Classical geometric illusion effects with nonclassical stimuli: Angular induction from decomposing lines into point arrays

Angular induction is the process by which one line segment can bias judgment of orientation and/or collinearity of another segment, and it has been established that the magnitude of error is a determinate function of the relative angle between the two. We examined how these known relationships are affected by decomposing the induction segment into an array of scattered points. The bias that was produced by such arrays was found to be consistent with a formal model of angular induction, with the strength of the effect decreasing as the scatter among the points was increased. This decline in strength was almost linear with a logarithmic transform of the dimensions of the stimulus array. We also evaluated the hypothesis that the induction stimulus is detected by one or more channels—for example, neurons—for which the sensitivity profiles are modeled as Gabor wavelets. The change in induction strength with increasing point scatter was not predicted by a single width of channel. However, the combined activity of an ensemble of channels that differed in width did match the perceptual effects if one also stipulated that each channel would respond maximally to a fine-line stimulus.     

School psychology-observation and reminiscence

Analyses of certain characteristics of the membership of the Division of School Psychology and some of its efforts are presented. Evidence is presented which suggests unequivocally that school psychologists, whom the schools clearly need, must be soundly grounded in relevant psychological testing theory, must be fully sensitive to the social characteristics and needs of each child in whose interests they work, and must be fully conversant with the relevance of their psychological perceptions to the educational functioning of those children.     

Effects of Eltoprazine Hydrochloride on Predatory Behavior in Rats

Treatment of rats with the potent antiaggressive compound eltoprazine hydrochloride (1.0 & 2.0 mg/kg) slowed both predatory attack and killing of frogs. These results demonstrate a specific predation-inhibiting action of the drug which is not obscured by the elements of conspecific aggression seen during muricide. Unlike the closely related compound fluprazine, eltoprazine increased both attack and kill latencies implying that the effects of the two drugs on predation are mediated by at least somewhat distinct drug actions. It is further suggested that eltoprazine may be more specifically antiaggressive in its actions than related phenylpiperazine compounds.

     

Effects of prior agonistic experience on risk assessment and approach behavior evoked by familiar or unfamiliar conspecific odors

Risk assessment and appetitive behaviors in response to familiar and unfamiliar conspecific odors were measured in mice rendered dominant or subordinate by a series of resident-intruder encounters. Subordinate mice showed elevated levels of risk assessment in response to the odors of both familiar dominant and unfamiliar males. These behaviors were almost totally absent among dominant males exposed to familiar subordinate or unfamiliar male odors. Subordinate mice showed a marginally significant elevation in latencies to approach familiar, but not unfamiliar, dominant odors. Dominant and subordinate mice spent comparable amounts of time in the cage area containing familiar antagonist odors, however, and the durations of subordinates were mildly elevated, rather than decreased, when unfamiliar conspecific odors were present. There were no group differences in any of the appetitive behaviors. These findings suggest that apparent preferences for conspecific odors may arise from quantitatively and/or qualitatively differing emotional states. The inclusion of risk assessment measures is suggested to be a useful adjunct for studies of olfactory preference/rejection. © 1994 Wiley-Liss, Inc.     

Birth month and suicide among major league baseball players

We examined the association between month of birth and completed suicides among major league baseball players (N = 76). More than twice as many players born in August committed suicide (N = 19) than any other birth month. This association was statistically significant when birth month was corrected for differences in days of the month. The differences were even larger when expressed in terms of birth month for those committing suicides divided by number of major league players born in each month. The association between birth month and suicide raises the possibility that prenatal factors may influence the inclination for suicide later in life.     

Educational attainment and suicide rates in the United States

We examined the relationship between educational attainment and suicide rate in the United States for 2001. Suicide rates, adjusted for age, were compared with percentage of college graduates, median household income, and poverty in 50 states in 2001. The correlations of suicide rates with educational attainment and median household income were both negative and statistically significant. Poverty was not significantly related to suicide rates. We concluded that higher education and income were associated with a decrease in suicide rates in 2001. Data from other years require examination for this conclusion to be generalizable.     

Assessing aggression in adolescent romantic relationships: can we do it better?

Almost all research on aggression in adolescent romantic relationships makes use of 1-time, retrospective assessment methods. In the present research, the authors compared data on the experience of adolescent relationship aggression (physical aggression and threatening behavior) collected from 125 high school students via 2 methods: (a) a 1-time, 2-month retrospective assessment and (b) a cumulative method based on four 2-week retrospective assessments, each spaced 2 weeks apart. For the cumulative method, data from the 4 assessments were aggregated to cover the same time period as the single, 2-month retrospective assessment. A greater proportion of the sample (48.0%) reported experiencing physical aggression using the cumulative method compared with the single, 2-month retrospective method (27.0%). The prevalence of threatening behavior was also higher using the cumulative method (48.8% vs. 24.8%). Adolescent trauma and anxiety symptoms correlated more strongly with physical aggression data derived from the cumulative method than from the 1-time assessment method.