Targets' Awareness of Expectations and Behavioral Confirmation in Ongoing Interactions

Participants engaged in a getting-acquainted interaction over an intercom after one participant (the perceiver) was provided with a positive (extraverted) or relatively negative (introverted) expectation about the other participant (the target). After completing evaluations of each other and the interaction, participants interacted for a second time. Prior to this second interaction, however, targets were made aware of the perceivers' initial expectation, told that it had been confirmed by their own behavior, and given a randomly assigned attribution (either dispositional or situational) about the perceived cause of their confirmatory behavior. Results demonstrated that targets made aware of dispositionally attributed and relatively negative expectations were more likely to increase in expectation-disconfirming behavior, compared to targets made aware of situationally attributed and relatively negative expectations, who were themselves more likely to continue to confirm the expectations. Implications for the study of behavioral confirmation of expectations and other interpersonal processes are discussed.     

Effects of caffeine on performance of low intensity tasks

31 college age men and women who consume less than three caffeinated beverages per week agreed to participate as subjects in research on the effects of acute caffeine intake on low intensity task performance. All subjects performed two randomly administered test conditions: (1) caffeine (5 mg/kg) and (2) placebo on separate visits following an initial 1-hr. orientation visit. Subjects were administered the beverage 30 min. prior to performing 12 separate tests assessing basic mathematics, simple response, logical reasoning, hand-eye coordination, and spatial and assembly skills. The Spielberger State Anxiety test was administered immediately after consuming the test beverage and once again at posttest. Analysis showed that caffeine did not significantly affect performance on all tests with the exception of the peripheral awareness (hand-eye coordination) test on which performance was higher after ingesting caffeine. The placebo treatment produced no effect on state anxiety, which contrasted with a significant rise in anxiety after caffeine consumption. State anxiety values were significantly greater after caffeine treatment relative to the placebo at pretest, and this difference persisted at posttest. These results demonstrated that the dose of caffeine increased scores on state anxiety for individuals who consumed less than three caffeinated beverages weekly but had very little effect on performance of low intensity tasks, except for a hand-eye coordination test involving peripheral awareness. Perhaps longer continuous performance of more demanding tasks would be more sensitive.     

MMPI-A validity scale uses and limitations in detecting varying levels of random responding

Although there is a substantial research literature on the effects of random responding on the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989), there are very few studies available on this topic with the MMPI-A (Butcher et al., 1992). Archer and Elkins (1999) found that MMPI-A validity scales F and VRIN were particularly useful in detecting entirely random profiles from those derived standardly in clinical settings but noted that "all random" protocols could not be used to evaluate the usefulness of the T-score difference between the first half (F1) and the second half (F2) of the MMPI-A test booklet. Following up on this issue, this study extended the methodology of previous research by examining the hit rate, positive predictive power, negative predictive power, sensitivity, and specificity of VRIN, F, F1, F2 and the absolute value of the T-score difference between F1 and F2 (denoted as IF1-F21) in 5 samples varying in the degree of protocol randomness. One of the samples consisted of 100 adolescent inpatients administered the MMPI-A under standard instructions, and another sample consisted of 100 protocols randomly generated by computer. The additional 3 samples of 100 protocols each contained varying degrees of computer-generated randomness introduced in the latter half of the MMPI-A item pool. Over- all, the results generally indicate that several MMPI-A validity scales are useful in detecting protocols that are largely random, but all of these validity scales are more limited in detecting partially random responding that involves less than half the total item pool located in the second half of the test booklet. Clinicians should be particularly cautious concerning validity inferences based on the observed T-score difference that occurs for the F1 and F2 subscales and current findings do not support the clinical usefulness of this index.     

Effects of pyridoxine on dreaming: a preliminary study

The effect of pyridoxine (Vitamin B-6) on dreaming was investigated in a placebo, double-blind study to examine various claims that Vitamin B-6 increases dream vividness or the ability to recall dreams. 12 college students participated in all three treatment conditions, each of which involved ingesting either 100 mg B-6, 250 mg B-6, or a placebo prior to bedtime for a period of five consecutive days. The treatment conditions were completely counterbalanced and a two-day wash-out period occurred between the three five-day treatment blocks. Morning self-reports indicated a significant difference in dream-salience scores (this is a composite score containing measures on vividness, bizarreness, emotionality, and color) between the 250-mg condition and placebo over the first three days of each treatment. The data for dream salience suggests that Vitamin B-6 may act by increasing cortical arousal during periods of rapid eve movement (REM) sleep. An hypothesis is presented involving the role of B-6 in the conversion of tryptophan to serotonin. However, this first study needs to be replicated using the same procedures and also demonstrated in a sleep laboratory before the results can be considered certain.     

Age dissociates recency and lag recency effects in free recall

The temporal relations among word-list items exert a powerful influence on episodic memory retrieval. Two experiments were conducted with younger and older adults in which the age-related recall deficit was examined by using a decomposition method to the serial position curve, partitioning performance into (a) the probability of first recall, illustrating the recency effect, and (b) the conditional response probability, illustrating the lag recency effect (M. W. Howard & M. J. Kahana, 1999). Although the older adults initiated recall in the same manner in both immediate and delayed free recall, temporal proximity of study items (contiguity) exerted a much weaker influence on recall transitions in older adults. This finding suggests that an associative deficit may be an important contributor to older adults' well-known impairment in free recall.