An effect of mood on the perception of geographical slant

Previous research has shown that hills appear steeper to those who are fatigued, encumbered, of low physical fitness, elderly, or in declining health (Bhalla & Proffitt, 1999; Proffitt, Bhalla, Gossweiler, & Midgett, 1995). The prevailing interpretation of this research is that observers’ perceptions of the environment are influenced by their capacity to navigate that environment. The current studies extend this programme by investigating more subtle embodied effects on perception of slant; namely those of mood. In two studies, with two different mood manipulations, and two estimates of slant in each, observers in a sad mood reported hills to be steeper. These results support the role of mood and motivational factors in influencing spatial perception, adding to the previous work showing that energetic potential can influence perception.     

An effect of mood on the perception of geographical slant

Previous research has shown that hills appear steeper to those who are fatigued, encumbered, of low physical fitness, elderly, or in declining health (Bhalla & Proffitt, 1999; Proffitt, Bhalla, Gossweiler, & Midgett, 1995). The prevailing interpretation of this research is that observers' perceptions of the environment are influenced by their capacity to navigate that environment. The current studies extend this programme by investigating more subtle embodied effects on perception of slant; namely those of mood. In two studies, with two different mood manipulations, and two estimates of slant in each, observers in a sad mood reported hills to be steeper. These results support the role of mood and motivational factors in influencing spatial perception, adding to the previous work showing that energetic potential can influence perception.     

A computer-graphic technique for the study of body size perception and body types

We present a novel approach for measuring body size estimation in normal and eating-disordered women and men. Clinical categories of body types were used as prototypes. By comparing the subjective appearance of a person’s body with prototypes, we can understand how different attributes of his or her body shape contribute to perception of body size. After lifelike random distortions have been applied to parts of their body image, individuals adjust their body shapes until they converge on their perceived veridical appearance. Exaggeration and minimization of particular body areas measured with respect to their true shape and with different prototypes can be expressed as numerical deviations. In this way, perceived body size and body attractiveness can be appraised during the course of diagnosis and treatment of eating disorders.     

Wanting a body that's better than average: the effect of manipulated body norms on ideal body size perception

We examined the effect of body norms on ideal and current body size perception. In Study One, female participants were randomly assigned to one of three experimental conditions: (1) a thinner body norm, (2) a heavier body norm, or (3) no body norm. Body norms were manipulated by indicating a bogus "population average," and current and ideal body size perception were subsequently measured using a body silhouettes measure. Women had a thinner ideal body size in the thinner norm condition than in the heavier norm condition. Study Two replicated these results, but in a sample of young men and with regards to muscularity rather than thinness. Men had a more muscular ideal body size in the more muscular norm condition than in the less muscular norm condition. Current body size perception was also influenced by body norms, but only for women and after controlling for BMI.     

Seeing the body distorts tactile size perception

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40 mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception.     

Qualitative influences on the perception of movement: An experimental study

One of the most puzzling features of “hyperactivity” in children is the importance of activity itself. Generalized overactivity has not been found to be a valid diagnostic marker. Could some qualitative features of activity be important determinants of the perceived quantity of activity? The analogue study reported here derives from a social-psychological hypothesis that anything that makes a behavior more noticeable or distracting can create an illusion of increased movement. Subjects performed a simple cognitive task while watching short films of adult actors. Two variables were manipulated: (a) The sound level was either loud or quiet, and (b) instructions to subjects were varied so that the behaviors shown were perceived as either appropriate or inappropriate. Results strongly supported the hypothesis. Loudness and contextual inappropriateness made the films more distracting, produced higher ratings of the amount of movement observed, and led to more negative evaluations of the behaviors seen. Implications for assessment and intervention are discussed.     

Effects of mood and knowledge on evaluations: An experimental study

An experimental study was conducted to estimate the impact of subjects' mood states on their responses to evaluative ratings. Four experimental groups were induced by either a very negative, mildly negative, neutral or positive mood-inducing film. As hypothesized, systematic differences were found between the groups in their evaluations. Factual knowledge about the evaluation object was, contrary to expected, not found to modify mood effects. This negative finding could, however, be explained by a strong stereotypical impression of the object (a distant travel destination) held by the respondents.     

An exploration of perception of body boundary, personal space, and body size in elderly persons.

A study of 108 elderly persons using the Body Distortion Questionnaire and the personal space simulation technique test did not support hypotheses that elderly persons with a large personal space will have a larger distortion of body boundary, a larger perception of large body size, a smaller perception of small body size, a larger distortion of body size, and a larger body distortion than elderly persons with a small personal space. The analyses with one-tail t tests showed elderly persons with a small personal space have a larger perception of large body size and a larger distortion of body size than elderly persons with a large personal space. When the extremes of personal space were used the results were the same. Males have a larger personal space and greater distortion of skin perceptions than females.     

An experimental synthesis of the associations and gestalt accounts of the perception of size. part iii

Two control experiments are described which are concerned with the effect, on judgements of size, of varying the angular separation of the compared objects in the horizontal plane. The first experiment investigates order effects. The second experiment compares judgements of real size at small and large angles of separation. The findings are discussed in relation to parts I and II of these papers.     

Visual distortion of body size modulates pain perception

Pain is a complex subjective experience that is shaped by numerous contextual factors. For example, simply viewing the body reduces the reported intensity of acute physical pain. In this study, we investigated whether this visually induced analgesia is modulated by the visual size of the stimulated body part. We measured contact heat-pain thresholds while participants viewed either their own hand or a neutral object in three size conditions: reduced, actual size, or enlarged. Vision of the body was analgesic, increasing heat-pain thresholds by an average of 3.2 °C. We further found that visual enlargement of the viewed hand enhanced analgesia, whereas visual reduction of the hand decreased analgesia. These results demonstrate that pain perception depends on multisensory representations of the body and that visual distortions of body size modulate sensory components of pain.     

An experimental synthesis of the associations and gestalt accounts of the perception of size: Part I

The Associationists state that our everyday impressions of size are a product of past experience. The Gestalt psychologists state that they are immediately or directly given in present experience. The experiment described here suggests that both past and present experience are simultaneously involved, and that a synthesis of the two accounts is required.     

An experimental synthesis of the associations and gestalt accounts of the perception of size: Part II

A quantitative and qualitative analysis is given of the judgements described in Part I of this paper. The relation between the findings of the experiment, and the Associationist and Gestalt accounts, is discussed.     

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.     

The effects of ambiguous appearance-related feedback on body image,mood states,and intentions to use body change strategies in college women: An experimental study

The current study evaluated the effects of receiving ambiguous appearance-based or nonappearance-based feedback on body image, mood states, and body change strategies. One hundred and forty-six women were randomly assigned to either an appearance condition, wherein they interacted with a confederate supposedly working for a cosmetic surgery center, or a nonappearance condition, in which the confederate purportedly worked for an academic enhancement center. Counter to expectations, there was no evidence of significant group differences on most of the variables that assessed mood states and body change strategies. However, intentions to engage in bulimic behavior were significant higher and dieting intentions marginally higher at posttest for the appearance condition, however anger levels were significantly higher for the nonappearance condition. Limitations of the study are discussed and future indications for research in this area are suggested.     

Weber's illusion and body shape: anisotropy of tactile size perception on the hand

The perceived distance between touches on a single skin surface is larger on regions of high tactile sensitivity than those with lower acuity, an effect known as Weber's illusion. This illusion suggests that tactile size perception involves a representation of the perceived size of body parts preserving characteristics of the somatosensory homunculus. Here, we investigated how body shape is coded within this representation by comparing tactile distances presented in different orientations on the hand. Participants judged which of two tactile distances on the dorsum of their left hand felt larger. One distance was aligned with the proximodistal axis (along the hand), the other with the mediolateral axis (across the hand). Across distances were consistently perceived as larger than along ones. A second experiment showed that this effect is specific to the hairy skin of the hand dorsum and does not occur on glabrous skin of the palm. A third experiment demonstrated that this bias reflects orientation on the hand surface, rather than an eye- or torso-centered reference frame. These results mirror known orientational anisotropies of both tactile acuity and of tactile receptive fields (RFs) of cortical neurons. We suggest that the dorsum of the hand is implicitly represented as wider than it actually is and that the shape of tactile RFs may partly explain distortions of mental body representations.     

The effect of marker size on the perception of an empty interval

Research shows that the time that is spent perceiving a brief visual stimulus is experienced as increasing as the size of the stimulus increases. We examined whether the experienced duration of time that is spent attending the perception of an empty interval—demarcated by the offset of one marker and the onset of a second marker— depends on the size of the markers themselves. Previous theories predict that the perceived time that is spent viewing offset-to-onset intervals decreases as the size of the markers increases, and that the perceived time that is spent viewing the markers increases. We demonstrated that empty intervals between the presentations of large markers were perceived to be longer in duration than those occurring between the presentations of small markers, and that the second marker was critical to this effect of physical size on apparent duration. We report that the size effect disappeared when the interval was filled with the presentation of a circle, and we conclude that the intensity of the second marker altered perceptions in an empty-interval-specific manner.     

The effect of object familiarity on the perception of size and distance

The perceived sizes and perceived distances of familiar objects were investigated in two experiments in which images of familiar objects were presented monocularly, one at a time, in an otherwise dark field of view. It was found that the angular size of the objects as well as their familiar size determined reported size. Reported distances were increasingly underestimated as a function of increasing simulated distances of the objects. The results are consistent with the conclusion that, as a function of the retinal size of the objects, the observer perceives the familiar objects as off-sized, and, that as a consequence of these off-sized perceptions, the observer's judgements of the object distances reflect inferential rather than perceptual processes.