Differences In Visual Processing Research Articles

Sex Differences in Adults’ Relative Visual Interest in Female and Male Faces, Toys, and Play Styles

An individual's reproductive potential appears to influence response to attractive faces of the opposite sex. Otherwise, relatively little is known about the characteristics of the adult observer that may influence his or her affective evaluation of male and female faces. An untested hypothesis (based on the proposed role of attractive faces in mate selection) is that most women would show greater interest in male faces whereas most men would show greater interest in female faces. Further, evidence from individuals with preferences for same-sex sexual partners suggests that response to attractive male and female faces may be influenced by gender-linked play preferences. To test these hypotheses, visual attention directed to sex-linked stimuli (faces, toys, play styles) was measured in 39 men and 44 women using eye tracking technology. Consistent with our predictions, men directed greater visual attention to all male-typical stimuli and visual attention to male and female faces was associated with visual attention to gender conforming or nonconforming stimuli in a manner consistent with previous research on sexual orientation. In contrast, women showed a visual preference for female-typical toys, but no visual preference for male faces or female-typical play styles. These findings indicate that sex differences in visual processing extend beyond stimuli associated with adult sexual behavior. We speculate that sex differences in visual processing are a component of the expression of gender phenotypes across the lifespan that may reflect sex differences in the motivational properties of gender-linked stimuli.

DEFICITS IN PREFRONTAL AND SENSORY INTERACTIONS IN TOP-DOWN CONTROL IN SCHIZOPHRENIA

When two brief flashes presented in rapid succession (< 100 ms apart) are paired with a single auditory stimulus, subjects often report perceiving only a single flash [Andersen, T.S., Tiippana, K., Sams, M., 2004. Factors influencing audiovisual fission and fusion illusions. Brain Res. Cogn. Brain Res. 21, 301–308; Shams, L., Iwaki, S., Chawla, A., Bhattacharya, J., 2005a. Early modulation of visual cortex by sound: an MEG study. Neurosci. Lett. 378, 76–81, Shams, L., Ma, W.J., Beierholm, U., 2005b. Sound-induced flash illusion as an optimal percept. Neuroreport 16, 1923–1927]. We used event-related potentials (ERPs) to investigate the timing and localization of the cortical processes that underlie this sound induced flash fusion, which is complementary to the sound-induced extra flash illusion that we analyzed previously [Mishra, J., Martinez, A., Sejnowski, T.J. and Hillyard, S.A., Early cross-modal interactions in auditory and visual cortex underlie a sound-induced visual illusion. J. Neurosci. 27 (2007) 4120–4131]. The difference ERP that represented the cross-modal interaction between the visual (two flashes) and auditory (one sound) constituents of the bimodal stimulus revealed a positive component elicited 160–190 ms after stimulus onset, which was markedly attenuated in subjects who did not perceive the second flash. This component, previously designated as PD180 [Mishra, J., Martinez, A., Sejnowski, T.J. and Hillyard, S.A., Early cross-modal interactions in auditory and visual cortex underlie a sound-induced visual illusion. J. Neurosci. 27 (2007) 4120–4131], was localized by dipole modeling to polysensory superior temporal cortex. PD180 was found to covary in amplitude across subjects with the visual evoked N1 component (148–184 ms), suggesting that inter-individual differences in perceiving the illusion are based at least in part on differences in visual processing. A trial-by-trial analysis found that the PD180 as well as a subsequent modulation in visual cortex at 228–248 ms was diminished on trials when the two flashes were perceived as one relative to trials when two flashes were correctly reported. These results suggest that the sound induced flash fusion is based on an interaction between polysensory and visual cortical areas.

Cortical processes underlying sound-induced flash fusion

When two brief flashes presented in rapid succession (< 100 ms apart) are paired with a single auditory stimulus, subjects often report perceiving only a single flash [Andersen, T.S., Tiippana, K., Sams, M., 2004. Factors influencing audiovisual fission and fusion illusions. Brain Res. Cogn. Brain Res. 21, 301–308; Shams, L., Iwaki, S., Chawla, A., Bhattacharya, J., 2005a. Early modulation of visual cortex by sound: an MEG study. Neurosci. Lett. 378, 76–81, Shams, L., Ma, W.J., Beierholm, U., 2005b. Sound-induced flash illusion as an optimal percept. Neuroreport 16, 1923–1927]. We used event-related potentials (ERPs) to investigate the timing and localization of the cortical processes that underlie this sound induced flash fusion, which is complementary to the sound-induced extra flash illusion that we analyzed previously [Mishra, J., Martinez, A., Sejnowski, T.J. and Hillyard, S.A., Early cross-modal interactions in auditory and visual cortex underlie a sound-induced visual illusion. J. Neurosci. 27 (2007) 4120–4131]. The difference ERP that represented the cross-modal interaction between the visual (two flashes) and auditory (one sound) constituents of the bimodal stimulus revealed a positive component elicited 160–190 ms after stimulus onset, which was markedly attenuated in subjects who did not perceive the second flash. This component, previously designated as PD180 [Mishra, J., Martinez, A., Sejnowski, T.J. and Hillyard, S.A., Early cross-modal interactions in auditory and visual cortex underlie a sound-induced visual illusion. J. Neurosci. 27 (2007) 4120–4131], was localized by dipole modeling to polysensory superior temporal cortex. PD180 was found to covary in amplitude across subjects with the visual evoked N1 component (148–184 ms), suggesting that inter-individual differences in perceiving the illusion are based at least in part on differences in visual processing. A trial-by-trial analysis found that the PD180 as well as a subsequent modulation in visual cortex at 228–248 ms was diminished on trials when the two flashes were perceived as one relative to trials when two flashes were correctly reported. These results suggest that the sound induced flash fusion is based on an interaction between polysensory and visual cortical areas.

Visual Information Processing of Faces in Body Dysmorphic Disorder

Body dysmorphic disorder (BDD) is a severe psychiatric condition in which individuals are preoccupied with perceived appearance defects. Clinical observation suggests that patients with BDD focus on details of their appearance at the expense of configural elements. This study examines abnormalities in visual information processing in BDD that may underlie clinical symptoms. To determine whether patients with BDD have abnormal patterns of brain activation when visually processing others' faces with high, low, or normal spatial frequency information. Case-control study. University hospital. Twelve right-handed, medication-free subjects with BDD and 13 control subjects matched by age, sex, and educational achievement. Intervention Functional magnetic resonance imaging while performing matching tasks of face stimuli. Stimuli were neutral-expression photographs of others' faces that were unaltered, altered to include only high spatial frequency visual information, or altered to include only low spatial frequency visual information. Blood oxygen level-dependent functional magnetic resonance imaging signal changes in the BDD and control groups during tasks with each stimulus type. Subjects with BDD showed greater left hemisphere activity relative to controls, particularly in lateral prefrontal cortex and lateral temporal lobe regions for all face tasks (and dorsal anterior cingulate activity for the low spatial frequency task). Controls recruited left-sided prefrontal and dorsal anterior cingulate activity only for the high spatial frequency task. Subjects with BDD demonstrate fundamental differences from controls in visually processing others' faces. The predominance of left-sided activity for low spatial frequency and normal faces suggests detail encoding and analysis rather than holistic processing, a pattern evident in controls only for high spatial frequency faces. These abnormalities may be associated with apparent perceptual distortions in patients with BDD. The fact that these findings occurred while subjects viewed others' faces suggests differences in visual processing beyond distortions of their own appearance.

Testing Predictions from the Hunter-Gatherer Hypothesis — 2: Sex Differences in the Visual Processing of near and Far Space

Here, in the second of two linked reports, we focus on sex differences in visual processing. Study 1 presented a time estimation task in virtual space and generated the predicted Space*Sex interaction with men performing significantly better in far than in near space. Study 2 used a laboratory-based puzzle completion task in which participants saw their hands and the puzzle in far or near space. This time women performed significantly better in near than far space. Study 3 simplified the puzzle completion task. Once again the predicted Space*Sex interaction was significant but with both sexes showing significantly different performances: women better in near, men in far space. These findings are compatible with an evolutionary origin as predicted by the hunter-gatherer hypothesis. Far and near space are processed in the ventral and dorsal streams, two cortical regions more widely known as the “what” and “where” visual systems. To those traditional descriptions we suggest adding that the two streams are sex-dimorphic, with the ventral “there” system interacting with far space and favored in men and the dorsal “here” system interacting with near space and favored in women. Future studies of visual systems should consider the impact of sex differences and the spatial location of stimulus presentations.

Reading in two writing systems: Accommodation and assimilation of the brain's reading network

Bilingual reading can require more than knowing two languages. Learners must acquire also the writing conventions of their second language, which can differ in its deep mapping principles (writing system) and its visual configurations (script). We review ERP (event-related potential) and fMRI studies of both Chinese–English bilingualism and Chinese second language learning that bear on the system accommodation hypothesis: the neural networks acquired for one system must be modified to accommodate the demands of a new system. ERP bilingual studies demonstrate temporal indicators of the brain's experience with L1 and L2 and with the frequency of encounters of words in L2. ERP learning studies show that early visual processing differences between L1 and L2 diminish during a second term of study. fMRI studies of learning converge in finding that learners recruit bilateral occipital-temporal and also middle frontal areas when reading Chinese, similar to the pattern of native speakers and different from alphabetic reading. The evidence suggests an asymmetry: alphabetic readers have a neural network that accommodates the demands of Chinese by recruiting neural structures less needed for alphabetic reading. Chinese readers have a neural network that partly assimilates English into the Chinese system, especially in the visual stages of word identification.

Aging and Capacity in the Same-Different Judgment

ABSTRACT The same-different judgment was used in two experiments to investigate age-group differences in visual processing. Two targets next to fixation were presented; the targets on one-half of the trials were the same, and on the other half of the trials, the targets differed by color, shape, or color and shape (redundant). Response times were lower for redundant trials than for color-only and shape-only trials; this redundancy gain was greater for older observers than for young observers. Capacity measures based on the integrated hazard functions indicated that young adults, but not older adults, experienced a slowing of processing (reduction of capacity) in the redundant condition. These capacity measures may provide a method for interpreting age-group effects in the presence of overall response-time differences.

Preservation of Episodic Visual Recognition Memory in Aging

Visual episodic recognition memory was assessed in young (mean age 22.5 years) and older (mean age 74.1 years) adults. To isolate purely visual memory, recognition was tested with sets of briefly-presented compound sinusoidal gratings, which minimized age-related differences in visual processing, and resisted verbal encoding. Recognition was measured after delays of 1, 2 or 4 seconds. Overall, neither accuracy of recognition nor speed of response differed significantly between groups, or with probe delay, which strengthens recent claims that visual memory tends to be spared during the course of normal aging.

Hemispheric Processes in the Perception of Art

Known differences in visual processing between the cerebral hemispheres imply the possibility of lateral asymmetry in aesthetic evaluation of art. In a test of this proposition, 40 participants were asked to indicate their preference for paintings projected to the left or right visual field. The stimuli were selected from representative works drawn from eight different European schools of art ranging from the 15th to 20th centuries. An overall right visual field preference was found for the paintings. A principal components analysis revealed that participants evaluated the paintings in terms of two distinct groups: older realistic art and more recent abstract art. The right visual field preference was found to apply only to abstract art. This finding is interpreted in terms of selective activation of each side of the brain resulting in the generation of asymmetrical affective states which influence aesthetic judgments.

Monocular Vision Leads to a Dissociation between Grip Force and Grip Aperture Scaling during Reach-to-Grasp Movements

It has been argued that visual perception and the visual control of action depend upon functionally distinct and anatomically separable brain systems [1–3]. Electrophysiological [4] evidence indicates that binocular vision may be particularly important for the visuomotor processing within the posterior parietal cortex, and neuropsychological [5, 6] and psychophysical [7–11] studies confirm that binocular vision is crucial for the accurate planning and control of prehension movements. An unresolved issue concerns the consequences for visuomotor processing of removing binocular vision. By one account, monocular viewing leads to reliance upon pictorial visual cues to calibrate grasping [6] and results in disruption to normal size-constancy mechanisms [6, 7]. This proposal is based on the finding that maximum grip apertures are reduced with monocular vision. By a second account, monocular viewing results in the loss of binocular visual cues and leads to strategic changes in visuomotor processing by way of altered safety margins [9–11]. This proposal is based on the finding that maximum grip apertures are increased with monocular vision. We measured both grip aperture and grip force during prehension movements executed with binocular and monocular viewing. We demonstrate that each of the above accounts may be correct and can be observed within the same task. Specifically, we show that, while grip apertures increase with monocular vision, consistent with altered visuomotor safety margins, maximum grip force is nevertheless reduced, consistent with a misperception of object size. These results are related to differences in visual processing required for calibrating grip aperture and grip force during reaching.

Differences in visual processing in dyslexia revealed with functional magnetic resonance imaging

Differences in visual processing in dyslexia revealed with functional magnetic resonance imaging

Seeing gray through the ON and OFF pathways.

Color appearance judgments revealed fundamental differences in visual processing of incremental and decremental lights. First, the balance of cone activation required for a light to appear achromatic was different for increments and decrements (Judd, 1940; Helson & Michels, 1948). Second, adaptation--the visual system's adjustment to background light--affected achromatic decrements more than increments. Third, the regulation of adaptation for incremental and decremental stimuli depended differently on background signals from the three cone types. We interpret these asymmetries as differences in mechanisms of adaptation in the ON and OFF pathways, and suggest that they evolved to accommodate the range and physical sources of color signals in the two pathways.

Developmental differences in visual processing: Strategy versus structure

The present study was an examination of two contrasting explanations for the finding that young children tend to classify objects according to similarity relations whereas adults emphasize dimensional structure. Subjects from three different age groups were given tasks that tapped different aspects of the visual process: Feature search, Conjunction search, and Restricted Classification tasks. In addition, three different stimulus objects (a highly separable, a highly integral, and an intermediate dimensional combination) were studied to explore the contribution of stimulus structure in dictating the nature of the processing mode. The results provided evidence against the view that children perceive objects according to a more primitive holistic structure. Rather, the results can be taken with past research to suggest that less efficient visual processing may lead the younger subjects to adopt a classification strategy that emphasizes similarity relations. In addition, the current research supported Garner's (1974, The processing of information and structure, Potomac, MD: Erlbaum) suggestion that the nature of the processing mode is stimulus-driven.

Binocular Advantage and Visual Processing in Dyslexic and Control Children as Measured by Visual Evoked Potentials

The role of visual processing in dyslexia continues to stir controversy. Previous research using early components of visual evoked potentials (VEP's) has revealed differences in visual processing between dyslexics and controls. VEP's have successfully indexed binocular advantage. Intrasensory functioning could conceivably be deficient in dyslexics. This study recorded VEP's in response to contrast-reversing checkerboards binocularly and monocularly from dyslexic and control children. The overall monocular and binocular amplitudes of the major positive peaks (P100) were greater for controls than dyslexics; however, contrary to the original hypothesis, the magnitude of binocular advantage was higher for dyslexics than for the control children. Stimulus factors had an effect, but did not interact with reading ability.

Developmental versus sensory deficit effects on perceptual processing in the reading disabled.

Thirty children and 5 adults participated in two experiments designed to compare visual processing in normal and reading disabled children. The children were aged 8, 10, and 12 years. In Experiment 1, subjects were asked to detect the temporal order of two briefly presented stimuli. In Experiment 2, subjects sorted cards containing bracket stimuli that did or did not produce perceptual grouping effects. Poor readers required more time to make accurate temporal order judgments and showed stronger perceptual grouping effects. For both good and poor readers, the amount of time necessary to make a correct temporal order judgment decreased, and perceptual grouping effects became weaker with age. However, the magnitude of the difference between the groups did not lessen with age. These results suggest that there are visual processing differences between good and poor readers that do not appear to correct by age 12.

RELATIVE VS ABSOLUTE RIGHT HEMISPHERE SUPERIORITY FROM LATERAL DIFFERENCES IN VISUAL PROCESSING BY NORMALS: AN EXAMPLE OF UNCERTAINTY IN EXPERIMENTAL NEUROPSYCHOLOGY

Statistical tools (correlations and analyses of variance) have been proposed to decide whether a hemispheric functional asymmetry reflects absolute or relative cerebral superiority. A set of 16 normal subjects were given two tasks involving right hemisphere competences in the visual modality: the recognition of a small set of easily discriminated faces and meaningless geometrical figures, displayed in the lateral visual fields. The statistical tools did not perfectly agree with one another as had already been noted in a previous study. The results also showed a left hemisphere advantage, contrary to expectations; this last observation is linked with a possible asymmetrical effect of familiarization with the material

Projections to the superior temporal sulcus from the central and peripheral field representations of V1 and V2.

In a series of three studies, we have begun to explore the sequence of visual information processing along the pathway from striate cortex (V1), through MT, into the parietal lobe. In this first study, we sought to establish the relationships among MT, the heavily myelinated zone of the superior temporal sulcus (STS), and the V1 and V2 projection fields in the STS. Autoradiographic material from seven hemispheres of six macaques injected with tritiated amino acids into either V1 or V2 was analyzed in detail, and the results were plotted onto two-dimensional reconstructions of the STS. Autoradiographic material from eight additional macaques with V2 injections was also examined. The results indicate that the central visual field representations of both V1 and V2 project into the heavily myelinated zone in the lower bank and floor of the STS, confirming prior studies, whereas the far peripheral representations of both V1 and V2 project into the cortex medial to this zone on the upper bank of the sulcus. There is no evidence that this medial cortex is a separate area that receives projections from V1 and V2 in parallel with the projections these areas send to the heavily myelinated zone. Rather, there seems to be a single projection field of V1 and V2 whose central representation lies within the heavily myelinated zone and whose most peripheral representation lies medial to it. Because of the difference in myelination between the central and peripheral field representations as well as visuotopic anomalies between them, we retain the term "MT" for the heavily myelinated zone and apply the term "MTp" to the far peripheral projection zone. Both MT and MTp are required to process the complete outputs of V1 and V2 within the STS and thus should probably be regarded as two distinctive parts of a single visual area. The difference in myelination between MT and MTp suggests that there is a difference in visual processing between the central and peripheral visual fields. The average size of MT is estimated to be 62 mm2, and the average size of MT and MTp combined to be 76 mm2, which is consistent with estimates derived from several other studies.

Effects of Symbol Structure on Visual Information Processing

This investigation addresses the problem of attention in the processing of symbolic information from visual displays. Its scope includes the nature of attentive processes, the structural properties of stimuli that influence visual information processing mechanisms, and the manner in which these factors interact in perception. Our purpose is to determine the effects of configural feature structure on visual information processing. It is known that for stimuli comprising separable features, one can distinguish between conditions in which only one relevant feature differs among stimuli in the array being searched and conditions in which conjunctions of two (or more) features differ: Since the visual process of conjoining separable features is additive, this fact is reflected in search time as a function of array size, with feature conditions yielding flat curves associated with parallel search (no increase in search time across array sizes) and conjunction conditions yielding linearly increasing curves associated with serial search. We studied configural-feature stimuli within this framework to determine the nature of visual processing for such stimuli as a function of their feature structure. Response times of subjects searching for particular targets among structured arrays of distractors were measured in a speeded visual search task. Two different sets of stimulus materials were studied in array sizes of up to 32 stimuli, using both tachistoscope and microcomputer-based CRT presentation for each. Our results with configural stimuli indicate serial search in all of the conditions, with the slope of the response-time-by-array-size function being steeper for conjunction conditions than for feature conditions. However, for each of the two sets of stimuli we studied, there was one configuration that stood apart from the others in its set in that it yielded significantly faster response times, and in that conjunction conditions involving these particular stimuli tended to cluster with the feature conditions rather than with the other conjunction conditions. In addition to these major effects of particular targets, context effects also appeared in our results as effects of the various distractor sets used; certain of these context effects appear to be reversible. The effects of distractor sets on target search were studied in considerable detail. We have found interesting differences in visual processing between stimuli comprising separable features and those comprising configural features. We have also been able to characterize the effects we have found with configural-feature stimuli as being related to the specific feature structure of the target stimulus in the context of the specific feature structure of distractor stimuli. These findings have strong implications for the design of symbology that can enhance visual performance in the use of automated displays.

Individual differences in the cognitive processes of reading: I. Word decoding.

The importance of word decoding in accounting for individual differences in reading comprehension is discussed. Research on individual differences in the cognitive processes that mediate word decoding is reviewed. It is concluded that a large proportion of the variance in word decoding ability is accounted for by phonological processes, and that little variance is explained by differences in visual processes. Possible causal relationships and developmental changes also are discussed.