Helen C. Beh

Performance on driving-related tasks during music

The effect of music on driving-related tracking and vigilance tasks was examined. Participants carried out the tasks either singularly (low demand) or together (high demand) under conditions of silence, low-intensity music of high intensity music. The results indicated that while the relatively simple tracking task was not affected by the music, response time to centrally located visual signals was improved under both music conditions and under both low- and high-demand situations. High-intensity music was associated with an increase in response time to peripheral signals under high-demand conditions. The results are discussed in relation to increased selectivity of attention with music-induced arousal.

Hick's Law, Competing-Task Performance, and Intelligence.

Abstract In recent times, psychologists have attempted to relate individual differences in intelligence either to differences in a subjects ability to divide attention or to differences in the speed with which they process the information offered by the environment. Because these approaches are not mutually exclusive and, indeed, have some important features in common, it was decided to examine the relationship between speed of processing and intelligence under conditions requiring divided attention. To this end, the Ravens Standard Progressive Matrices Test was administered to 48 subjects who subsequently performed a card-sorting task of varying information content under both single- and competing-task conditions. The obtained results point strongly to a more central role for complexity in speed of processing models of intelligence.

Component Analysis of Orientation Illusions

Orientation illusions occur when the inducing figure is a line or grating (the tilt illusion) or a square outline frame (the rod-and-frame illusion). In the range of inducing figure tilts between vertical and horizontal, the tilt illusion describes one cycle of positive (direct) and negative (indirect) effects but the rod-and-frame illusion describes two such cycles. In two experiments, angular functions of illusions were measured with the six possible inducing figures which result when two of the four sides of a square inducing frame are deleted. As expected, the parallel-sided frame amputations induced angular functions similar to the tilt illusion and these functions differed from those induced by the orthogonal-sided amputations. In agreement with previous findings on the nonadditivity of tilt illusions, the sum of angular functions induced by frame amputations, which together form a complete frame, were not always equivalent to the angular function induced by a complete frame, and there were asymmetries in the data for which neither of two simple hypotheses could adequately account. The discussion focuses upon properties of inducing figures which psychophysical hypotheses might need to consider in order to account for the shapes of angular functions of orientation illusions and, in particular, a distinction is drawn between the global orientation of the inducing figure and the orientations of its (local) component features. It is suggested that it might be fruitful if the tilt illusion and the rod-and-frame illusion were conceived of as illusions resulting from inducing figures composed of all or part of n gratings of spatial frequency fn intersecting at angles of 180°/n.

Theangular function of arod-and-frame illusion

It was predicted that vertical settings of a rod surrounded by a square frame would be in error in the direction of the frame axis closest to true vertical as the frame varied in tilt. Results were in accord with this hypothesis. The implications of the results are discussed.

Evidence for an attentional model of human intelligence using the competing task paradigm

Abstract The present study examined competing task performance within an information theory framework. In the first experiment, 72 subjects performed a card-sorting task at four levels of task difficulty (0-bit, 1-bit, 2-bit and 3-bit levels) under both single and competing task conditions. Output per 60 sec was measured for each task. In the second experiment, estimates of fluid and crystalized ability, as well as short-term acquisition and retrieval, were obtained from 68 subjects who performed the same tasks as the subjects in Experiment 1. The results of the first experiment suggested the rate of processing remains invariant under both single and competing task conditions with the latter condition being readily interpreted as introducing an additional bit of information. The introduction of the competing condition also led to higher correlation between processing parameters and Gf (but not Gc or SAR) marker tests. The implication of these findings for cognitive models of human ability is discussed.

Perceptual distortion of an oblique line in the presence of an abutting vertical line

Abstract Two experiments measured line-dot alignment errors to either a long (2 deg 6 min) or short (12.7 min) oblique test line which was presented either in isolation or abutting a vertical inducing line. Alignment PSEs were obtained for a variety of line-dot separations at both the free end and at the intersect end of the test line, using a multiple randomly interleaved staircase technique. A number of aspects of the data were inconsistent with the hypothesis that alignment errors reflect whole-of-line changes in perceived orientation or intercept when the inducing line is present. Rather, the results were consistent with the notion that long lines are processed by integrating the outputs of analysers which respond to short line segments and that alignment errors reflect the differential weighting given to such analysers, depending upon the distance between the dot and the relevant segment of the line. An alternate hypothesis involving “cognitive mistracking” (Tong and Weintraub, 1974) could not be excluded by the results.

Effect of Long Flights on the Cognitive Performance of Air Crew

The cognitive performance of groups of subjects was tested after flights lasting between 7.5–9.5 hours to the north, east and west of Sydney (ns = 10, 12, and 12) and compared with the performance of a ground-based control group (n = 12). Analysis showed an impairment in performance of the flight groups following the flights. The analysis suggests that part of the performance change following transzonal flights may result from stress induced during the flight rather than adjustment to new time zones.

Alignment errors to both ends of acute- and obtuse-angle arms.

It has been reported that errors which occur in attempts to align the arms of two acute angles differ in size and direction from errors which occur when the angles are obtuse (Restle, 1969). Other experiments have qualified this conclusion, and it has been suggested that Restle’s result was dependent on the use of a forced-choice method with a dual-angle display (Day, 1973). Data are reported here on dot-to-line misalignments using staircase techniques both at the free end and at the vertex end of single acute or obtuse angles. The results essentially agree with Day’s method-of-adjustment results, thus implicating the display rather than the method as the cause of the original negative acute-angle effect. However, Day found no difference between the acute-angle effect and the parallelless Poggendorff illusion, while we did obtain a difference under some conditions. Consideration of the magnitudes and directions of errors at both ends of the angles’ arms gives pause to any possible accounts of the errors in terms of simple or single whole-of-line effects.

The effect of variation of frame shape on the angular function of the rod-and-frame illusion

The angular function of the rod-and-frame illusion was studied under conditions of variation in frame shape. The results support predictions arising from the hypothesis that as a frame is varied in tilt, vertical settings of a rod will be in error in the direction of the major frame axis closest to true vertical.

Achievement motivation, performance and cardiovascular activity.

Cardiovascular measures were obtained from 40 subjects differing in level of achievement motivation during the performance of a vigilance task. Analysis of interbeat interval and heart rate variability indicated that cardiovascular measures obtained from low achievers did not differ significantly from pre-test measures during the performance of the task, while the measures from high achievers did. In addition, the performance of high achievers was significantly better than the performance of low achievers. It is suggested that these findings indicate that high achievers are marked by the effort they expend in performance and that such effort is reflected in the cardiovascular activity of such subjects.