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Biomedical subjects

G Chastain

Publications and source records attributed to G Chastain.

47 records · Page 3Linked to original sources
PubMed1982

Asymmetric parafoveal interference with dichoptic presentations.

A Landolt C target and letter X nontarget were dichoptically presented to 8 subjects. The nontarget presented to one eye foveally or peripherally flanked the area of the parafovea corresponding to that receiving the target in the other eye. Identification of the orientation of the C was poorer with the nontarget in the peripheral position. If, as has been proposed previously, asymmetric lateral inhibition is responsible for the phenomenon, its locus would seem to lie beyond the retina.

Form Perception↗
PubMed1977

Feature analysis and the growth of a percept.

Twelve trigrams divided into four sets, the members of each set varying systematically in the feature configuration at each letter position, were repeatedly exposed at brief durations in a random order to subjects who were asked to report after each exposure those letters that could be recognized with certainty. The set of three trigrams that had the same features for all letters in a given ordinal position was identified with fewer exposures than were necessary to permit identification of sets for which the featural characteristics varied within a spatial position. The results were interpreted as being consistent with a constructive model of letter recognition in which the observer tests hypotheses regarding the presence of a given letter based on the presence of relevant features in a spatial position.

Discrimination, Psychological↗
PubMedDate not supplied

Facilitatory or inhibitory nontarget effects in the location-cuing paradigm.

The effect of nontargets on the identification of targets in the location-cuing paradigm was investigated in order to determine whether observers consistently allocate their attention to a validly cued location and whether the effect of nontargets is to facilitate or to inhibit performance. In four experiments, the effects of a single matching nontarget or a single nonmatching nontarget were compared. In each experiment, it was shown that observers consistently allocate their attention to a cued location when a precue appears and that performance is inhibited more by nonmatching nontargets in the display than it is facilitated by matching nontargets.

Adult↗