In defence of a ratio model for movement detection at threshold

Sutherland (1961) proposed that the detection of motion might depend upon the ratios of firings in cells sensitive to movement in opposite directions. Sekuler and his collaborators have argued that the notion of a ratio mechanism at threshold is wrong. The findings and arguments upon which this conclusion was based are challenged, an explicit model is described which provides an account of data previously held to be inconsistent with a ratio model, and an experiment is reported which provides unequivocal support for the ratio model and whose findings are inconsistent with the predictions from Sekuler's “independence” model.     

Studies in social influence: V. Minority influence and conversion behavior in a perceptual task

The effects of influence attempts by a majority and by a minority were examined on both a manifest response level and a latent perceptual level. Female subjects were exposed to a series of blue slides that were consistently labeled as green by a female confederate. The confederate was presented as a member of either a majority or a minority. On each trial, subjects were required to indicate the color of the slide presented and the color of the afterimage perceived on a white screen following removal of the slide. It was predicted that (a) the subject's judgment of the chromatic afterimage would be modified when the influence agent represented a minority, and (b) this modification will be more pronounced when the source of influence is absent than when it is present. The results supported the prediction in both the main study and its replication.     

Some determinants of task preference and the desire for information about the self

This research examined the influence of task difficulty and diagnosticity (ability information) on task choice and preference. It was found that males preferred diagnostic over non-diagnostic tasks, but among females significant preferences along this variable were not exhibited. Furthermore, the desire to obtain ability-relevant information decreased as a function of prior knowledge about one's ability. Both high and low ability self-perceptions, induced through prior experiences of success and failure, decreased the attraction toward diagnostic in formation. There was no indication that individuals with high ability self-concepts are especially avoidant of further ability-relevant information, as recent literature has suggested. In addition, and contrary to prior findings, difficult tasks were most preferred rather than easy or intermediate tasks, given that diagnosticity is held constant.     

Field-dependence,extraversion, Eysenck and autarky

The research literature was examined with regard to relationships between Field-dependence and Extraversion. Eysenck's contention that the two variables are significantly related to an extent justifying the use of causal hypotheses based on extraversion theory to account for field-dependent behavior was not supported.     

Apple II/FIRST system control of electrical brain stimulation in the rabbit

An Apple II/FIRST system has been developed to control classical conditioning experiments, collect analog data, and extract dependent variable measures of conditioning from uniphasic (Scandrett & Gormezano, 1980) and multiphasic (Johnson, 1981) response signals. The present paper details the development of an electrical brain stimulation system as a peripheral device to the Apple II/FIRST system. In addition, data are presented that document the capabilities of the EBS system to concurrently stimulate up to eight animals while values along the dimension of each of four stimulation parameters are manipulated by a program written in FIRST. In our judgment, the EBS system has a number of advantages over currently available commercial stimulators, including cost, number of sites that can be independently stimulated, and availability of complete software control.     

FUNCTIONAL ASSESSMENT,CURRICULAR REVISION,AND SEVERE BEHAVIOR PROBLEMS

An adolescent female with multiple handicaps and a long history of severely disruptive behavior participated in a functional assessment linked directly to specific revisions in her school curriculum. During Phase 1, reversal designs were used to test hypotheses pertaining to antecedent and auricular influences on problem behavior. During Phase 2, a multiple baseline across afternoon and morning time periods demonstrated that the auricular revisions were effective in eliminating severely disruptive behavior and increasing on-task responding. Data also showed that inappropriate “psychotic” speech was reduced and appropriate social interactions were increased. Follow-up results showed that the changes were maintained throughout the school year. Questionnaire data provided social validation of the procedures and outcomes. The findings are discussed in relation to their implications for functional assessment, individualized curricula, and positive programming for students with disabilities and serious behavior problems.