THE VISUAL SYSTEM'S MEASUREMENT OF INVARIANTS NEED NOT ITSELF BE INVARIANT

Abstract— When two shapes that differ in orientation or size have to be compared or objects have to be recognized from different viewpoints, the response time and error rate art systematically affected by the size of the geometric difference. In this report, we argue that these effects are not necessarily solid evidence for the use of mental transformations and against the use of invariants by the visual system. We report an experiment in which observers were asked to give affine-invariant coordinates of a point located in an affine frame defined by three other points. The angle subtended by the coordinate axes and the ratio of the lengths of their unit vectors systematically affected the measurement errors. This finding demonstrates that the visual system's measurement of invariants need not itself be invariant.     

Remembering the levels of information in words

The qualitative nature of the incidental memory trace produced by perceptual and conceptual processing within a speeded inference task was examined. Performance on recall and auditory recognition tests replicated the general finding that semantic processing leads to better retention of words than does nonsemantic processing. This pattern of results was reversed on a visual recognition test designed to measure the amount of perceptual information remembered. These data suggest that different types of processing result in different aspects of the stimulus being encoded, with conceptual processing resulting primarily in the encoding of semantic information and perceptual processing resulting primarily in the encoding of physical information. Thus, the effectiveness of a particular kind of processing for good memory performance depends on the kind of information being tested.     

Training children's self-control: A field experiment in self-monitoring and goal-setting in the classroom

A field experiment investigated the effects of training in self-monitoring and goal-setting skills on classroom study behavior and academic achievement among elementary school students in an individualized mathematics program. In the Self-Monitoring Conditions, students were shown a simple system for observing and maintaining daily records of their own study behavior during their math classes; orthogonally, in the Goal-Setting Conditions, students were shown a simple method of setting and recording daily performance goals during their math classes. Exposure to self-monitoring procedures produced significant increases in both appropriate study behavior and in actual achievement in the mathematics program, while exposure to goal-setting procedures had no effect on either study behavior or academic achievement. Nor, contrary to expectation, did exposure to the goal-setting instructions enhance the effectiveness of the self-monitoring system. The implications of these results in terms of implicit and explicit models of self-reinforcement processes were discussed.     

Behavioral self-control in classroom settings: A review of the literature

Reviews the research on the use of behavioral self-control procedures with students in classroom settings. Thirteen published articles are reviewed. The three student classroom behaviors of on-task behavior, disruptive behavior, and academic behavior are considered. The use of behavioral self-control procedures appears promising with on-task and academic behaviors and inconclusive with disruptive behavior. The reviewed studies were weak regarding follow-up analyses and controlling for student prior experience with external contigency programs. Further research with behavioral self-control in different settings seems warranted.     

Alcohol breath tests: Criterion times for avoiding contamination by “mouth alcohol”

Using either a gas chromatography or an infrared absorption technique, series of blood alcohol concentrations (BACs) determined by breath tests were obtained from human subjects immediately subsequent to their having only oral contact with beverages ranging in ethyl alcohol concentration from 4% to 95% +. Times for total dissipation of mouth alcohol residuals to a level of practical nonsignificance ranged from 10 to 19 min. Dissipation rates were an inverse and approximately exponential function of the ethyl alcohol concentration of the beverage and were greatly shortened by rinsing the mouth with warm (34°C) water prior to testing. The results are discussed in terms of their relevance to the methodology of a number of research studies employing BAC breath-testing equipment.