Focusing attention on overlapping and non-overlapping figures with subjective contours

In a series of five experiments we investigated whether observers could focus attention on a restricted visual area that was demarcated by Kanizsa-like subjective contours, and whether this effect also occurred in the case of overlapping figures. The task was a simple reaction time to a luminance increment and the basic finding was that reaction time was faster when the imperative stimulus fell inside the focus of attention than when it fell outside. The first two experiments showed that the extent of the attentional focus could be adapted to a region that was demarcated by subjective contours, thus extending the results of previous studies that used regions demarcated by real contours. The last three experiments showed that, regardless of the type of margins, focusing was more efficient for the figure that was perceived as lying in front in a pair of overlapping figures. Received: 21 December 1999  / Accepted: 23 August 2000     

Object recognition contributions to figure-ground organization: Operations on outlines and subjective contours

In previous research, replicated here, we found that some object recognition processes influence figure-ground organization. We have proposed that these object recognition processes operate on edges (or contours)detected early in visual processing, rather than on regions. Consistent with this proposal, influences from object recognition on figure-ground organization were previously observed in both pictures and stereograms depicting regions of different luminance, but not in randomdot stereograms, where edges arise late in processing (Peterson & Gibson, 1993). In the present experiments, we examined whether or not two other types of contours—outlines and subjective contours—enable object recognition influences on figure-ground organization. For both types of contours we observed a pattern of effects similar to that originally obtained with luminance edges. The results of these experiments are valuable for distinguishing between alternative views of the mechanisms mediating object recognition influences on figure-ground organization. In addition, in both Experiments 1 and 2, fixated regions were seen as figure longer than nonfixated regions, suggesting that fixation location must be included among the variables relevant to figure-ground organization.     

The effects of perceptual set on the shape and apparent depth of subjective contours

Two experiments showed the influence of perceptual set on the perception of subjective contours. In the first, the perceived shape of a subjective-contour figure (a minimal version of the Ehrenstein configuration) was varied by altering the observer’s viewing set. The second experiment showed that apparent depth emerged in subjective-contour figures when observers were set to perceive the illusory contours.     

The effects of illumination level and retinal size on the apparent strength of subjective contours

The apparent strength of subjective contours was investigated as a function of illumination level, figure size, and viewing distance. Magnitude estimation, with a real contour standard as the modulus, was used to measure the perceived strength of the illusory contours. It was found that illumination level and retinal size are both powerful determinants of the apparent strength of subjective contours, generating magnitude estimates varying from 20% to 96% of the strength of the real contour modulus. Particularly strong subjective contours were reported for figures of small retinal size (1.2 to 4.8 deg) under very dim illumination (.10 log lx).     

Another look at the effect of a surprising intervening event on negative priming.

Tipper et al. (1991) reported that negative priming is eliminated when a low-probability event separates presentation of the prime display from the probe display. This finding is perfectly consistent with at least three of the major accounts of negative priming. However, each of these accounts can reasonably be argued to make different predictions regarding the effect of a surprising intervening event on attended repetition effects. The purpose of the experiment reported here was to determine which of these three predictions was correct. The results obtained were consistent with none of the three predictions. The low-probability intervening event did eliminate negative priming, but did so by slowing performance in the baseline condition relative to all other conditions. The results are discussed with respect to the role of surprise in responding to novel events.     

Examining a negative halo effect to anabolic steroids users through perceived achievement goals,sportspersonship orientations,and aggressive tendencies

We investigated the social image of anabolic steroids (AS) users grounding our analysis on the achievement goal theory of Nicholls. Our main goal was to explore how an athlete’s acceptance of AS use would impact on the way that athlete will be perceived by others. Non‐AS‐using participants reacted to one of two scenarios portraying a male athlete either accepting or refusing to engage in drug use behavior. The results suggested that the acceptance of anabolic steroids yielded an unfavorable social image – perceivers inferred a predominant ego orientation to characterize the AS‐user’s motivation as well as weaker sportspersonship and a stronger proclivity for reactive aggression than instrumental aggression. Moreover, the analyses did not yield significant gender or interaction effects. Finally, those findings are commented in view of methodological shortcomings and of the perspectives that they may offer for future research concerning the motivational aspects of the social perceptions of drug use in sport.     

The effect of accent evaluation and evidence on a suspect's perceived guilt and criminality

The authors investigated the effect of accent evaluation, evidence, and crime type on participants' perceptions of guilt and criminality. British student raters (n = 199) listened to a tape-recorded exchange between a male criminal suspect and a male policeman. The authors manipulated this exchange to produce a 2 (accent type: English regional or standard) x 2 (evidence type: strong or weak) x 2 (crime type: blue collar or white collar) factorial design. Dependent measures consisted of participants' ratings of the suspect's guilt and criminality. Contrary to previous research, accent did not significantly influence attributions of guilt either as a main effect or in interaction with the contextual variables. However, independent of evidence presented and crime type, the regional-accented suspect was evaluated as more typically criminal and more likely to be reaccused of a crime than the standard-accented suspect.     

The effect of visual magnification and reduction on perceived hand size

The aim of the present study was to clarify the mechanisms underlying body understanding by examining the impact of visual experience (magnification and reduction) on perception of hand size and neutral external objects (squares). Independent groups of participants were asked to look through a 2× magnification lens, a ½-× reduction lens, or a control UV filter and to make visual size judgments about square stimuli and their hands. In Experiment 1, participants used a measuring device with unmarked wooden slats orientated in horizontal and radial/vertical space for their visual judgments. In Experiment 2, participants used an upright frontal slat for visual length judgments of their hands to eliminate any potential foreshortening in viewing the measurement apparatus. The results from the two experiments demonstrate that participants significantly underestimated both the square stimuli and their hands when they viewed them under a reduction lens. While overestimation and underestimation of squares was found for females in Experiment 2, males generally underestimated the squares. However, overestimation was not seen when the participants viewed their hands under a magnification lens. Implications of these findings are discussed.     

Birth order has no effect on intelligence: a reply and extension of previous findings

We address points raised by Zajonc and Sulloway, who reject findings showing that birth order has no effect on intelligence. Many objections to findings of null birth-order results seem to stem from a misunderstanding of the difference between study designs where birth order is confounded with true causal influences on intelligence across families and designs that control for some of these influences. We discuss some of the consequences of not appreciating the nature of this difference. When between-family confounds are controlled using appropriate study designs and techniques such as multilevel modeling, birth order is shown not to influence intelligence. We conclude with an empirical investigation of the replicability and generalizability of this approach.     

Body tilt effect on the reproduction of orientations: studies on the visual oblique effect and subjective orientations

Body tilt effects on the visual reproduction of orientations and the Class 2 oblique effect (E. A. Essock, 1980) were examined. Body tilts indicate whether the oblique effect (i.e., lower performance in oblique orientations than in vertical-horizontal orientations) is defined in an egocentric or a gravitational reference frame. Results showed that the oblique effect observed in upright posture disappeared in tilted conditions, mainly due to a decrease in the precision of the vertical and horizontal settings. In tilted conditions, the subjective visual vertical proved to be the orientation reproduced the most precisely. Thus, the oblique effect seemed to be not purely gravitationally or egocentrically defined but, rather, to depend on a subjective gravitational reference frame tilted in the same direction as body tilts.     

The effect of CS-US contingency variation on GSR and on subjective CS-US relational awareness

Ninety subjects were tested in a single-cue Pavlovian conditioning paradigm involving three groups which differed with regard to the contingency relationship between CS and US (negative contingency, zero contingency, positive contingency). To examine the relationship between conditioned GSR performance and subject’s cognitive beliefs regarding the CS-US relationship, both GSR and CS-US relational learning were constantly measured on a continuous scale over the entire experimental session. The data suggest the independence of autonomic and cognitive responding in the single-cue Pavlovian paradigm.     

The effect of similarities in skin texture and hand shape on perceived ownership of a fake limb

In the rubber-hand illusion (RHI), people attribute an artificial object to their own body. In the present study, we investigate the extent to which RHI is affected by visual discrepancies between the artificial object and a human hand. We tested Armel and Ramachandran's (2003) hypothesis that people will experience a stronger RHI when the artificial object is a skin-like textured sheet instead of a tabletop. We did not find support for their hypothesis, but the strength of the RHI diminished when the texture of a hand-shaped object did not resemble the human skin (manipulated by putting a white glove over the cosmetic prosthesis). We provide an alternative explanation for this finding, based on a skill-based sensorimotor account of perceived body ownership. Such an explanation supports Armel and Ramachandran's more general claim that discrepancies in the nature of expected and felt touch diminish the RHI.     

Recently inhibited responses are avoided for both masked and nonmasked primes in a spatial negative priming task

Responding to the location of a target is delayed when the target arises at a position previously occupied by a distractor (ignored-repetition trial), relative to when it occurs at a formerly unoccupied location (control trial) [i.e., the spatial negative priming (SNP) effect]. Speculation has held that recently inhibited (distractor) responses resist future execution (i.e., execution resistance [ER]), and thus cause SNP. Evidence for ER has been reported for identity-based tasks using masked prime distractor events. The purpose of this study was to examine the potential impact of ER on response selection in an SNP task for both nonmasked (traditional) and masked primes. We employed a modified SNP task that included nonmasked and masked target-only and distractor-only visual primes (first trial), along with forced choice and free choice probes (second trial). On free choice trials, a selection bias against the prime-distractor-assigned response was evident (same-hand competition, for both nonmasked and masked primes). This selection avoidance was held to reflect ER operating with inhibited prime distractor responses. Further, inhibitory aftereffect patterns were the same for nonmasked and masked distractor primes, and masking target primes transformed a positive to a negative aftereffect, as predicted by the self-inhibition model of mask function set out by Schlaghecken and Eimer (Psychonomic Bulletin & Review, 11, 463-468, 2004).     

Figure-ground organization in real and subjective contours: a new ambiguous figure, some novel measures of ambiguity, and apparent distance across regions of figure and ground

This study was designed to assess the effects of organization, luminance contrast, sector angle, and orientation on a new, highly ambiguous Cs-keyhole figure. Organization and contrast were the most important factors, and sector angle also influenced figure-ground relationships. There was no significant effect of orientation, nor was there any significant interaction between any of the factors. Several new measures of figure-ground organization were developed, such as ambiguity ratios based on reaction times and on ratings of the strength of perceived organizations, providing new quantitative measures of figure-ground relationships. Distances measured across figural regions appeared smaller than equal distances across the ground in the new reversible figure, and also in Rubin's classic vase-face figure presented in real and subjective contours. Inducing a perceptual set to see a particular organization in a reversible figure influenced the apparent distance across that organization. Several possible explanations of the observed effects are considered: (1) an instance of Emmert's law, based on the difference in apparent depth of figure and ground; (2) an aspect of the Müller-Lyer illusion; (3) a feature-detector model of contour attraction; (4) a natural set or predisposition to see a figure as smaller; and (5) framing effects. The first two explanations appear the most promising.     

Object correspondence across brief occlusion is established on the basis of both spatiotemporal and surface feature cues

The correspondence problem is a classic issue in vision and cognition. Frequent perceptual disruptions, such as saccades and brief occlusion, create gaps in perceptual input. How does the visual system establish correspondence between objects visible before and after the disruption? Current theories hold that object correspondence is established solely on the basis of an object’s spatiotemporal properties and that an object’s surface feature properties (such as color or shape) are not consulted in correspondence operations. In five experiments, we tested the relative contributions of spatiotemporal and surface feature properties to establishing object correspondence across brief occlusion. Correspondence operations were strongly influenced both by the consistency of an object’s spatiotemporal properties across occlusion and by the consistency of an object’s surface feature properties across occlusion. These data argue against the claim that spatiotemporal cues dominate the computation of object correspondence. Instead, the visual system consults multiple sources of relevant information to establish continuity across perceptual disruption.     

The effect of asymmetrical association on positive and negative semantic priming

One's actively ignoring a stimulus can impair subsequent responding to that stimulus. This negative priming effect has been argued to generalize to semantically related items as well, but the evidence for this is still somewhat weak. This article presents a new experiment in which participants made lexical decisions to asymmetrically associated prime-target pairs presented in either the forward (e.g., stork-baby) or backward (e.g., baby-stork) direction. The critical new finding was that both attended positive and ignored negative semantic priming occurred only for prime-target pairs presented in the forward direction. The results support either (1) a spreading inhibition model in which items associated with an ignored distractor are inhibited during prime selection or (2) a version of episodic retrieval theory in which the prime distractor and items associated with it are tagged as "to-be-ignored" during prime selection.     

The effect of cognitive load and hyperarousal on negative intrusive memories

Clinical theories of post-traumatic stress suggest that encoding processes at the time of a trauma are critical in determining whether intrusive memories will develop. Potential mechanisms that might influence the development of intrusive memories were studied, as was objective memory performance. In an analogue design, 65 participants were randomised to three conditions (cognitive load, hyperventilation, and control), and then watched a film of traumatic content. Intrusive memories were recorded during the experimental phase and at 1-week follow-up. Support was found for the prediction that verbal cognitive load and hyperventilation would facilitate intrusion development immediately following exposure to the trauma film; however, this was not maintained at follow-up. Consistent with cognitive models of post-traumatic stress, thought suppression and the distress associated with intrusive experiences mediated the relationship between distress caused by the film and intrusions at 1-week follow-up. Objective memory testing indicated that the three experimental groups showed similar recall and recognition performance for the content of the film; however, relative to the control group, individuals in the cognitive load condition were significantly less able to place film scenes in the correct order.