The Effects of Intermittent Illumination on a Visual Inspection Task

Two experiments are described in which eye movements were monitored as subjects performed a simple target-spotting task under conditions of intermittent illumination produced by varying the display-screen frame rate on a computer VDU. In Experiment 1, subjects executed a saccade from a fixation point to a target which appeared randomly at a fixed eccentricity of 14 character positions to the left or right. Saccade latency did not differ reliably as a function of screen refresh rate, but average saccade extent at 70 Hz and 110 Hz was reliably shorter than at 90 Hz and 100 Hz. Experiment 2 examined the same task using a range of target eccentricities (7, 14, and 28 character positions to the left and right) and across a wider range of screen refresh rates. The results confirmed the curvilinear relationship obtained in Experiment 1, with average saccade extent reliably shorter at refresh rates of 50 Hz and 125 Hz than at 75 Hz and 100 Hz. While the effect was greater for remote targets, analyses of the proportional target error failed to show a reliable interaction between target eccentricity and display refresh rate. In contrast to Experiment 1, there was a pronounced effect of refresh rate on saccade latency (corrected for time to write the screen frame), with shorter latencies at higher refresh rates. It may be concluded that pulsation at frequencies above fusion disrupts saccade control. However, the curvilinear functional relationship between screen refresh rate and saccade extent obtained in these studies differs from previously reported effects of intermittent illumination on the average size of 'entry saccades' (the first saccade to enter a given word) in a task involving word identification (Kennedy & Murray, 1993a, 1996). This conflict of data may arise in part because withinword adjustments in viewing position, which are typical of normal reading, influence measures of average saccade extent.     

The relationship between infanticide and pregnancy block in mice

Newly pregnant mice are more likely to exhibit pregnancy block when females are exposed to infanticidal males rather than to noninfanticidal males. These data suggest that females are able to assess the risk to their future infants and adjust their reproductive tactic. Those females that did not exhibit pregnancy block in the presence of infanticidal males suffered a greater loss of pups than those in the presence of noninfanticidal males, demonstrating the advantage of pregnancy block. Females served by infanticidal or noninfanticidal males showed no difference in pregnancy block, but if the litter was produced, there was a greater loss of pups sired by infanticidal males.     

Adolescents' views of intimacy: distinguishing intimate from nonintimate relationships

Two hundred seventy-seven late adolescents were questioned regarding what they believed differentiated an intimate from a nonintimate relationship. Adolescents' responses supported Erickson's (1963) view of intimacy as being characterized by openness, sharing, and trust, with only minimal differences occurring between the sexes, and relative to current dating/relationship status. Their expressed views varied from Erickson's, however, as they included physical/sexual interaction as a critical component. An additional difference was the relatively few students who included self-abandonment and commitment as necessary elements of an intimate relationship. Explanations for these differences are presented.     

Development of an automated performance test system for environmental and behavioral toxicology studies

In developing a menu of computerized performance tests for repeated-measures applications the metric properties of selected tests have been examined. Factors of chief concern have been stability and reliability, as well as the practical issue of the length of time it takes to achieve high levels of both. In this study, these factors, as well as predictive validity, are examined. 25 subjects were tested repeatedly (10 sessions) with 11 tests previously identified as "good" candidates for repeated-measures research in paper-and-pencil (marker test) versions. The 11 tests were administered concurrently in their traditional paper-and-pencil modes and newly implemented microcomputer-based versions, along with the Wechsler Adult Intelligence Scale (WAIS). Nine of the 11 microcomputer-based tests achieved stability. Reliabilities were generally high, with r greater than or equal to .77 for 3 min. of testing. Cross-correlations of microbased tests with traditional paper-and-pencil versions suggest equivalency between the test constructs in the different media. Correlations between six of the microbased subtests and the WAIS identified common variance, and these might comprise an efficient short (6 min.) battery of tests.     

Automated Portable Test (APT) System: Overview and prospects

The Automated Portable Test (APT) System is a notebook-sized, computer-based, human-performance and subjective-status assessment system. It is now being used in a wide range of environmental studies (e.g., simulator aftereffects, flight tests, drug effects, and hypoxia). Three questionnaires and 15 performance tests have been implemented, and the adaptation of 30 more tests is underway or is planned. The APT System is easily transportable, is inexpensive, and has the breadth of expansion options required for field and laboratory applications. The APT System is a powerful and expandable tool for human assessment in remote and unusual environments.     

Dating infidelity: behaviors, reasons and consequences

Older adolescents were surveyed concerning three issues: behaviors which constitute infidelity in a dating relationship, reasons for a dating partner to be unfaithful, and reactions to a dating partner's infidelity. Responses from 247 participants indicated more similarities than differences between dating infidelity and extramarital affairs with regard to behaviors, causes, and consequences. Results are discussed in terms of similarities between dating and marital infidelity, and the rationale for professionals to interact with adolescents concerning the potential long-term consequences of dating infidelity.     

Perceptions of conventional war: late adolescents' views

Late adolescents' views concerning conventional war were assessed in order to better understand the thinking of today's youth and to compare their views with those of early adolescents previously reported in the literature. Three hundred ninety-nine college undergraduates from two universities were surveyed regarding conventional warfare in general and United States military involvement in Latin America specifically. Results suggest that attitudes toward war were related to sex, socioeconomic status, and political affiliation. Although two-thirds of the respondents believed wars were sometimes needed, there was little support for United States military involvement in Latin America and much skepticism of President Reagan's honesty on the issue. Overall, late adolescents' views were less positive and less extreme than were those of early adolescents.     

Therapist gender and the same-sex puberty age psychotherapy group

Puberty is considered to be the most difficult developmental period to conduct psychotherapy. Group psychotherapy has special appeal for pubescents because of the anxiety experienced in individual psychotherapy with adults, and the mutual identification and support experienced with groups of same-sex peers. Although pubescents readily form cohesive groups, the emotional stress for the group therapists is intense and many therapists are reluctant to take on such groups. Close attention to the principles of developmental ego psychology suggests that pubescent groups will be more effective if conducted by group therapists of the same sex as the patients.