A new method for determining the personal constants in the Luneburg theory of binocular visual space

Based on the Luneburg theory of binocular visual space, the equation for a visual circle (an apparent circle) was derived to estimate the personal constants, o and K, in this theory. Using small points of light in an otherwise dark room, five observers were asked to construct a visual circle on the horizontal plane with a standard radius of 50 or 100 cm in the median plane. The observation distance for the small circle was 250, 450, or 700 cm, and that for the large circle was 700, 1,030, 1,300, or 1,600 cm. The personal constants calculated from the radii of six directions in each circle were found to be inconsistent with those expected from this theory. The os obtained were remarkably larger than those observed in earlier studies and increased systematically as the observation distance increased. Almost all Ks were negative, with most being less than minus one. Possible factors responsible for these inconsistencies are discussed with reference to the results of previous experiments.     

A new argument for the phenomenal approach to personal persistence

Philosophical Studies - When it comes to personal identity, two approaches have long ruled the roost. The first is the psychological approach, which has it that our persistence through time...     

A dilemma for the soul theory of personal identity

The problem of diachronic personal identity is this: what explains why a person P₁ at time T₁ is numerically identical with a person P₂ at a later time T₂, even if they are not at those times qualitatively identical? One traditional explanation is the soul theory, according to which persons persist in virtue of their nonphysical souls. I argue here that this view faces a new and arguably insuperable dilemma: either (a) souls, like physical bodies, change over time, in which case the soul theory faces an analogue problem of diachronic soul identity, or (b) souls, unlike physical bodies, do not change over time, in which case the soul theory cannot explain why souls relate to particular bodies over time and so at best only partially explains personal identity. I conclude that the soul theory fares no better than physicalist-friendly accounts of personal identity such as bodily- or psychological-continuity-based views.     

Autobiographical fluency: A method for the study of personal memory

Fifty-five subjects recalled autobiographical episodes or personal facts such as names of friends and teachers, from different lifetime periods. In each case, subjects were given 90 sec in which to retrieve as many items as possible. Also tested was subjects' fluency in generating items from semantic categories (animals, vegetables, British prime ministers, and U.S. presidents). Results of cluster analysis on the fluency tasks showed a dissociation between subjects' ability to retrieve personal episodes, personal semantic information, and nonpersonal semantic information. The dissociations observed in the fluency tasks are interpreted in terms of the different retrieval strategies required for the different types of information sought.     

Mapping visual attention with change blindness: new directions for a new method

Change blindness provides a new technique for mapping visual attention with unprecedented spatial and temporal resolution. Change blindness can occur when a brief full-field blank interferes with the detection of changes in a scene that occur during the blank. This interference can be overcome by attending to the location of a change. Because changes are detected at attended locations, but not at unattended locations, detection accuracy provides an indirect measure of the distribution of visual attention. The likelihood of detecting a new element in a scene provides a measure of the occurrence of attention at that element’s location. Potential new directions, advantages, and problems with this method are considered.     

Enumerating by pointing to locations: a new method for measuring the numerosity of visual object representations

The fast and accurate enumeration of a small set of objects, called subitizing, is thought to involve a different mechanism from other numerosity judgments, such as those based on estimation. In this report, we examine the subitizing limit using a novel enumeration task that obtained the perceived locations of enumerated objects. Observers were shown brief masked displays (50, 200, and 350 ms) of 2-9 small black discs randomly placed on a gray screen and then asked to place a marker where each disc had been located. The number of these markers provided an estimate of the number of items processed. This "pointing" methodology enabled observers to accurately "enumerate" displays containing up to six items in contrast with the four-item limit typically found when using standard reporting methods (and replicated here in Experiment 2). These results suggest a different account of the limits found in most subitizing and enumeration studies.     

Erratum to: Voluntary action alters the perception of visual illusions

Attention, Perception, & Psychophysics -     

A new approach to the generation of visual stimuli for eye-movement research

An interactive, computer-controlled, visual stimulus generator is described, suitable for both psychophysical and neurophysiological experimentation on human subjects. The system core is a wide-screen electrostatic cathode-ray tube, which can be used both as a television monitor, to display standard video pictures, and as anx-y oscilloscope, so that a bright dot can be moved around the display by electrical signals. In addition, a third working mode is provided, according to which a time-compressed video picture of limited size (fast picture) plays the role that is typical of the spot in a standard oscilloscope. Through computer-assisted time compression, the frame period of the video signal is reduced to about one tenth of its standard value. The fast picture can accordingly be driven by even the fastest eye movements, and it can be displayed as a stabilized image, or, more generally, in the altered retinal feedback condition. Moreover, as compared with a standard video picture, the fast image can be “flashed” over much shorter time periods. Since a standard input video signal is used for both standard and fast video pictures, all the image processing facilities of commercial videographic systems can be fully exploited by the proposed device.     

Perfectionism and the pursuit of personal goals: A self-determination theory analysis

Previous studies have shown that self-critical and personal standards forms of perfectionism are associated with progress on personal goals in opposite ways. The present study used a 5-wave prospective longitudinal design to examine what motivational factors account for the finding that self-critical perfectionism has been reliably associated with poor goal progress whereas personal standard perfectionism has been associated with good progress. Specifically, we adopted a self-determination theory perspective to examine the role of autonomy in mediating the effects of perfectionism. Our results replicated previous findings linking the two forms of perfectionism with opposite patterns of goal progress. Importantly, the results suggested that the negative goal effects of self-critical perfectionism are mediated by lower levels of autonomous goal motivation. The results also demonstrated links from personal standards perfectionism to greater autonomous goal motivation. Interestingly, the effects of self-critical perfectionism on goal progress appeared to be dynamic over time and implicated affective mechanisms. The results of the investigation point to the value of adopting a self-determination theory perspective to understand perfectionism.     

Validating a new method for quantifying traits: The computer-administered visual analog

This article introduces a new method for assessing personality traits that uses graphic rather than written items to facilitate the convergent validation of personality traits. A computer-administered visual analog procedure is presented that samples 40 equally spaced positions along a trait continuum five times. Examinees initiate each trial by pressing the space bar and end it by pressing either a “True” or “False” key indicating if that location describes them or not. Response time is measured in milliseconds. The majority answer determines the aggregate response and the median response time determines the latency for the aggregate response to each location on the trait continuum. This procedure enables an empirical measure of trait variability. Results indicated theoretically meaningful responses in 94 college students on each of two personality dimensions; extraversion and trait anxiety. The predicted inverted-U function was obtained for both personality dimensions such that the fastest response times were associated with 0 and 5 “True” responses, somewhat longer response times were associated with 1 and 4 “True” responses, and the longest times were associated with 2 or 3 “True” responses. Statistically significant and substantial validity coefficients were obtained with the Eysenck personality inventory extraversion scale, and the state-trait anxiety inventory, form Y-2.