Hippocampal synaptic plasticity during instrumental learning

present research examined the role of hippocampal NMDA-dependent synaptic potentiation on appetitive instrumental conditioning under a continuous reinforcement schedule. In the first experiment, low (.025 mg.kg) or moderate (.05 mg/kg) dosages of the NMDA receptor antagonist, MK801, failed to increase the number of training days required to reach acquisition criterion; number of training days required to reach criterion for extinction were also unaffected. In the second experiment, a higher dosage (.10 mg/kg) of MK801 or induction of long-term potentiation failed to alter the number of responses occurring during acquisition. These data suggest that hippocampal synaptic potentiation does not play a prominent role in instrumental learning with simple contingency conditions. It is suggested that hippocampal LTP reflects a perceptual process that contributes differentially to spatial cognition, classical and instrumental conditioning.     

Gender bias and individualism: Responses to case vignettes among psychologists, professors, and students

This study examined the extent to which psychologists, when compared to university professors and evening school students, employ individualist values differentially in their responses to vignettes describing males and females. The participants responded to 6 vignettes by choosing initial hypotheses that reflected either utilitarian (tradition-ally masculine) or expressive (traditionally feminine) themes. Two vignettes involved a sex of client manipulation, but neither resulted in a sex of client effect. An analysis of the responses to the remaining 4 vignettes indicated a marked preference for the masculine form of individualism for males, but were evenly divided for females in all three groups. These results suggest that psychologists were just as likely to engage in bias as others.     

TO WHAT EXTENT DO UNIQUE PARTS INFLUENCE RECOGNITION ACROSS CHANGES IN VIEWPOINT?

Abstract— We investigated how varying the number of unique pans within an object influences recognition across changes in viewpoint The stimuli were shaded objects composed of five three-dimensional volumes tinted end to end with varying connection angles Of the five volumes, zero, one, three, or jive were qualitatively distinct (e g, brick vs cone), the rest being tubes Sequential-matching and naming tasks depth Three major results stand out First, regardless of the number of distinct parts, there was increasingly poorer recognition performance viewpoint change for objects with one unique part was less than that for the other objects Third, additional pans beyond a single unique part produced strong viewpoint dependency comparable to that ob representations encode both quantitative and qualitative features     

THE CREDIBLE SHRINKING ROOM:

Abstract— Becoming a proficient symbol user is a universal developmental last in the first years of life, but delecting and mentally representing symbolic relations can be quite challenging for young children To test the extent to which symbolic reasoning per se is problematic, we compared the performance of 2-year-olds in symbolic and nonsymbolic versions of a search task. The children had to use their knowledge of the location of a toy hidden in a room to draw an inference about where to find a miniature toy in a scale model of the room (and vice versa) Children in the nonsymbolic condition believed a shrinking machine had caused the room to become the model They were much more successful than children in the symbolic condition, for whom the model served as a symbol of the room The symbol understanding and use.     

INTERRUPTING IRONIC PROCESSES

Abstract— Research on ironic mental control processes makes the under appreciated point that attempts to solve problems sometimes make them worse. Social scientists now know much about what ironic processes look like less about why they occur and too little about how to change them. Features of the exacerbation process itself suggest parsimonious approaches to treatment based on interrupting the "solutions" that keep ironic mental processes going (e.g. compliance-based paradoxical intervention). Extending Wegner's explication of ironic interpersonal (mental) processes we propose that ironic interpersonal (social) processes also maintain many human problems in this area will benefit from attending more to how problems persist between people as well as within them.     

TIME COURSE OF ACTIVATING BRAIN AREAS IN GENERATING VERBAL ASSOCIATIONS

Abstract— Generating a use far a visual word in comparison with reading the word aloud activates frontal attention areas first (170 MS), a left lateral frontal area next (250 ms), and then a left temporoparietal (Wernicke's) area (650 ms). A brief period of practice reduces these activations. If subjects are asked to respond to a word from the same practiced list by giving a novel use, the original activations reappear and are joined by activity similar in location and time to Wernicke's activation but in the right hemisphere. These findings demonstrate the time course of activations of neuroanatomical areas in word processing and indicate a role for the right hemisphere when semantic processing is more difficult, such as in generating a less frequent association in the presence of a highly practiced one.     

Changes in Newcomers' Person–Climate Fit following the First Stage of Socialization

The development of attitudes and activities of newcomers in the 18 months following the first period of socialization was investigated. At two points in time, persons' preferences for seven work climates were compared with perceived climate. Changes in person-climate fit were assessed, using a squared difference index, after alternative fit-indices were tested with hierarchical regression analysis. Person-climate fit and work attitudes at T1 (eight to ten months after entry) were examined by comparing three groups of respondents who did not change jobs, changed jobs within the organization or changed organizations. Results showed no alpha, beta or gamma changes for the total group of 108 respondents. Alpha changes were only found for respondents who changed jobs. They showed higher ratings for job satisfaction at T2. Finally, work attitudes at T1 were related to turnover. Organizational changers showed higher turnover intentions and higher discrepancies between preferred and perceived risk orientation and work pressure at T1.     

Confirmatory Factor Analysis of U.S. Merit Systems Protection Board's Survey of Sexual Harassment: The Fit of a Three-Factor Model

Research over the past decade and a half exploring the psychological dimensions of the definition of sexual harassment has converged on a three-factor model: gender harassment, unwanted sexual attention, and sexual coercion. The current study used confirmatory factor analysis to determine whether the most widely used sexual harassment survey, the U.S. Merit Systems Protection Board (USMSPB; 1981) survey, measures this three-factor structure. Data from a sample of the USMSPB's 1988 survey of Federal employees (n= 1070) and from a midwestern university's survey of undergraduates (n= 572) and graduate students, faculty, and staff (n= 575) were analyzed. The three-factor model fit reasonably well in all samples, but two survey items, measuring sexual assault and sexual favors, were weakly related to their respective factors. This model, however, was only marginally stable across female and male subsamples, and gender harassment and unwanted sexual attention had low discriminant validity. Both practical and theoretical implications are discussed.     

EMERGENCE OF REINFORCER PREFERENCE AS A FUNCTION OF SCHEDULE REQUIREMENTS AND STIMULUS SIMILARITY

Tustin (1994) recently observed that an individual's preference for one of two concurrently available reinforcers under low schedule requirements (concurrent fixed-ratio [FR] 1) switched to the other reinforcer when the schedule requirements were high (concurrent FR 10). We extended this line of research by examining preference for similar and dissimilar reinforcers (i.e., those affecting the same sensory modality and those affecting different sensory modalities). Two individuals with developmental disabilities were exposed to an arrangement in which pressing two different panels produced two different reinforcers according to progressively increasing, concurrent-ratio schedules. When two dissimilar stimuli were concurrently available (food and a leisure item), no clear preference for one item over the other was observed, regardless of the FR schedules in effect (FR 1, 2, 5, 10, and 20). By contrast, when two similar stimuli were concurrently available (two food items), a clear preference for one item emerged as the schedule requirements were increased from FR 1 to FR 5 or FR 10. These results are discussed in terms of implications for conducting preference assessments and for selecting reinforcers to be used under training conditions in which response requirements are relatively high or effortful.