learned to classify hypothetical patients with particular symptom patterns into disease categories and reported confidence judgments in the form of probabilities. The connectionist model asserts that classifications and confidence are based on the strength of learned associations between symptoms and diseases. The exemplar retrieval model (ERM) proposes that people learn by storing examples and that their judgments are often based on the first example they happen to retrieve. Experiments 1 and 2 established that overconfidence increases when the classification step of the process is bypassed. Experiments 2 and 3 showed that a direct instruction to retrieve many exemplars reduces overconfidence. Only the ERM predicted the major qualitative phenomena exhibited in these experiments.     

“Transient structures”: The effects of practice and distractor grouping on within-dimension conjunction searches

It has been stated that whereas between-dimension (color × orientation) conjunctions can be searched in a “parallel” fashion, within-dimension (color × color) conjunctions are necessarily searched in a “serial self-terminating” fashion (Wolfe et al., 1990). We explored the effects of practice (within 1-h experimental session) and distractor grouping on within-dimension conjunction search tasks. In Experiments 1 and 3, the stimuli were rectangles formed by two adjacent squares; in Experiment 2, the stimuli were plus signs formed by two segments and an intersection. In Experiments 1 and 2, observers were assigned to one of two experimental conditions: In one, all the distractors shared a simple feature (the color blue); in the other, distractors did not share that simple feature. In the first condition, search became more efficient with practice and observers’ performance was characterized by a shallow reaction time (RT) × set size slope; in the second condition, observers’ performance did not improve as much with practice. We propose that the differential effects of practice between these two experimental conditions can be explained in terms of distractor grouping induced by the shared color of the distractors. Experiment 3 showed that, with practice, a shallow RT × set size slope characterized observers’ search for a color × color target among four different distractors that shared a common color. The present results contradict a main tenet of some current visual search models— namely, that within-dimension conjunctions cannot be searched in parallel, and question the validity of using RT × set size slope functions to distinguish between preattentive versus attentive search.     

Audience response as a heuristic cue in persuasion

Previous research on the persuasive impact of an overheard audience has yielded conflicting results. In this study, we attempted to understand such audience effects within the framework of the heuristic model of persuasion. Subjects listened to an audiotaped persuasive message that conveyed arguments of either high or low quality and that was responded to by either an enthusiastic or an unenthusiastic overheard audience. In addition, subject involvement (high vs. low) was varied. Consistent with predictions, the audience response cue influenced postmessage opinions only under low involvement; under high involvement, only argument quality affected persuasion. Analyses that took into account subjects' need for cognition supported the additional hypothesis that individuals lower in need for cognition would be more responsive to the audience manipulation under low involvement. Thought-listing data and regression analyses provided further support for the heuristic model.     

Factors influencing assignment of pronoun antecedents

In two experiments a group of adult subjects and a group of 10 – 13 year old subjects completed sentences of the format NP1 V NP2 because Pro… The fragment, John telephoned Bill because he…, elicited completions such as had good news, which locate the impetus for telephoning in NP1 (John). The fragment, John admired Bill because he…, elicited completions such as was a fine athlete, which locate the impetus for admiring in NP2 (Bill). The assignment of the subject pronoun of the second clause as coreferential with NP1 or NP2 shows that this choice depends on a factor, direction of causality, which may be assigned to verb roots. This factor was isolated from interacting semantic and syntactic features of sentences in which the verbs occurred. Manipulation of these features resulted in greater or lesser salience of the direction of causality factor. The potential of this technique for investigation of verb semantics and for interaction of semantic, pragmatic and syntactic features in the psychological study of comprehension is discussed.     

Investigating the importance of the least supported phoneme on visual word naming

The least supported phoneme refers to the phoneme position within a word with which the fewest phonological neighbors overlap. Recently, it has been argued that the number of neighbors coinciding with the least supported phoneme is a critical determinant of pronunciation latencies. The current research tested this claim by comparing naming latencies to words that differed in terms of the number of neighbors overlapping with their least supported phoneme. The results revealed that words where many neighbors overlapped were named more rapidly than those where few neighbors overlapped. These results are explained using the dual-route cascaded model of reading aloud.     

Expectations of sensations,discomfort and fear in dental treatment

A hundred dental patients and 40 dentists were asked to describe the sensations, discomfort and fear which they associated with a number of dental treatments. A number of patients were also asked to describe their experiences immediately after routine conservation procedures. It was concluded that although patients could accurately anticipate the pattern of sensations involved in treatment (even if they had not experienced some of the procedures), they expected more intense sensations and greater discomfort and apprehension than they were likely to experience. Dentists expressed more realistic ideas about the sensations produced by dental treatment. The discrepancy in patients' expectations appears to persist in spite of many discontinuing experiences, the fear of treatment being fostered by discomfort and the intensity of sensations expected, by lack of experience and, to a modest degree, by uncertainty about the sensations anticipated. Cognitive theories of fear do not appear to explain all these influences adequately. These observations support the need for information about sensations in treatment to help not so much with the experience of dentistry but rather with its anticipation.