Decisional processing in paranoid and non-paranoid schizophrenics

40 schizophrenic subjects, divided into paranoid/non-paranoid categories and 14 normal controls were presented a task which involved making "same-different" judgments during random presentations of a series of visual comparison stimuli with a standard which represented the midpoint of the stimulus continuum. Using Sternberg's Choice RT paradigm for studying the locus of cognitive deficit, difficulty at the response-selection stage was manipulated while holding other stages constant. It was predicted that paranoids would have shorter RTs at easy decision points and longer RTs at difficult decision points relative to non-paranoids. The directions of the differences were as predicted but did not attain statistical significance. Both schizophrenic groups, compared to normals, made significantly fewer "same" responses on those trials where the comparison and standard were most similar.     

Development of hand preference in the Colorado Adoption Project

A longitudinal study of the development of hand preference in 152 adopted and 120 nonadopted (control) infants measured in natural behavioral situations at both 12 and 24 mo. of age is reported. Significant developmental trends were observed for both increasing strength and direction of handedness. Less than 10% of the infants exhibited a clear preference at 12 mo. of age, whereas about 30% were lateralized at 24 mo., with more boys than girls being left-handed. In contrast, over 90% of the parents of these children (both biological and adoptive parents of the adopted children and parents of the nonadopted children) were lateralized. Perhaps because so few infants were lateralized at either age, parent-offspring resemblances were inconsistent and the number of significant parent/child correlations was about that expected on the basis of chance alone.     

Eye position and visual attention influence perceived auditory direction

The singular and joint effects of eccentric visual fixation and peripheral visual attention upon the perceived auditory median plane (PAMP) of the head were examined in four subjects. They positioned a hidden, horizontally-moving sound source to the perceived median plane of the head, while fixating a light 20 degrees or 45 degrees to the right or left of the actual median plane, and attending to another light in peripheral vision. Analysis by multiple linear regression yielded a model for each subject which indicated the nature and weighting of those factors contributing to variance reduction in PAMP judgments. Three subjects showed a strong linear attention effect, resulting in shifts of the PAMP away from the locus of attention. Similarly, a strong linear fixation effect was discovered in two subjects, a weak effect in another, and a nonlinear, inverse fixation effect in the last. Additional factors were noted for some subjects. Possible explanations of the observed effects were discussed. The study indicates that both visual attention and visual fixation are critical factors in experiments on auditory space perception although inter-individual differences do exist in the nature and strength of the effects.     

Short-term memory for colors and color names in the absence of vocalization

In a previous experiment, Allen found no release from proactive inhibition using the Brown-Peterson procedure in a group who were shifted from recalling colors to recalling the names of colors. The lack of release suggests that colors and color names are encoded in similar ways. It was argued that the similarity of encoding might have been caused by the procedure of requiring the subjects to say out loud the names of the colors at the time of stimulus presentation and recall. In the present experiment, a procedure was devised that eliminated the need for verbalization of the colors. The same pattern of results was obtained, namely, release from proactive inhibition in the group shifted from recalling color names to colors but not in the group shifted in the opposite direction. It was concluded that if subjects encode colors as a verbal label, then this encoding strategy is not caused by the procedure of requiring the subjects to verbalize the colors.     

A detailed study of sequential saccadic eye movements for normal- and poor-reading children

This paper presents the results of an in-depth study of parameters characterizing sequenced saccadic eye movements for a group of dyslexic children and a comparative normal control group with ages in the range greater than 8.0 yr. and less than 13.0 yr. No parameters were statistically different for the two groups, which supports the findings of Brown, et al. and contradicts the findings of Pavlidis. Our results indicate that sequenced saccadic eye movements are not diagnostically useful for early detection of dyslexia.