Reaction time and diazepam plasma concentration in subjects with normal gastric pH

The present study investigated the relationship of reaction time with the plasma concentration of four different formulations of diazepam (liquid, original, new, and generic). On four separate days, over a 4-month period, subjects with normal gastric pH (N=7) were administered each of the diazepam formulations. Blood samples were obtained prior to each dose and at subsequent intervals. Likewise, reaction times were evaluated prior to dosing and then at ten different intervals post-dosing. As hypothesized, reaction time performance was associated with plasma diazepam concentration, regardless of formulation type. This suggests that reaction time is a sensitive measure of cerebral functioning for individuals who are treated with diazepam. In addition to providing a measure of drug effects on cognitive functioning, the results of this study have implications concerning possible hazards of operating machinery or driving motor vehicles for individuals being treated with diazepam.     

Internalizing problems of adolescents: The role of the informant in identifying family and individual difficulties

The purpose of this study was to examine the family environment and school functioning of adolescents who differed on level of internalizing problems as reported by the adolescent and her/his mother. Thirty-six adolescents, their mothers, and their social studies teacher served as participants. Three groups were formed based on the report of level of internalizing problems: high mother and adolescent report (high concordant); low mother/high adolescent report (discordant); and low mother/low adolescent report (low concordant). The results indicated that the high concordant group, but not the discordant group, differed significantly from the low discordant group in that adolescents from the former group were from home environments with more difficulties (more interparental conflict, maternal depression, & maternal anxiety) and had more internalizing problems and lower grades in school. The results point to the importance of parent-report data when clinically assessing adolescents or conducting research on internalizing problems of adolescents.     

Illusory Control as a Function of Motivation for a Specific Outcome in a Chance-Based Situation

Previous research has provided evidence that an individual's need for a chance-based outcome positively affects perceptions of the skill involved in attaining the outcome as well as certainty of winning. Two experiments were conducted to test several competing alternative interpretations for this effect. In Experiment 1, food-satiated (low-need) and food-deprived (high-need) subjects were given the opportunity to win a food incentive in a chance-based card-drawing game either in the presence or absence of situational cues previously shown to induce skill orientations. Skill and confidence-in-winning ratings were found to be positive function of outcome need regardless of the cues condition, thus not supporting an attentional or vigilance interpretation of the general effect. In Experiment 2, food-satiated and food-deprived subjects faced a similar card-drawing game, but this time were given the opportunity to choose whether or not they wanted to be personally involved in various facets of the game (e.g., shuffling the cards). As predicted, high-need subjects showed a greater propensity to want to be personally involved in playing the game, a finding offering support for a control interpretation. Overall results are discussed in terms of control theory.     

Individual and sex differences in reminiscence

Inverted alphabet printing, rotary pursuit, and mirror tracking tasks were administered to 84 subjects in order to ascertain (a) reproducibility of reminiscence scores within and between tasks and (b)sex differences in reminiscence. With prerest performance levels held constant by second-order partial correlation procedures, reproducibility of individual reminiscence differences within tasks was significant but quite low, while predictability of reminiscence from one task to another was negligible. The sexes reminisced essentially alike on inverted alphabet printing, but females reminisced more than males on the other tasks, presumably because they were relatively more depressed by massed practice on these tasks. Thus, individual and sex differences were essentially task specific. Implications of results for reminiscence theories and for the credibility of alleged relationships between reminiscence and other organismic variables were discussed.     

The recovery of a visually masked target

Ss were briefly shown pairs of letters under backward masking and disinhibitive backward masking conditions. For the backward masking condition, a single homogeneous flash of light (M1), varying in duration, followed the presentation of letters after a varying delay (IS11), and recognition of the target letters (TS) was found to be a function of M1 duration and ISI1. For the disinhibition condition, a variable second mask (M2) followed M1 after a variable delay (ISI2) and disinhibition of M1’s effect on TS recognition occurred. Provided the ISIs were adequate, a relatively powerful M2 wass found to disinhibit a moderate Ml’s effect on the TS. Current theories of visual masking were examined in the light of these findings.     

The effects of stimulus numerosity,retinal location,and rod contrast on perceived duration of brief visual stimuli

The effects of manipulating three stimulus parameters were determined on a standard perceived duration task using 40- and 70-msec visual stimuli. In Experiment 1, it was found that perceived duration increased with increasing number of target dots but decreased as the area that contained the dots also increased. Experiment 2 examined the effect of varying the retinal location (0, 2, or 4 deg from fovea) of the target dot and found perceived target duration to increase with increasing eccentricity. In Experiment 3, the background luminance for a constant red target was varied so as to alter the scotopic contrast of the target. Perceived duration was minimal for the scotopically matched target and background conditions. The results of all three experiments were discussed in terms of important retinal—and even rod—contributions to tasks of perceived duration.     

Division of attention between simultaneous and successive nonverbal signals varying in discriminability

Impaired performance indexed by accuracy usually accompanies the division of attention between simultaneous difficult signals. Presenting the signals successively reduces the impairment. Presenting easy signals eliminates it. Both variables crucial to these findings, relative time of onset and discriminability, were manipulated in the first experiment using a two-choice recognition paradigm involving bimodal signals. The results showed that, when a difficult signal was followed by two simultaneous easy ones, in a different modality from the first, performance was significantly worse on each than on the same signals presented alone. Simultaneous presentation of all three signals further increased the impairment for the difficult signal, but not for the easy ones. In the second experiment, the discriminability of the following signals was varied. The results showed, that when a difficult signal was followed by either two simultaneous easy signals, in a different modality from the first, or by two difficult ones, performance was significantly worse than on the same difficult signal presented alone. Further, when the preceding difficult signal was auditory, but not when it was visual, performance was better with easy following signals than with difficult ones. It is argued that an adequate account of the results from the two experiments requires the following assumptions concerning the processing of multiple signals: (1) a loss associated both with the acquisition and the storage of information, (2) preferential processing of visual signals over auditory ones. Proposals are made for the incorporation of both assumptions into a single model of divided attention.     

Contextual assimilation and its effect on the division of attention between nonverbal signals

Subjects performed a recognition task in which a low or a high frequency signal was presented simultaneously with a dim or a bright intensity one. The independent variable was the degree of association between the signals on the two dimensions. Unknown to the subjects four levels were tested in separate conditions, 1.0, 0.8, 0.5 and 0.2. Increasing the positive association improved overall sensitivity as measured by d' on both dimensions, but left contingent sensitivity unchanged. Changing the association did not affect overall bias, as measured by Beta. However, holding context constant by analysis produced significant differences between individual measures of contingent bias in the direction of assimilation, for example “low” responses tended to accompany dim signals and “dim” responses. The differences were unaffected by the changes in association. The results are interpreted as favouring models of contextual assimilation which assume that biasing at some level of processing depends upon the mutually contingent interaction of discrete events rather than on memory and expectation of the relative frequency of conjoint events. Further support for this conclusion comes from previous studies which indicate that assimilation occurs with separate responses but not with unitary ones. The implications of the findings for research on the division of attention are discussed, particularly the need to control variability in measured bias to establish a true change in the allocation of attention. Two generalized models of contextual assimilation are proposed, one based on “object” and the other on “lexical” assimilation. The possible application of these models to synaesthesia is considered.