Aging and the detection of observer and moving object collisions

The authors examined age-related differences in the detection of collision events. Older and younger observers were presented with displays simulating approaching objects that would either collide or pass by the observer. In 4 experiments, the authors found that older observers, as compared with younger observers, had less sensitivity in detecting collisions with an increase in speed, at shorter display durations, and with longer time-to-contact conditions. Older observers also had greater difficulty when the scenario simulated observer motion, suggesting that older observers have difficulty discriminating object motion expansion from background expansion from observer motion. The results of these studies support the expansion sensitivity hypothesis-that age-related decrements in detecting collision events involving moving objects are the result of a decreased sensitivity to recover expansion information.     

Possible barnum effect in the five factor model: do respondents accept random neo personality inventory-revised scores as their actual trait profile?

This study investigated a possible Barnum effect in personality traits, i.e., that persons accept a false trait profile as correct. Having answered the Norwegian translation of the NEO Personality Inventory-Revised, a group of 75 students, 56 (five women military aviation cadets and 19 (10 women) graduate students, received a random T-score profile and were asked to rate their agreement on a 7-point scale. For all personality traits, i.e., facets and domains measured by the NEO Personality Inventory-Revised, positive correlations ranging from .08 to .64 were found between the agreement ratings and the similarity between the random false scores and the actual scores. The respondents identified and rejected random T scores that deviated far from their actual scores, which works against the Barnum effect. Correct identification correlated negatively with Neuroticism r = -.41) and positively (r = .53) with Conscientiousness.     

Necessity of spatial pooling for the perception of heading in nonrigid environments

This study examined whether the perception of heading is determined by spatially pooling velocity information. Observers were presented displays simulating observer motion through a volume of 3-D objects. To test the importance of spatial pooling, the authors systematically varied the nonrigidity of the flow field using two types of object motion: adding a unique rotation or translation to each object. Calculations of the signal-to-noise (observer velocity-to-object motion) ratio indicated no decrements in performance when the ratio was .39 for object rotation and .45 for object translation. Performance also increased with the number of objects in the scene. These results suggest that heading is determined by mechanisms that use spatial pooling over large regions.     

Cognitive efficiency on a match to sample task decreases at the onset of puberty in children

Electrocortical evidence indicates that a wave of synaptic proliferation occurs in the frontal lobes around the age of puberty onset. To study its potential influence on cognition, we examined 246 children (10-17 years) and 49 young adults (18-22 years) using a match-to-sample type of task to measure reaction times to assess emotionally related information. Based upon the instruction set, subjects made a yes/no decision about the emotion expressed in a face, a word, or a face/word combination presented tachistoscopically for 100 ms. The faces were images of a single individual with a happy, angry, sad or neutral expression. The words were 'happy,' 'angry,' 'sad,' or 'neutral,' In the combined stimulus condition, subjects were asked to decide if the face and word matched for the same emotion. Results showed that compared to the previous year, reaction times were significantly slower for making a correct decision at 11 and 12 years of age in girls and boys, the approximate ages of puberty onset. The peripubertal rise in reaction time declined slowly over the following 2-3 years and stabilized by 15 years of age. Analyses of the performance of 15-17 year olds revealed significantly longer reaction times in females to process both faces and words compared to males. However, this sex difference in late puberty appeared to be transient since it was not present in 18-22 year olds. Given the match-to-sample nature of the task employed, the puberty related increases in reaction time may reflect a relative inefficiency in frontal circuitry prior to the pruning of excess synaptic contacts.     

Perceived depth of 3-D objects in 3-D scenes

Effects of information specifying the position of an object in a 3-D scene were investigated in two experiments with twelve observers. To separate the effects of the change in scene position from the changes in the projection that occur with increased distance from the observer, the same projections were produced by simulating (a) a constant object at different scene positions and (b) different objects at the same scene position. The simulated scene consisted of a ground plane, a ceiling plane, and a cylinder on a pole attached to both planes. Motion-parallax scenes were studied in one experiment; texture-gradient scenes were studied in the other. Observers adjusted a line to match the perceived internal depth of the cylinder. Judged depth for objects matched in simulated size decreased as simulated distance from the observer increased. Judged depth decreased at a faster rate for the same projections shown at a constant scene position. Adding object-centered depth information (object rotation) increased judged depth for the motion-parallax displays. These results demonstrate that the judged internal depth of an object is reduced by the change in projection that occurs with increased distance, but this effect is diminished if information for change in scene position accompanies the change in projection.     

Pursuit compensation during self-motion

The pattern of motion in the retinal image during self-motion contains information about the person's movement. Pursuit eye movements perturb the pattern of retinal-image motion, complicating the problem of self-motion perception. A question of considerable current interest is the relative importance of retinal and extra-retinal signals in compensating for these effects of pursuit on the retinal image. We addressed this question by examining the effect of prior motion stimuli on self-motion judgments during pursuit. Observers viewed 300 ms random-dot displays simulating forward self-motion during pursuit to the right or to the left; at the end of each display a probe appeared and observers judged whether they would pass left or right of it. The display was preceded by a 300 ms dot pattern that was either stationary or moved in the same direction as, or opposite to, the eye movement. This prior motion stimulus had a large effect on self-motion judgments when the simulated scene was a frontoparallel wall (experiment 1), but not when it was a three-dimensional (3-D) scene (experiment 2). Corresponding simulated-pursuit conditions controlled for purely retinal motion aftereffects, implying that the effect in experiment 1 is mediated by an interaction between retinal and extra-retinal signals. In experiment 3, we examined self-motion judgments with respect to a 3-D scene with mixtures of real and simulated pursuit. When real and simulated pursuits were in opposite directions, performance was determined by the total amount of pursuit-related retinal motion, consistent with an extra-retinal 'trigger' signal that facilitates the action of a retinally based pursuit-compensation mechanism. However, results of experiment 1 without a prior motion stimulus imply that extra-retinal signals are more informative when retinal information is lacking. We conclude that the relative importance of retinal and extra-retinal signals for pursuit compensation varies with the informativeness of the retinal motion pattern, at least for short durations. Our results provide partial explanations for a number of findings in the literature on perception of self-motion and motion in the frontal plane.     

The Second Essential Tension: on Tradition and Innovation in Interdisciplinary Research

In his analysis of “the essential tension between tradition and innovation” Thomas S. Kuhn focused on the apparent paradox that, on the one hand, normal research is a highly convergent activity based upon a settled consensus, but, on the other hand, the ultimate effect of this tradition-bound work has invariably been to change the tradition. Kuhn argued that, on the one hand, without the possibility of divergent thought, fundamental innovation would be precluded. On the other hand, without a strong emphasis on convergent thought, science would become a mess created by continuous theory changes and scientific progress would again be precluded. On Kuhn’s view, both convergent and divergent thought are therefore equally necessary for the progress of science. In this paper, I shall argue that a similar fundamental tension exists between the demands we see for novel insights of an interdisciplinary nature and the need for established intellectual doctrines founded in the classical disciplines. First, I shall revisit Kuhn’s analysis of the essential tension between tradition and innovation. Next, I shall argue that the tension inherent in interdisciplinary research between, on the one hand, intellectual independence and critical scrutiny and, on the other hand, epistemic dependence and trust is a complement to Kuhn’s essential tension within mono-disciplinary science between convergent and divergent thought.     

Self-ratings of positive and negative affect and retrieval of positive and negative affect memories

Abstract

Based on analysis of self-ratings of mood, positive affect (PA) and negative affect (NA) have been proposed as basic, orthogonal mood dimensions (Watson & Tellegen, 1985). The present study asked subjects (N = 61) to not only provide self-ratings of PA and NA terms but also to retrieve personal memories associated with those terms. Self-rated PA was associated with latency to retrieve PA- but not NA-related memories; self-rated NA was associated with latency to retrieve NA- but not PA-related memories. Self-ratings of PA and NA were not significantly correlated, nor were retrieval latencies for PA and NA memories. Individual item correlations also revealed a strong direct relationship between self-ratings and retrieval latency. The dissociations involving a non-self report measure strengthen the distinction between PA and NA, and the individual item correlations are interpreted as showing that self-ratings of affect are based upon the ease of retrieval of personal memories.