Teaching posttraining: influencing diagnostic strategy with instructions at test

It is believed that medical diagnosis involves two complementary processes, analytic and similarity-based. There is considerable debate as to which of these processes defines diagnostic expertise and how best to teach clinical diagnosis and reduce diagnostic errors. The purpose of these studies is to document the use of these strategies in medical students. We shifted the balance in use of these processes and improved diagnostic accuracy with instructions given posttraining at the moment of diagnosis. Analytic processing reflecting the degree to which cases contain the diagnostic rules was indexed by the rate of accuracy on typical versus atypical cases (typicality effect). Similarity-based processing reflecting the degree to which cases resemble previously encountered cases was indexed by the rate of accuracy on similar versus dissimilar cases (similarity effect). Two studies are presented illustrating that diagnosis involves the coordination of analytic and similarity-based processes and that differential instruction given at test shifts the balance in the use of these processes. Study 1 illustrated that participants adopting an analytic strategy exhibit a larger effect of typicality. Participants adopting a similarity-based strategy exhibit a larger effect of similarity. The diagnostic approach of students given no instructions was predominantly analytic. Dual instructions in which participants first employed similarity-based processing followed by the application of rules improved overall accuracy. Study 2 investigated two versions of dual instructions and illustrated that assessing a case with the rules of diagnosis first may inhibit the subsequent use of similarity-based reasoning. The implications for diagnostic expertise and pedagogy are discussed.     

Reversing the Signaled Magnitude Effect in Delayed Matching to Sample: Delay-specific Remembering

Pigeons performed a delayed matching‐to‐sample task in which large or small reinforcers for correct remembering were signaled during the retention interval. Accuracy was low when small reinforcers were signaled, and high when large reinforcers were signaled (the signaled magnitude effect). When the reinforcer‐size cue was switched from small to large partway through the retention interval, accuracy accordingly changed from low to high. The opposite happened when the cue was switched from large to small. This dissociation of forgetting from the passage of time raises the possibility that remembering is delay‐specific. The reversal of the signaled magnitude effect during the retention interval is consistent with an attentional account in which the stimulus control of remembering is influenced by extraneous events.     

Susceptibility to peer influence: using a performance-based measure to identify adolescent males at heightened risk for deviant peer socialization

A substantial amount of research has suggested that adolescents' attitudes and behaviors are influenced by peers; however, little is known regarding adolescents' individual variability, or susceptibility, to peer influence. In this study, a performance-based index from an experimental paradigm was used to directly measure adolescents' susceptibility to peers. A total of 36 adolescent boys participated in a "chat room" experiment in which they ostensibly were exposed to deviant or risky social norms communicated either by high-peer-status (i.e., popular, well-liked) or low-peer-status (i.e., unpopular, disliked) grade mates who actually were electronic confederates. Changes in adolescents' responses before and after exposure to peer norms were used as a measure of peer influence susceptibility. These same adolescents completed a questionnaire assessment at the study outset and again 18 months later to assess their actual engagement in deviant behavior and their perceptions of their best friend's engagement in deviant behavior. Only among adolescents with high levels of susceptibility to high-status peers was a significant longitudinal association revealed between their best friend's baseline deviant behavior and adolescents' own deviant behavior 18 months later. Findings support the predictive validity of a performance-based susceptibility measure and suggest that adolescents' peer influence susceptibility may generalize across peer contexts.     

Analysis of us-preexposure effects in appetitive conditioning

In two experiments, rats received preexposure to one type of food followed by autoshaping in which presentation of one lever was associated with the preexposed food, and presentation of another lever with a novel type of food pellet. In both it was found that acquisition of the leverpress response occurred more readily on the lever associated with the novel food. This example of the US (unconditioned stimulus) preexposure effect is not to be explained in terms of the development of competing responses during preexposure. Explanations in terms of blocking by contextual cues and of habituation to the US are considered.     

Optimal drug use and rational drug policy

The Müller & Schumann (M&S) view of drug use is courageous and compelling, with radical implications for drug policy and research. It implies that most nations prohibit most drugs that could promote happiness, social capital, and economic growth; that most individuals underuse rather than overuse drugs; and that behavioral scientists could use drugs more effectively in generating hypotheses and collaborating empathically.     

Hindsight bias from 3 to 95 years of age

Upon learning the outcome to a problem, people tend to believe that they knew it all along (hindsight bias). Here, we report the first study to trace the development of hindsight bias across the life span. One hundred ninety-four participants aged 3 to 95 years completed 3 tasks designed to measure visual and verbal hindsight bias. All age groups demonstrated hindsight bias on all 3 tasks; however, preschoolers and older adults exhibited more bias than older children and younger adults. Multinomial processing tree analyses of these data revealed that preschoolers' enhanced hindsight bias resulted from them substituting the correct answer for their original answer in their recall (a qualitative error). Conversely, older adults' enhanced hindsight bias resulted from them forgetting their original answer and recalling an answer closer to, but not equal to, the correct answer (a quantitative error). We discuss these findings in relation to mechanisms of memory, perspective taking, theory of mind, and executive function.     

Different confidence-accuracy relationships for feature-based and familiarity-based memories

Participants studied naturalistic pictures presented for varying brief durations and then received a recognition test on which they indicated whether each picture was old or new and rated their confidence. In 1 experiment they indicated whether each "old"/"new" response was based on memory for a specific feature in the picture or instead on the picture's general familiarity; in another experiment, we defined pictures that tended to elicit feature versus familiarity responses. Thus, feature/familiarity was a dependent variable in 1 experiment and an independent variable in the other. In both experiments feature-based responses were more accurate than those that were familiarity based, and confidence and accuracy increased with duration for both response types. However, when confidence was controlled for, mean accuracy was higher for familiarity-based than for feature-based responses. The theoretical implication is that confidence and accuracy arise from different underlying information. The applied implication is that confidence differences should not be taken as implying accuracy differences when the phenomenal basis of the memory reports differ.