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PubMed2005

Do child molesters deliberately fake good on cognitive distortion questionnaires? An information processing-based investigation.

Researchers and clinicians hypothesize that child molesters hold offence-supportive beliefs or cognitive distortions that require restructuring for successful rehabilitation. However, there is little empirical evidence to support this hypothesis. Current questionnaire measures of both untreated and treated child molesters' cognitive distortions show that these men typically disagree with cognitive distortions. Such findings, especially prior to treatment, are often interpreted to mean that child molesters are faking good. In this study we drew on personality-related research showing that when participants intentionally respond in a socially desirable way on questionnaires, they make faster item responses than when answering honestly. Untreated child molesters, treated child molesters, and two types of controls (nonsexual offenders and nonoffenders) were administered a computerized cognitive distortion questionnaire and their responses and response times were recorded. Consistent with previous research, all groups tended to disagree with the cognitive distortions. However, response time data were surprising; only the treated child molesters displayed the fake-good pattern of responding significantly faster in rejecting cognitive distortions. We speculate about the implications of these results for the cognitive distortion hypothesis, and for understanding how current treatment programs effect cognitive distortion change.

Adult↗
PubMed1996

Emotions and cognitions associated with bingeing and weight control behavior in bulimia.

The examination of cognitions and emotions during the bulimic cycle is critical in understanding possible maintenance factors involved in bulimia. In this study, 22 bulimics and 22 nonbulimics recorded their thoughts and feelings every 2 waking hours over a 6-day period. Bulimics additionally recorded their moods and thoughts during their binges and compensatory behaviors (e.g., purging, exercise). Higher levels of negative affect were reported at all stages of the cycle compared to baseline, although negative affect decreased after the compensatory behavior stage. Subjects also reported stronger distorted cognitions before and after the binge compared to baseline. One of the distorted cognitions (feeling fat) decreased in strength after subjects engaged in compensatory behavior. Additional analyses revealed that most levels of negative affect and distorted cognitions were elevated prior to binges as compared to meals. Finally, negative affect and distorted cognitions were stronger after binges than after meals.

Adult↗
PubMed1994

Is the spatial deficit in strabismic amblyopia due to loss of cells or an uncalibrated disarray of cells?

We examine two competing explanations for the spatial localization deficit in human strabismic amblyopia, namely neural undersampling and uncalibrated neural disarray. An undersampling hypothesis would predict an associated deficit for contrast discrimination for which we find no evidence in strabismic amblyopia. A neural disarray hypothesis would predict an associated deficit in the degree to which stimuli appear spatially distorted. We find evidence for such a deficit in strabismic amblyopia. We propose that the spatial deficit in strabismic amblyopia is due to a filter-based distortion which is unable to be re-calibrated by higher visual centres.

Amblyopia↗
PubMed2003

Anxiety, threat perception abnormalities, and emotional reasoning in nonclinical Dutch children.

Examined the relation between childhood anxiety and threat-perception abnormalities using vignettes in which external (i.e., exposure to potential threat cues) and internal (i.e., experience of anxiety responses) information were systematically varied. Nonclinical children (N = 156) aged 8 to 13 years completed anxiety questionnaires and were then exposed to 3 types of stories: ambiguous stories, ambiguous + anxiety-response stories, and nonthreatening stories. From children's responses to these stories, a number of threat-perception indexes were derived. Results showed that both external and internal information inflated children's perception of threat. Further, high levels of anxiety were accompanied by enhanced threat perception in response to external threat cues. Finally, little evidence was found that high levels of anxiety, and in particular of anxiety sensitivity, were associated with a greater tendency to use internal information (i.e., emotional reasoning). Potential avenues for future studies on anxiety-related threat-perception distortions are briefly discussed.

Adolescent↗
PubMed1993

Serial spatial filters in vision.

Observers viewing two superimposed laser interference fringes of nearly equal spatial frequency see an illusory grating of low spatial frequency, even when the spatial frequency of the fringes exceeds the resolution limit. This grating is a product of nonlinear distortion within the visual system [MacLeod, Williams and Makous (1992) Vision Research, 32, 347-363]. By separately manipulating the spatial frequencies of the interference fringes and the distortion gratings, we decomposed the contrast sensitivity function into two serial components separated by the nonlinear process. Losses in the optics of the eye were avoided by use of laser interferometry. Spatial summation preceding the nonlinear stage was restricted to the light-collecting area of individual cones and was directly proportional to the diameters of cone inner segments at three retinal eccentricities; this suggests that light is trapped within cones at the level of their inner segments. Even 30 degrees from the fovea, the nonlinear stage precedes the site where separate signals from individual cones are no longer maintained; this leads us to suggest that the nonlinear process lies within the retina. In addition, spatial antagonism precedes the nonlinear stage; this places the nonlinear process at a site following the outer segments of the cones. Dichoptic presentation of the interference fringes failed to produce illusory gratings; that is, the nonlinearities within the binocular pathway do not produce distortions like those produced by the monocular nonlinearity.

Contrast Sensitivity↗
PubMed1993

Three syndrome concept of schizophrenia. A factor analytic study.

One hundred and fifty-five DSM-IIIR schizophrenic patients were assessed for positive and negative symptoms using Andreasen's Scale for Assessment of Positive Symptoms (SAPS) and the Scale for Assessment of Negative Symptoms (SANS). Interrelationships of individual positive and negative symptoms were examined using a factor analysis. Results of the factor analysis are consistent with Liddle's proposition that there are three syndromes underlying symptomatology in schizophrenia: disorganization; psychomotor poverty and reality distortion.

Adolescent↗
PubMed2006

Attention control in middle childhood: relations to psychopathological symptoms and threat perception distortions.

The present study examined the construct of attention control, which is an important aspect of effortful control, in a sample of non-clinical children aged between 9 and 13 years. Results demonstrated that attention control was associated with a broad range of psychopathological complaints, including symptoms of anxiety, aggression, depression, and ADHD. As predicted, lower levels of attention control were accompanied by higher levels of these symptoms. Further, attention control was also negatively related to threat perception distortions, which indicates that children who display low levels of this regulative temperament factor are more prone to such cognitive biases. Third, when controlling for neuroticism, attention control remained significantly (negatively) associated with symptoms of anxiety, depression (child report only), and ADHD. The correlations between attention control and threat perception distortions largely disappeared when the influence of neuroticism was partialled out. Only the link between attention control and anxious interpretations of ambiguous vignettes survived this correction. Finally, no evidence was found for the hypothesised mediating role of cognitive distortions on the relation between temperament factors and psychopathological symptoms.

Adolescent↗
PubMed1987

Obesity and body image: an evaluation of sensory and non-sensory components.

Body image in 38 obese and normal weight subjects was measured using a video TV monitor. Tasks included a continuous task where subjects manipulated the size of their body image on a TV screen, and a discrete task, where they judged the accuracy of their TV image which was presented as either too heavy or too thin. Subjects viewed their images in both regular street clothes and with minimal clothing. Results from the continuous task revealed that obese subjects overestimated body size. All subjects were more accurate on trials in which the initial image was adjusted in the heavier direction. On the discrete task, a signal detection analysis revealed sensory sensitivity differences between obese and normal weight subjects. Obese subjects were better at detecting distortion caused by a too thin image, but were inferior in detecting a too heavy distortion. No significant differences were obtained in response criteria or between clothing conditions.

Adult↗
PubMed1996

The role of sensory and nonsensory factors in body size estimations of eating disorder subjects.

Body size distortion of anorectic and bulimic subjects was compared to controls via a video-distortion technique. Subjects judged the whole body, chest, hips and stomach regions. A adaptive probit estimation (APE) methodology examined separately the sensory and nonsensory components of body image distortion. Eating disorder subjects overestimated body size more than control subjects. There were no significant differences between eating disorder groups, although there was more variability in eating disorder subjects. Subjects overestimated more on whole body as compared to body regions. There were no differences in sensory sensitivity to detecting size differences between groups. Results indicate that differences in body size distortion between eating disorder and control subjects are due exclusively to affective, nonsensory factors.

Adolescent↗
PubMed1992

Body size perception and body satisfaction in restrained and unrestrained eaters.

In 21 restrained and 20 unrestrained eaters body size perception was measured using the video distortion technique (VDT), the image marking procedure (IMP) and the kinesthetic size estimating apparatus (KSEA). Body satisfaction was assessed by questionnaires (Body Shape Questionnaire, Dieting scale of the Eating Attitudes Test). Restrained eaters showed no systematic over- or underestimation of the body size but less perceptual accuracy (in VDT and KSEA). Furthermore, they were clearly more dissatisfied with their bodies than unrestrained eaters. Both findings were unrelated to each other. In both groups depressive mood or thoughts seemed to be associated with body dissatisfaction but not with body size misperception. Objective body measures (body mass index, body fat content) were not related to either body size perception or body satisfaction. The findings suggest that a perceptual uncertainty in regard to body size (either for visual or for somatosensory aspects) has already developed in restrained eaters, which may constitute a predisposition for more overt forms of body size misperception as found in eating disorder patients.

Behavior Therapy↗
PubMed1990

Body image of sexually and physically abused children.

Body size perception was measured in 41 children aged 6-10 who had been either sexually or physically abused, or had no history of abuse. Two psychophysical methods were used, including the staircase method and a signal detection method. In the staircase methodology, children adjusted the direction of distortion of their continuously changing body size. In the signal detection method, children made judgments about the presence or absence of size distortion in presented images. Results using the staircase method indicated children overestimated their body sizes, with no differences between abuse conditions, gender, or age. For the signal detection methodology, no difference in ability to detect the presence/absence of size distortion (d') was found between abuse conditions, although females were less accurate than males. All groups were better able to detect distortion when the image was distorted too wide. Measures of response bias (Ln beta) indicated that sexually abused children had a greater bias to report size distortion as present, as compared with the physically abused children.

Body Image↗
PubMed2006

Prototype-distortion category learning: a two-phase learning process across a distributed network.

This paper reviews a body of work conducted in our laboratory that applies functional magnetic resonance imaging (fMRI) to better understand the biological response and change that occurs during prototype-distortion learning. We review results from two experiments (Little, Klein, Shobat, McClure, & Thulborn, 2004; Little & Thulborn, 2005) that provide support for increasing neuronal efficiency by way of a two-stage model that includes an initial period of recruitment of tissue across a distributed network that is followed by a period of increasing specialization with decreasing volume across the same network. Across the two studies, participants learned to classify patterns of random-dot distortions (Posner & Keele, 1968) into categories. At four points across this learning process subjects underwent examination by fMRI using a category-matching task. A large-scale network, altered across the protocol, was identified to include the frontal eye fields, both inferior and superior parietal lobules, and visual cortex. As behavioral performance increased, the volume of activation within these regions first increased and later in the protocol decreased. Based on our review of this work we propose that: (i) category learning is reflected as specialization of the same network initially implicated to complete the novel task, and (ii) this network encompasses regions not previously reported to be affected by prototype-distortion learning.

Adult↗
PubMed2002

Does representational momentum reflect a distortion of the length or the endpoint of a trajectory?

Observers viewed a moving target, and after the target vanished, indicated either the initial position or the final position of the target. In Experiment 1, an auditory tone cued observers to indicate either the initial position or the final position; in Experiment 2, different groups of observers indicated the initial position or the final position. Judgments of the initial position were displaced backward in the direction opposite to motion, and judgments of the final position were displaced forward in the direction of motion. The data suggest that the remembered trajectory is longer than the actual trajectory, and the displacement pattern is not consistent with the hypothesis that representational momentum results from a distortion of memory for the location of a trajectory.

Adult↗
PubMed2001

Photographic reproduction of out-of-focus and distorted ocular imagery.

The necessary settings and parameters were determined for ordinary camera and lens systems to faithfully reproduce out-of-focus and distorted imagery as it falls upon the retina of the human eye. Theoretic considerations of both geometric and physical optics were used to calculate the "relative blur" and distortion produced by refractive error added to ordinary camera lenses as opposed to refractive error in an arbitrary thick-lens optical system bounded by air and fluid (i.e. the eye). In both the camera and the eye, "relative blur" was determined to be directly proportional to dioptric defocus and to aperture size, and effectively independent of the focal length. Distortion of imagery was also found to be independent of the focal length. Photographs corroborate the theoretic findings. A given amount of relative blur, however, appeared somewhat greater when recorded on photographic film than when appreciated by the human eye. The Stiles-Crawford effect, the chromatic aberration of the eye, and neural processing probably each contribute to this difference. Previous investigators have grossly exaggerated blur and distortion in photographs intended to simulate ocular imagery and have drawn misleading conclusions from their results.

Humans↗
PubMed2003

Watching a cursor distorts haptically guided reproduction of mouse movement.

Participants moved a mouse along a force-feedback-defined linear path, either without vision or while watching a cursor set to 1 of 3 levels of visual:haptic gain (all >1:1). They attempted to haptically reproduce the movement without visual feedback. Errors increased with gain, reaching 70% overestimation at the highest gain. Forewarning participants about gain variability did not eliminate this effect. The gain level was potentially cued during the movement by the mismatch between visual feedback and kinesthetic feedback. Moreover, because participants did not achieve cursor-speed constancy across gain levels, visual speed was another cue to gain. Collectively, these cues failed to prevent visual distortion of movement reproduction.

Attention↗
PubMed1985

Spatial aberrations and acuity in strabismus and amblyopia.

Spatial uncertainty and distortion were quantified from judgement of the horizontal position of a flashed 0.5 deg vertical line with respect to a flanking reference target in strabismics with and without reduced acuity. Spatial uncertainty was outside the range of 30 normal eyes in all of 23 strabismic amblyopic eyes (visual acuity = 20/40 or worse) and in 20 of 22 squinting eyes with 20/30 or better acuity. Abnormal spatial distortion was found in 16 amblyopic and 10 squinting eyes. In the deviated eyes of the strabismics, the extent of spatial uncertainty and distortion correlated with visual acuity. Spatial aberrations were not accounted for by strabismics' unsteady or eccentric fixation, nor were they mimicked in normal eyes when visual acuity was artifically reduced. The authors suggest that spatial uncertainty and distortion represent the primary abnormalities in strabismics and produce deficits of visual acuity according to their severity.

Amblyopia↗
PubMed2006

Neuropsychological correlates of reality distortion in schizophrenic patients.

The present study aims at exploring the relationship between content-related aspects of delusions and hallucinations in schizophrenia and the basic domains of cognition, controlling for the other clinical and demographic variables that could produce bias in the interpretation of the results. Seventy stable schizophrenic patients were evaluated through psychiatric assessment and a neuropsychological battery including tests on attention, memory, perceptual-motor speed and executive functions. We found that the severity of negative symptoms was strongly correlated with poor performance in almost all domains of cognitive functions, while only the attentional deficit was correlated with positive symptoms. The relationships between different cognitive domains and specific types of delusions and hallucinations showed that thought insertion, guilt, grandiose, religious and somatic delusions were associated with impairment in different cognitive functions (verbal and visual memory, attention and executive functions). Voices arguing and tactile hallucinations were correlated to delay-recall memory function. Our results suggest that no specific cognitive pattern is associated with typical-content delusions and hallucinations. On the basis of our findings, cognitive impairments associated with delusions and hallucinations, as measured by our battery, seem not to play a central role in the genesis and the maintenance of these symptoms, suggesting a more complex model of pathogenesis.

Adult↗