IMPULSIVITY AND INHIBITORY CONTROL

Abstract— We report an experiment testing the hypothesis that impulsive behavior reflects a deficit in the ability to inhibit prepotent responses Specifically, we examined whether impulsive people respond more slowly to signals to inhibit (stop signals) than non-impulsive people In this experiment, 136 undergraduate students completed an impulsivity questionnaire and then participated in a stop-signal experiment, in which they performed a choice reaction time (go) task and were asked to inhibit their responses to the go task when they heard a stop signal The delay between the go signal and the stop signal was determined by a tracking procedure designed to allow subjects to inhibit on 50% of the stop-signal trials. Reaction time to the go signal did not vary with impulsivity, but estimated stop-signal reaction time was longer in more impulsive subjects, consistent with the hypothesis and consistent with results from populations with pathological problems with impulse control.     

A re-conceptualization of Erikson's identity stage

This brief theoretical paper argues that Erikson's concept of identity was originally proposed as something constructed to a significant degree by the individual, i.e., an Instrumental Identity. With the decline in instrumentality in a consumer/service-oriented society, Erikson's original concept fits less well. A new conceptualization of identity, that of Existential Identity, is proposed. Thus, the earlier issue of success versus failure at achieving an Instrumental Identity has begun to give way to a new dimension--of being either a victim or a beneficiary in seeking an Existential Identity. Alternatively, the stage of "adolescence" can be viewed as a stage of seeking Instrumental Identity, and Keniston's new stage of "youth" as the locus of the new Existential Identity.     

On alcoholism

Pastoral Psychology -     

A further investigation of apparent size and retinal size as determinants of the figural after-effect

A figure which is more distant from the eye than another but subtends the same visual angle is usually seen as the larger. This phenomenon is called perceptual size constancy. Experiments have been reported which show that sometimes the apparent and sometimes the retinal sizes of the stimulus figures determine the direction of the figural after-effect. These experiments are reviewed and two further experiments are reported. In the first experiment two types of stimulus figure (discs and annuli) which subtended a visual angle of 1° 36' resulted in figural after-effects, the direction of which would have been predicted by the retinal sizes of the figures. In the second experiment larger figures were used which subtended a visual angle of about 4° and which were the same as those used by Sutherland (1954). In this experiment the after-effects were generally in a direction which would have been expected if apparent size determined the direction of the after-effect. In the interpretation of the results attention is drawn to the “Central Tendency Effect” which has been observed in size judgements of stimulus figures of varying size. Two hypotheses are suggested; one is that the true figural aftereffect has been obscured by the “Central Tendency Effect” in successive judgements, and the other is that time error in successive judgements of size is essentially a figural aftereffect. Some supportive evidence for the latter hypothesis is reported. It is concluded that apparent size is not a critical determinant of the figural after-effect.     

Attention and automaticity: Toward a theoretical integration

We sketch an initial version of a theory intended to account for the role of attention in the acquisition and expression of automaticity, and we test some initial predictions. The theory combines Logan's instance theory of automaticity and Bundesen's theory of visual attention, with Bundesen's theory determining what Logan's theory learns. We report four experiments that test the assumption that subjects learn what they report explicitly do not learn what they do not report explicitly. The experiments provide partial support for the predictions and encourage further development of the combined theory. Received: 4 September 1997 / Accepted: 12 January 1998     

The altered rationale for the choice of a standard animal in experimental psychology: Henry H. Donaldson, Adolf Meyer, and "the" albino rat

The mid 20th-century dominance of albino rats in nonhuman experimental psychology research often presumed that the animal embodied fundamental psychological processes that could generalize to a wide range of vertebrates. The author describes the conceptual basis for the original choice of white rats by the 2 individuals most responsible for establishing rats as a prominent animal model in the life sciences at the turn of the century: Henry H. Donaldson and Adolf Meyer. The author stresses the comparative rationale that justified their choice and argues that they sought generality through attention to diversity and species differences. Their approach contrasts sharply with the later view of the rat as a generic animal model that could represent similarities shared by all vertebrates. It is suggested that the change resulted from an emphasis on standardization produced by the growing industrialization of the life sciences in America.     

Judgments of perceptual groups: Reliability and sensitivity to stimulus transformation

The reliability of subjects’ judgments of the groups present in dot patterns and the sensitivity of those judgments to stimulus transformation were assessed. The subjects indicated the groups that they saw within random dot patterns, and each judgment was compared with those of other subjects and with their own judgments for related presentations. Within subjects, each pattern appeared in an initial presentation, an identical repetition, and a transformed state (a rotation or a change in scale). Witfiin-subjects judgments were more reliable than between-subjects judgments. An interpretation of within-subjects results was made in relation to predictions made by a formal algorithm of grouping by proximity (the CODE algorithm), which assumes that grouping by proximity is invariant over transformations such as rotations or changes in scale. A slight cost to transforming the patterns was found. The implications for CODE and for using grouping judgments as data are discussed.