Practice effects for visual resolution in the periphery

Resolution thresholds at 0° (fovea), 20°, 40°, and 60° along the horizontal meridian of the temporal visual field revealed a characteristic degradation in visual resolution with increasing stimulus eccentricity. However, substantial individual differences were found, particularly at 40° and 60° of eccentricity. Dramatic improvements in peripheral visual resolution occurred over a period of 11 practice sessions, with the time course of practice effects increasing for greater visual field eccentricities. Improvements with practice reduced, but did not eliminate, individual differences. The present visual resolution findings are compared to previous studies of peripheral motion detection and increment thresholds.     

Development of an on-line problem-oriented system for the evaluation of mental health treatment services

Current on-line assessment applications are limited to mimicking instruments designed for paper and pencil. The development of an instrument designed specifically for on-line technology is described. The instrument provides research data on treatment effectiveness, clinical information for treatment planning, and management information for resource allocation.     

Effects of postresponse visual stimuli on visual discrimination learning in the rhesus monkey

To learn more about the mechanism (or mechanisms) involved with postresponse stimulus processing during discrimination learning, a series of studies was conducted with monkeys to determine why the combined relevant and irrelevant stimuli impair learning more than irrelevant stimuli appearing alone. It was found that: (a) the greater size and complexity of the combination of stimuli were not responsible for the greater deficit, while the presence of the relevant stimuli (S^D and S^Δ) within the stimulus combination apparently was; (b) the more similar the postresponse irrelevant stimuli were to the relevant stimuli the greater the deficit that resulted; and (c) monkeys that had earlier learned to discriminate the relevant and irrelevant features of a combination showed no learning impairment when this same stimulus combination was later presented after the response during a new learning problem. These results were interpreted as evidence that: (1) processes associated with learning a discrimination problem do not end with the execution of a choice response; (2) postresponse stimuli produce greater impairment in discrimination learning when they are distorted versions of the relevant stimuli; and (3) the impairment resulting from postresponse irrelevant stimuli occurs primarily when this misinformation is processed and misperceived as being relevant to learning the discrimination problem.     

Influence of linguistic complexity,rate of presentation,and interphrase pause time on auditory-verbal comprehension of adult aphasic patients

Among the variables affecting comprehension of linguistic stimuli by aphasic subjects are syntactic complexity and processing time. Comprehension performance of 15 aphasic adults was studied while altering the rate of speech presentation and varying the pause time between the major phrases within sentences of increasing grammatical complexity.Simple Active Affirmative Declarative Sentences, Negative, and Passive sentences were presented (1) at the rate of 150 words per minute (wpm) with 1-sec interphrase pause time (IPT); (2) 150 wpm with no pauses; (3) 120 wpm with 1-sec IPT; (4) 120 wpm with no pauses added.Performance was seen to vary with increasing syntactical complexity and as a function of processing time. Greater comprehension was seen with active affirmative than negative; greater with passive affirmative than with active negative. Clinical implications are discussed. Subjects demonstrated greater comprehension when sentences were presented at slower than normal rate; addition of interphrase pause time intervals aided comprehension. Combining slower rate of presentation and IPT intervals provided greatest increase in auditory processing time and showed concomitant increase in comprehension performance.