Binocular interaction of orientation and spatial frequency channels: Evoked potentials and observer sensitivity

The interaction between size and orientation feature processing in the human visual system was investigated. Both observer sensitivity (d’ss) and the visual evoked potential (VEP) to test gratings flashed to one eye were investigated as a function of the nature of a continuously presented suppressing grating viewed either by that same eye or the opposite eye. The test and suppressing gratings were varied both in bar width (9′ss vs. 36′ss) and orientation (vertical vs. horizontal). The continuous grating intra- and interocularly suppressed the monocular VEPs to the flashed grating, the specificity of the suppression depending on the latency at which VEP amplitude was measured. VEP amplitude measured at early latencies (100–125 msec) was suppressed primarily when the flashed and continuous gratings were the same orientation, regardless of size. Starting at about 200 msec, and thereafter, VEP amplitudes were suppressed when the continuous bars were either the same orientationor size as the flashed bars. Late latencies, starting at 220 msec, and thereafter, were suppressed primarily when the bars in the two gratings were the same orientation and size. The reduction in observer sensitivity (d′ss) paralleled the changes found in the late VEP measures. These effects were evident under both the intraocular and interocular suppressing conditions. This pattern of VEP suppression, measured across eight points in the VEP waveform, was interpreted as indicating the existence of a sequence of channels that are specific first to a particular grating orientation, then to either a particular grating spatial frequency or orientation, and finally to the conjunction of a particular orientation and spatial frequency. Both sequential and parallel feature processing appears to take place in the human visual cortex, with grating orientation being encoded earlier than grating size.     

Size,convexity, and curvature magnitude estimations of curvilinear forms

Groups of Os made magnitude estimates of size, convexity, and curvature of patterns along a shape continuum. College Os repeated the procedure for a given physical measure in three successive sessions, but high school Os made only one set of estimates. The apparent size for the patterns was found to grow with an exponent between .700 and .755 for high school and college Os. The magnitude estimates for convexity and curvature were less reliable than the size estimates both between college and high school Os and within college Os over successive sessions. The magnitude estimates from the high school and college Os showed a faster apparent growth of curvature than of convexity.     

Learning and understanding

Short texts containing rather difficult pieces of logical argument were presented, sometimes with illustrative graphs and sometimes without, to girls from the sixth form of a grammar school. They were required to study these, and recall afterwards what they were about. It was found that frequently there was a comparatively accurate recall of many of the individual items of the texts, but that certain essential points in the argument were omitted. Thus learning of detail could occur when there was no general understanding of the meaning. The effect of the illustrative graphs was to make the recalls even less coherent.     

Comparative Effectiveness of Student and Professional Counselors

A sample of 160 beginning freshmen, half males and half females, received six and one-half hours of academic adjustment guidance from same-sex professional counselors. Upperclassman student counselors gave equivalent guidance to all other beginning freshmen at Southwest Texas State College. A matching sample of 80 men and 80 women was subsequently drawn from the 316 freshmen receiving student-to-student counseling. Age, sex, measured scholastic ability, measured study orientation, and high school academic achievement were employed as matching variables. The four professional and eight student counselors completed 50 clock hours of identical pre-counseling training, used identical guidance materials, and followed identical counseling activity sequences. Equivalent counseling facilities were provided for all counselors. Test, questionnaire, and scholarship data were employed to evaluate the comparative effectiveness and acceptability of counseling given the professional counseled and the student counseled groups. Student counselors were found to be as effective as professional counselors on all criteria of counseling effectiveness. Furthermore, freshmen counseled by student counselors made significantly greater use of the information received during counseling, as reflected by first-semester grades and residual study problems. It was concluded that carefully selected, trained, and supervised student counselors provide a practical and productive addition to the college's guidance program.     

Reaction times and speed-of-processing: Their relationship to timed and untimed measures of intelligence

Eighty-one university students were given a battery of reaction time tests, measuring the speed with which they performed various elementary cognitive processes, and a group test of intelligence which yielded timed and untimed scores. Multiple regression analyses indicated that speed of information-processing was an equally good predictor of timed and untimed intelligence test performance, and that various combinations of speed-of-processing variables accounted for as much as 48% of the variance in intelligence test scores. Different speed-of-processing variables varied relatively systematically in the extent to which they correlated with the individual subtests and scales of the intelligence test.     

Crisis prevention and intervention training for psychiatric hospital staff

A 5-day course designed to train psychiatric hospital staff verbal and physical methods of preventing violence and injury when dealing with upset patients was taught to 89 staff from maximum and less secure wards. Compared to no-treatment controls, experimental subjects improved significantly on four tests of crisis-related tests and knowledge. Questionnaire and self-report measures from staff and patients on the training wards also indicated positive course effects. Assault frequencies decreased immediately after the course and staff injuries on experimental wards were reduced after the course relative to control wards.     

The effects of signalled and unsignalled lick-dependent delays on the development of schedule-induced drinking in rats

Food pellets were programmed to be delivered to rats every 60 sec (Fixed Time 60-sec schedule), and the development of schedule-induced drinking was measured in terms of the amount of water consumed and the number of licks per inter-pellet interval. For some rats (masters) 10-sec delays in food delivery were dependent on licks. Yoked-control rats received food at the same time as their masters and independently of their own behaviour. In Experiment 1, in which the delays were signalled by a blackout, the master rats began to drink, but this schedule-induced behaviour then decreased to levels lower than those shown by the yoked controls. When the signalled delays were discontinued, the drinking of the master rats recovered. In Experiment 2, in which the delays were not signalled, the master rats did not develop as much schedule-induced drinking as the yoked controls, and discontinuing the delays led to only small increases in drinking. These results support the view that schedule-induced drinking is subject to control by its consequences.