Kinetic subjective contours

Continuous changes in spatially separated figures can evoke perception of subjective contours and figures in physically homogeneous space between them. This occurs when all of the interruptions in the objectively present patterns (inducing elements) can be seen as caused by a unitary figure partly occluding them. Two experiments demonstrated and explored this phenomenon. In both, displays were presented to subjects under three conditions. In one condition, stationary inducing elements were shown as they would be interrupted by a figure rotating in front of them. In another condition, the background and inducing elements rotated, with interruptions occurring as if a stationary figure were in front. In a third condition, observers were shown 10 static views taken from the figure-rotation sequence for each display. Subjects consistently perceived unitary central figures with well-defined forms and clear edges from pattern changes given by figure movement and background movement. As with static subjective figures, kinetic subjective figures appear in front of, partly occluding, the inducing elements. These percepts form rapidly, and they depend upon temporal relations rather than upon information present in momentary views. Subjects occasionally reported subjective edges or a central figure in the stationary displays in Experiment 1, but not at all in Experiment 2, in which guessing tendencies were reduced by more specific instructions. The existence of kinetic subjective contours suggests that the visual system readily utilizes relationships among occlusion events separated in space and time. The minimum conditions for contour perception require neither information all along an edge nor simultaneous specification of the edge at two or more places.     

Quantifying the cognitive trajectories of extrapolated movements

Subjects' extrapolations of a piecewise constant-velocity trajectory and a constant-acceleration trajectory were mapped out over a sequence of trials that required only a button-press response. Without any performance feedback, subjects' extrapolations of both trajectories approximated an acceleration segment followed by a constant-velocity segment. With performance feedback, subjects' extrapolations of the constant-acceleration trajectory approached optimal performance. Subsequent withdrawal of the feedback shifted the entire extrapolated trajectory. These feedback-related changes in the extrapolated trajectory can be interpreted as changes in two parameters of a cognitive representation of the movement pattern.     

Speed of information processing and general intelligence

This study investigates the relationship between a number of measures of speed of cognitive information-processing and intelligence test scores. One hundred university students were given five tests of speed-of-processing, measuring their speed of encoding, short-term memory scanning, long-term memory retrieval, efficiency of short-term memory storage and processing, and simple and choice reaction time or decision-making speed. They were also given the Wechsler Adult Intelligence Scale and the Raven Advanced Progression Matrices. A number of multiple regression analyses show that the cognitive processing measures are significantly related to IQ scores. Other analyses indicate that this relationship cannot be attributed to the common content shared by the reaction time and the intelligence tests, nor to the fact that parts of the WAIS are timed. It is concluded that the reaction time tests measure basic cognitive operations which are involved in many forms of intellectual behavior, and that individual differences in intelligence can be attributed, to a moderate extent, to variance in the speed or efficiency with which individuals can execute these operations.     

A brief history of primary prevention in the twentieth century: 1908 to 1980

While primary prevention is a much talked about and debated topic in contemporary psychology, it has a considerable history. This paper critically traces primary prevention, philosophy and practice, in the 20th century. Beginning with the mental hygiene movement (1908-1960), the paper progresses to examine the child guidance movement (1920-1955), the eugenics movement (1860-1955), the initial era of federal involvement (1930s, 1940s) as well as significant research, events, and legislation in the decades between 1950 and 1980. The paper concludes with a synopsis of the major themes revealed by the review and suggestions for future efforts in prevention.     

Minor physical anomalies and obstetrical complications: Their relationship to hyperactive,psychoneurotic, and normal children and their families

Hyperactive, psychoneurotic, and normal control boys and their families were examined for minor physical anomalies (MPA). The results revealed that the hyperactive boys and their families had more MPA than the combined group of psychoneurotic and normal control children and their families. There were no differences in the mean number of MPA within families. Hyperactive probands also had more pre- and perinatal complications than the combined proband group. Furthermore, it was quite evident that the combination of numerous obstetrical complications and a high number of MPA significantly increased the probability of a child being diagnosed as hyperactive. The results are discussed in relation to the genetic transmission of MPA and the use of MPA as high risk indicators.     

Measuring human social perception directly

The perception of social behavior is direct when ecological correlates which specify a pattern are not manpulated. Spatial and temporal information appear to be two major correlates which facilitate human perception of ongoing social action. When these two correlates are disrupted in some fashion, the resulting action is ambiguous and its perception requires cognitive mediation on the part of the observers. The implications of these findings are discussed in relation to current social perception theory and research.