Cholecystokinin elicits the complete behavioral sequence of satiety in rats.

The behavior of intact rats and rats with chronic gastric fistulas was observed and scored during a 60-min test period when they were offered liquid diet after 17 hr of food deprivation. Intact rats and rats with closed fistulas displayed a specific behavioral sequence at the end of each meal: They stopped eating, engaged in grooming and exploration for a short time, and then rested or slept. Thus, a fixed behavioral sequence characterizes satiety in the rat. Although the behavioral sequence of satiety was fixed, the cessation of feeding was not a sufficient condition for the appearance of the rest of the sequence: Quinine adulteration of the liquid diet stopped sham feeding but did not elicit the complete sequence. Intraperitoneal injection of the intestinal hormone cholecystokinin during sham feeding, however, elicited the complete sequence of satiety. The observation that cholecystokinin not only stops feeding but elicits the complete sequence of satiety supports our hypothesis that endogenous cholecystokinin is a satiety signal for the rat.     

Effects of modified instructions on the Washington University Sentence Completion Test of Ego Development

This research project was designed to investigate the possibility that asking subjects to respond in a mature manner when they take the Washington University Sentence Completion Test of Ego Development (WUSCTED) would result in higher test scores and improve the test-retest reliability of the measure. The results showed that there was a significant increase in Total Protocol Ratings (TPRs) and item sums in the experimental group (n = 32) over the control group (n = 32). In addition, the experimental group spent more time and used significantly more words in its response than did the control group. The question of improved test-retest reliability remains only tentatively resolved. The item sum scores showed a significantly higher correlation for the experimental instruction than for the control, although the test-retest agreement between TPR levels was insignificantly different in the two instructional groups.     

Language and hand: The dimension of referential competence1

Kinesic and verbal performance data were collected for two groups of women college seniors chosen to represent extremes in a type of verbal ability termed here referential competence. This ability is conceptualized in terms of degree of integration of symbolic and ikonic representation systems, i.e., the strength of the symbol-referent links in semantic memory. A criterion measure of referential competence was developed using deviation of color naming from word-reading times on the Stroop Color-Word test. Referential competence was shown to be statistically as well as conceptually unrelated to both the standard verbal intelligence and fluency measures, and to cognitive style. During a five-minute videotaped monologue about a personal experience, persons high in referential competence produced verbal material which was specific, vivid, and objective; in contrast to the subjective and general material of the low referential group; and also produced approximately three times as many object-focused hand movements, linked to rhythm and intonation patterns of speech but largely without decipherable content. The results suggest that motor schema have a continuing intrinsic role in mature speech production, related to structure rather than content of language.     

Using what we know: Consequences of intentionally retrieving gist versus item-specific information

The effect of a prior gist-based versus item-specific retrieval orientation on recognition of objects and words was examined. Prior item-specific retrieval increased item-specific recognition of episodically related but not previously tested objects relative to both conceptual- and perceptual-gist retrieval. An item-specific retrieval advantage also was found when the stimuli were words (synonyms) rather than objects but not when participants overtly named objects during gist-based recognition testing, which suggests that they did not always label objects under general gist-retrieval instructions. Unlike verbal overshadowing, labeling objects during recognition attenuated (but did not eliminate) test- and interference-related forgetting. A full understanding of how retrieval affects subsequent memory, even for events or facts that are not themselves retrieved, must take into account the specificity with which that retrieval occurs.     

Strategy variability: How too much of a good thing can hurt performance

Recent research (e.g., Siegler, 1996) has discovered the important and vital role that variability plays among strategy use and development over time. However, as many researchers have pointed out (e.g., Miller, 1993), the majority of the research addressing this issue has focused on the outcomes, rather than on the potentially more informative aspects of variability, strategy development, and the process of adaptation. In this study, we examined the role of variability during strategy development, utilizing a longitudinal method. Thirteen participants were studied over 3 months as they coached a simulated football team. The results suggest that variability plays a major role in adaptive skill acquisition in a dynamic environment--in the direction, however, opposite to that predicted by previous research done with simple static tasks.     

Depression,Confidence, and Decision: Evidence Against Depressive Realism

This research examined how retrospective self-assessments of performance are affected by major depression. To test the validity of the depressive realism versus the selective processing hypotheses, aggregate posttest performance estimates (PTPEs) were obtained from clinically depressed patients and an age-matched comparison group across 4 decision tasks (object recognition, general knowledge, social judgment, and line-length judgment). As expected on the basis of previous findings, both groups were underconfident in their PTPEs, consistently underestimating the percentage of questions they had answered correctly. Contrary to depressive realism, and in partial support of the selective processing account, this underconfidence effect was not reduced but modestly exacerbated in the depressed patients. Further, whereas the PTPEs of the comparison group exceeded that expected on the basis of chance alone those of the depressed individuals did not. The results provide no support for the depressive realism account and suggest that negative biases contribute to metacognitive information processing in major depression.The results reported in this paper are based on an extension of the MSc dissertation of Tiffany Fu, conducted in partial fulfillment of the degree of MSc in Research Methods in Psychology, University of Reading, 2003     

Temporally nonadjacent nonlinguistic sounds affect speech categorization

Speech perception is an ecologically important example of the highly context-dependent nature of perception; adjacent speech, and even nonspeech, sounds influence how listeners categorize speech. Some theories emphasize linguistic or articulation-based processes in speech-elicited context effects and peripheral (cochlear) auditory perceptual interactions in non-speech-elicited context effects. The present studies challenge this division. Results of three experiments indicate that acoustic histories composed of sine-wave tones drawn from spectral distributions with different mean frequencies robustly affect speech categorization. These context effects were observed even when the acoustic context temporally adjacent to the speech stimulus was held constant and when more than a second of silence or multiple intervening sounds separated the nonlinguistic acoustic context and speech targets. These experiments indicate that speech categorization is sensitive to statistical distributions of spectral information, even if the distributions are composed of nonlinguistic elements. Acoustic context need be neither linguistic nor local to influence speech perception.