The effect of practice on the operative form of a rule was investigated by giving subjects an easy, perfectly predictive classification rule, followed by training in applying that rule to a set of practice items. On a subsequent transfer test, the accuracy and speed of classifying new items was strongly affected by similarity to previously seen items, suggesting that the effect of practice was not simply to automatize the rule. The effect occurred with pictorial, easily integrated stimuli, but not with lists of verbally stated features. Subjects generally did not have insight into the role of previous items in their performance. This dependence on prior episodes may be frequent in ecologically common conditions and is of special interest when the categorization rule becomes uncertain, as when a rule has only heuristic value.When dealing with a newly learned rule, one is often aware of relying on previous episodes of applying the rule. The specific materials or problems to which the rule was originally applied seem to have some privilege, particularly when the rule initially seems quite abstract. Understanding a difficult rule, or at least understanding how to apply it, seems to occur in terms of previous concrete applications. This impression is corroborated by Ross in his interesting work on remindings in problem solving (Ross, 1984(Ross, , 1987(Ross, , 1989 Ross & Kennedy, 1990). He demonstrated that performance while learning a word processing program or learning to solve simple probability problems is influenced by specific analogies with previously encountered problems.But what happens to these prior episodes of problem solving when the rule is not difficult, or when one has had sufficient practice to make it no longer seem difficult? Introspectively, the prior examples seem to disappear from active processing, a suggestion reflected in a wide variety of theories in cognitive psychology. In this article we argue that under common conditions, prior episodes retain an important role in helping apply the rule to new material, well after clear awareness of the prior episodes has disappeared. We make an ecological argument for the conditions under which episode-based knowledge has continued value. Abstractive GeneralizationAn intuitively plausible view of the changes in processing that occur during practice with a rule is what we will refer to as abstractive generalization. With increasing practice, processing comes under the control of fast, general, and automatic procedures that concentrate solely on the relevant information given in the stimulus display. With practice, a rule that was explicitly known becomes automatized, consuming a decreasThis research was carried out with the support of the Natural Sciences and Engineering Research Council of Canada, through a graduate scholarship to Scott W. Allen and a grant to Lee R. Brooks.

To examine the development of expertise in dermatology, accuracy of diagnosis and response times of subjects at five levels of expertise were assessed. A total of 100 slides, 2 typical and 3 atypical slides from each of 20 common skin disorders, were presented to six subjects at each of the following levels: second-year preclinical medical students, final year medical students, residents in family medicine, general practitioners, and dermatologists. Accuracy of diagnosis rose from 21% for medical students to 87% for dermatologists. Correct diagnosis was associated with a decrease in response time with expertise, whereas errors were associated with a dramatic increase in response time, and was slower than correct response times at all levels, suggesting that errors do not result predominantly from carelessness or speed. Typical slides accounted for a constant proportion of diagnostic errors at all higher levels of expertise, and experts continued to make a significant proportion of errors on slides shown to be relatively easy for residents. The results are shown to be at variance with any model that equates expertise with the mastery of complex rules, but they are consistent with models of expertise that propose that expertise is equated with a rapid "pattern-recognition" process, and errors result from unintended confusion with previous similar examples.

Having read a word does more to benefit its later perceptual identification when many, rather than few, of the words in the test list have been previously read. Some have suggested that this proportion overlap effect is produced by an intentional use of recognition memory or recall in the perceptual identification task. Contrary to this account, we found that words that are easily recognized (words generated from an anagram at study) do not gain more from increasing overlap than do words that are poorly recognized (words read at study). These findings are problematic for claims that word perception relies on a module, such as a logogen system, that is separate from the rest of memory.Evidence of memory is often shown by performance on an indirect test, although a direct test reveals no evidence of memory (for reviews, see Johnson & Hasher, 1987;Richardson-Klavehn & Bjork, 1988). For example, reading a word makes it more likely that a person will be able to identify the word later when it is flashed for a test of perceptual identification, and that effect on perception is observed even when the person does not recognize the word as previously read (e.g., Jacoby & Dallas, 1981). The test of perceptual identification is an indirect test of memory because the instructions refer only to the task at hand and do not refer back to a particular prior event, although the subject's performance on the task might be influenced by memory for that prior event. Recognition and recall are direct tests of memory because the instructions refer to a target event in the personal history of the subject and ask the subject to consciously recollect that earlier event. We use the phrase unconscious influences ofmemory (e.g., Jacoby & Kelley, 1987) to refer to effects of a prior experience that arise on an indirect test of memory although a person is unable to recall or recognize the relevant prior experience. Others (e.g., Graf & Schacter, 1985) have referred to such effects as effects on implicit memory.A major problem for using indirect tests as a means of investigating unconscious influences of memory is that performance on these tests might sometimes reflect aware influences of memory that are undetected by the experimenter. Although not instructed to use memory for a particular prior event, subjects given an indirect test of memory might sometimes discover the relation between study and test and intentionally use memory much as they would for a direct test of memory. The problem is similar to the one that has plagued attempts to show unconscious perception. Indeed, because of the possibility of awareness undetected by the experimenter, Holender (1986) argues that there is no convincing evidence for the existence of unconscious perception. Similarly, in studies of memory, Richardson-Klavehn and Bjork (1988) note that many effects ascribed to unconscious influences of memory might be contaminated by conscious recollection. For example, the enhanced perceptual identification performance of old, relative to new, words might sometimes r...

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Queen's University at KingstonStudies investigating men and women separately suggest a sex difference in the habituation of genital responses to sexual stimuli: Men's responses habituate readily whereas women's responses appear more resistant. These studies also demonstrate that attention is positively correlated with habituation effects when they occur. The preparation hypothesis asserts that women's genital responses occur automatically in the presence of sexual cues to protect them from injuries that may occur as a result of penetration. It follows that women may not habituate as much as men because the costs of not responding to sexual cues are likely higher for women than they are for men. In a recent study we found similar and pronounced habituation effects for genital responses and self-reported attention in men and in women. The aims of the current study were to examine whether habituation can be elicited when attention is maintained and if a sex difference would be observed. Thirty-six men and women were presented with 14 audiovisual stimuli following a within-subjects habituation design. Genital responses were measured using circumferential phallometry and vaginal photoplethysmography. Poststimulus ratings of sexual arousal and attention were recorded. Results showed habituation of genital but not subjective sexual responses in both sexes. Participants reported a high degree of attention across habituation trials, but controlling for changes in attention eliminated habituation effects for genital responses. The role of attention in sexual responses and the implications of our findings for the preparation hypothesis are discussed.