The role of coding time in estimating and interpreting growth curve models

The coding of time in growth curve models has important implications for the interpretation of the resulting model that are sometimes not transparent. The authors develop a general framework that includes predictors of growth curve components to illustrate how parameter estimates and their standard errors are exactly determined as a function of receding time in growth curve models. Linear and quadratic growth model examples are provided, and the interpretation of estimates given a particular coding of time is illustrated. How and why the precision and statistical power of predictors of lower order growth curve components changes over time is illustrated and discussed. Recommendations include coding time to produce readily interpretable estimates and graphing lower order effects across time with appropriate confidence intervals to help illustrate and understand the growth process.     

Integrating rewards and cognition in the frontal cortex

Research indicates that the dorsolateral prefrontal cortex (DLPFC) contributes to working memory and executive control, whereas the ventral frontal cortex (VFC) contributes to affective and motivational processing. Few studies have examined both the functional specificity and the integration of these regions. We did so using fMRI and a verbal working memory task in which visual cues indicated whether recall performance on an upcoming trial would be linked to a monetary reward. On the basis of prior findings obtained in delayed response tasks performed by nonhuman primates, we hypothesized that (1) VFC would show an increase only in response to a cue indicating potential for a monetary reward; (2) DLPFC would show sustained activity across a delay interval for all trials, though activity in rewarded trials would be enhanced; and (3) regions engaged in speech-based rehearsal would be relatively insensitive to monetary incentive. Our hypotheses about DLPFC and rehearsal-related regions were confirmed. In VFC regions, we failed to observe statistically significant effects of reward when the cue or delay epochs of the task were examined in isolation. However, an unexpected and significant deactivation was observed in VFC during the delay epoch; furthermore, a post hoc voxelwise analysis indicated a complex interaction between (1) the cue and delay epochs of the task and (2) the reward value of the trials. The pattern of activation and deactivation across trial types suggests that VFC is sensitive to reward cues, and that portions of DLPFC and VFC may work in opposition during the delay epoch of a working memory task in order to facilitate task performance.     

Stereotypes as dominant responses: on the "social facilitation" of prejudice in anticipated public contexts

This article challenges the highly intuitive assumption that prejudice should be less likely in public compared with private settings. It proposes that stereotypes may be conceptualized as a type of dominant response (C. L. Hull, 1943; R. B. Zajonc, 1965) whose expression may be enhanced in public settings, especially among individuals high in social anxiety. Support was found for this framework in an impression formation paradigm (Experiment 1) and in a speeded task designed to measure stereotypic errors in perceptual identification (Experiment 2). Use of the process dissociation procedure (B. K. Payne, L. L. Jacoby, & A. J. Lambert, in press) demonstrated that these effects were due to decreases in cognitive control rather than increases in stereotype accessibility. The findings highlight a heretofore unknown and ironic consequence of anticipated public settings: Warning people that others may be privy to their responses may actually increase prejudice among the very people who are most worried about doing the wrong thing in public.     

Power moves: complementarity in dominant and submissive nonverbal behavior

Two studies examine complementarity (vs. mimicry) of dominant and submissive nonverbal behaviors. In the first study, participants interacted with a confederate who displayed either dominance (through postural expansion) or submission (through postural constriction). On average, participants exposed to a dominant confederate decreased their postural stance, whereas participants exposed to a submissive confederate increased their stance. Further, participants with complementing responses (dominance in response to submission and submission in response to dominance) liked their partner more and were more comfortable than those who mimicked. In the second study, complementarity and mimicry were manipulated, and complementarity resulted in more liking and comfort than mimicry. The findings speak to the likelihood of hierarchical differentiation.     

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Components of IQ Scores Across Levels of Measured Ability

Forty-three (43) students from the Talent Identification Program's Summer Residential Program living in North Carolina took the Wechsler Intelligence Scale for Children—Revised (WISC-R; Wechsler, 1974) during the program. The test was also administered to 50 other North Carolina Students who qualified for the SRP but did not attend, as well as 34 students who had not been identified as gifted. The scores were evaluated for normative and idiographic strengths and weaknesses on the 12 subtests of the WISC-R. The idiographic differences were calculated by comparison against the average score of only the 6 subtests in the same subscale of the test (Verbal or Performance) as well as against all 12 subtests on the test. It was found by means of the former comparisons that the gifted students showed significantly more idiographic strengths on the Verbal scales and weaknesses on the Performance scales than the academically competent sample.     

Improving lecture comprehension: Effects of a metacognitive strategy

In previous research self-questioning strategies have been found to significantly improve reading comprehension, presumably because of the metacognitive nature of the self-questioning process. The purpose of the present study was to determine whether this metacognitive strategy also enhances lecture comprehension, that is, comprehension of non-text, orally presented material. In a self-questioning combined with reciprocal peer-questioning condition, ninthgraders were trained to pose questions for themselves during classroom lectures; following the lectures, they used their questions to engage in reciprocal peer-questioning and responding. Students in a self-questioning only condition also engaged in self-questioning during the lectures and then answered their own questions; in a review condition, students discussed the lecture material in small cooperative groups; and in a control group students reviewed the lecture material independently. On post-practice and 10-day maintenance tests participants in the self-questioning with reciprocal peer-questioning and the self-questioning only strategy groups showed lecture comprehension superior to that of participants in both the discussion review and control groups. These results suggest that: use of a self-questioning strategy can improve high school students' comprehension of lectures; students can maintain this strategy when external prompts are removed; and this metacognitive strategy can be readily taught to high school students and incorporated into their real-world classroom learning environment.     

Ask me why,don't tell me why: Asking children for explanations facilitates relational thinking

Identifying abstract relations is essential for commonsense reasoning. Research suggests that even young children can infer relations such as “same” and “different,” but often fail to apply these concepts. Might the process of explaining facilitate the recognition and application of relational concepts? Based on prior work suggesting that explanation can be a powerful tool to promote abstract reasoning, we predicted that children would be more likely to discover and use an abstract relational rule when they were prompted to explain observations instantiating that rule, compared to when they received demonstration alone. Five- and 6-year-olds were given a modified Relational Match to Sample (RMTS) task, with repeated demonstrations of relational (same) matches by an adult. Half of the children were prompted to explain these matches; the other half reported the match they observed. Children who were prompted to explain showed immediate, stable success, while those only asked to report the outcome of the pedagogical demonstration did not. Findings provide evidence that explanation facilitates early abstraction over and above demonstration alone.     

Methods of data collection,perceptions of risks and losses,and motivation to give truthful answers to sensitive survey questions

Two experiments examined survey respondents' concerns about risks and losses when answering sensitive questions in a survey. In Experiment 1 subjects watched one of eight different versions of a videotaped staged interview of a woman being asked about abortion and drunk driving. Experiment 2 was an actual survey interview about women's health issues, including abortion. In Experiment 2, a large proportion of the sample had a recent abortion for which validation information from the clinic was available. Results of both experiments indicate that, when responding to questions about sensitive topics, survey respondents are concerned about risks and losses other than those covered by standard confidentiality assurances and that these other concerns affect truthful reporting. Experiment 1 showed the importance of privacy in surveys of sensitive behaviours. The experiments suggest that under some circumstances interviewer‐administration of sensitive questions may produce data as good as or better than self‐administration. Copyright © 1999 John Wiley & Sons, Ltd.