Left Visual Field Superiority Research Articles

Neural correlates of the eye dominance effect in human face perception: the left-visual-field superiority for faces revisited.

Faces are processed best when they are presented in the left visual field (LVF), a phenomenon known as LVF superiority. Although one eye contributes more when perceiving faces, it is unclear how the dominant eye (DE), the eye we unconsciously use when performing a monocular task, affects face processing. Here, we examined the influence of the DE on the LVF superiority for faces using event-related potentials. Twenty left-eye-dominant (LDE group) and 23 right-eye-dominant (RDE group) participants performed the experiments. Face stimuli were randomly presented in the LVF or right visual field (RVF). The RDE group exhibited significantly larger N170 amplitudes compared with the LDE group. Faces presented in the LVF elicited N170 amplitudes that were significantly more negative in the RDE group than they were in the LDE group, whereas the amplitudes elicited by stimuli presented in the RVF were equivalent between the groups. The LVF superiority was maintained in the RDE group but not in the LDE group. Our results provide the first neural evidence of the DE’s effects on the LVF superiority for faces. We propose that the RDE may be more biologically specialized for face processing.

The left side superiority effect for facial expression perception is not a left visual field superiority effect

The left side superiority effect for facial expression perception is not a left visual field superiority effect

Neural and cognitive face-selective markers: An integrative review

Faces elicit robust and selective neural responses in the primate brain. These neural responses have been investigated with functional MRI and EEG in numerous studies, which have reported face-selective activations in the occipital-temporal cortex and an electrophysiological face-selective response that peaks 170ms after stimulus onset at occipital-temporal sites. Evidence for face-selective processes has also been consistently reported in cognitive studies, which investigated the face inversion effect, the composite face effect and the left visual field (LVF) superiority. These cognitive effects indicate that the perceptual representation that we generate for faces differs from the representation that is generated for inverted faces or non-face objects. In this review, I will show that the fMRI and ERP face-selective responses are strongly associated with these three well-established behavioral face-selective measures. I will further review studies that examined the relationship between fMRI and EEG face-selective measures suggesting that they are strongly linked. Taken together these studies imply that a holistic representation of a face is generated at 170ms after stimulus onset over the right hemisphere. These findings, which reveal a strong link between the various and complementary cognitive and neural measures of face processing, allow to characterize where, when and how faces are represented during the first 200ms of face processing.

The joint development of hemispheric lateralization for words and faces.

Consistent with long-standing findings from behavioral studies, neuroimaging investigations have identified a region of the inferior temporal cortex that, in adults, shows greater face selectivity in the right than left hemisphere and, conversely, a region that shows greater word selectivity in the left than right hemisphere. What has not been determined is how this pattern of mature hemispheric specialization emerges over the course of development. The present study examines the hemispheric superiority for faces and words in children, young adolescents and adults in a discrimination task in which stimuli are presented briefly in either hemifield. Whereas adults showed the expected left and right visual field superiority for face and word discrimination, respectively, the young adolescents demonstrated only the right-field superiority for words and no field superiority for faces. Although the children's overall accuracy was lower than that of the older groups, like the young adolescents, they exhibited a right visual field superiority for words but no field superiority for faces. Interestingly, the emergence of face lateralization was correlated with reading competence, measured on an independent standardized test, after regressing out age, quantitative reasoning scores, and face discrimination accuracy. Taken together, these findings suggest that the hemispheric organization of face and word recognition do not develop independently and that word lateralization, which emerges earlier, may drive later face lateralization. A theoretical account in which competition for visual representations unfolds over the course of development is proposed to account for the findings.

Motivation, affect, and hemispheric asymmetry: Power versus affiliation.

In 4 experiments, the authors examined to what extent information related to different social needs (i.e., power vs. affiliation) is associated with hemispheric laterality. Response latencies to a lateralized dot-probe task following lateralized pictures or verbal labels that were associated with positive or negative episodes related to power, affiliation, or achievement revealed clear-cut laterality effects. These effects were a function of need content rather than of valence: Power-related stimuli were associated with right visual field (left hemisphere) superiority, whereas affiliation-related stimuli were associated with left visual field (right hemisphere) superiority. Additional results demonstrated that in contrast to power, affiliation primes were associated with better discrimination between coherent word triads (e.g., goat, pass, and green, all related to mountain) and noncoherent triads, a remote associate task known to activate areas of the right hemisphere.

Neural correlates of the left-visual-field superiority in face perception appear at multiple stages of face processing.

Studies in healthy individuals and split-brain patients have shown that the representation of facial information from the left visual field (LVF) is better than the representation of facial information from the right visual field (RVF). To investigate the neurophysiological basis of this LVF superiority in face perception, we recorded event-related potentials (ERPs) to centrally presented face stimuli in which relevant facial information is present bilaterally (B faces) or only in the left (L faces) or the right (R faces) visual field. Behavioral findings showed best performance for B faces and, in line with the LVF superiority, better performance for L than R faces. Evoked potentials to B, L, and R faces at 100- to 150-msec poststimulus showed no evidence of asymmetric transfer of information between the hemispheres at early stages of visual processing, suggesting that this factor is not responsible for the LVF superiority. Neural correlates of the LVF superiority, however, were manifested in a shorter latency of the face-specific N170 component to L than R faces and in a larger amplitude to L than R faces at 220-280 and 400-600 msec over both hemispheres. These ERP amplitude differences between L and R faces covaried across subjects with the extent to which the face-specific N170 component was larger over the right than the left hemisphere. We conclude that the two hemispheres exchange information symmetrically at early stages of face processing and together generate a shared facial representation, which is better when facial information is directly presented to the right hemisphere (RH; L faces) than to the left hemisphere (LH; R faces) and best when both hemispheres receive facial information (B faces).

Visual-Field Bias in the Judgment of Facial Expression of Emotion

The left and right hemispheres of the brain are differentially related to the processing of emotions. Although there is little doubt that the right hemisphere is relatively superior for processing negative emotions, controversy exists over the hemispheric role in the processing of positive emotions. Eighty right-handed normal male participants were examined for visual-field (left-right) differences in the perception of facial expressions of emotion. Facial composite (RR, LL) and hemifacial (R, L) sets depicting emotion expressions of happiness and sadness were prepared. Pairs of such photographs were presented bilaterally for 150 ms, and participants were asked to select the photographs that looked more expressive. A left visual-field superiority (a right-hemisphere function) was found for sad facial emotion. A hemispheric advantage in the perception of happy expression was not found.

Neuromagnetic signals associated with reading a kanji character formed by combining two kanji radicals

To find out which brain regions are responsible for the mental construction and recognition of a kanji character initiated by visually presented kanji radicals, rather than by information retained in the memory, a left hen radical and the corresponding right tsukuri radical were simultaneously presented randomly to either the left or right visual field of seven subjects. Thirty left hen radicals and the corresponding right tsukuri radicals were prepared as stimuli; this combination formed over 500 real or pseudo kanji characters. Instead of their usual left and right positions, the left hen radical was always presented above the right tsukuri radical. As quickly and correctly as possible, the subjects released a key when two kanji radicals constituted a single real kanji character and released another key otherwise. We recorded neuromagnetic responses as well as accuracy and reaction time. Left visual field superiority was observed as regards accuracy. This is in good agreement with previous neuropsychological results. Equivalent current dipoles were localized mainly in the left and/or right occipitotemporal regions (ventral visual pathways), the bilateral occipitoparietal regions (dorsal visual pathways) including the supramarginal region, and the areas surrounding the left superior temporal cortex. We suggest that these regions are related to reading and the mental construction of a kanji character from its radicals.

Interhemispheric Transfer of Visual, Auditory, Tactile, and Visuomotor Information in Children with Hydrocephalus and Partial Agenesis of the Corpus Callosum

Interhemispheric transfer was examined in 13 normal controls and in 13 children with hydrocephalus and partial agenesis of the corpus callosum involving a missing splenium associated with spina bifida meningomyelocele and aqueductal stenosis. Children with hydrocephalus demonstrated greater left visual-field superiority for forms indicative of difficulty in interhemispheric transfer of visual information. Interhemispheric transfer time (ITT) was somewhat longer in the children with hydrocephalus, but neither the ITT task nor the dichotic listening and tactile naming tasks provided clear evidence of difficulties in callosal transfer. Sensory and perceptual control tasks revealed similar visual acuity and monotic word perception but larger 2-point discrimination thresholds and poorer tactile matching.

Patterns of Perceptual Asymmetry in Processing Facial Expression

The paper reports four visual half-field experiments on the recognition of schematic faces whose emotional expression varied. Experiments I and II tested accuracy of recognition in a match-to-sample task. The results confirmed an overall left visual-field superiority in face recognition, but an analysis of a subset of the stimuli indicated that the direction and magnitude of the perceptual asymmetry depend upon the sign of the emotional expression. A replot of the results based on direct scaling of emotional expression (Experiment III) revealed an asymmetry gradient shifting from a left visual-field superiority for faces displaying friendly, non-aggressive emotions to a right visual-field superiority for faces displaing hostile, aggressive emotions. When the stimuli are rotated 180 degrees the faces lose their emotional expression and no visual half-field asymmetry in recognition was observed in this condition (Experiment IV). It is concluded that emotional signals are processed independently of pattern, object and face recognition, and that the relative contribution of the left and right cerebral hemispheres to processing of emotional signals varies according to the type of emotion displayed.

Lateral asymmetry in identification and expression of facial emotions

Abstract Ninety normal subjects were asked to identify, in a split-plot repeated measures design, photographs displaying facial expression of four negative emotions, sadness, fear, anger, and disgust, presented tachistoscopically. Experimental manipulations involved in visual field (left-right), hemiface composition of expression (normal representation or right-left, left-left, right-right), and task (matching labelling). A left visual field (LVF) superiority was found for identifying the facial emotions; and sad facial emotion was identified with greatest accuracy followed by fear, disgust, and anger. The main effects of facial composite and task remained nonsignificant. However, a taskwise analysis of the data revealed that normal facial representations (RL) were identified with greater accuracy than left-left (LL) or right-right (RR) facial composites in matching task.

Spatial processing laterality and spatial visualization ability: Relations to sex and familial sinistrality variables

Seventy-four right-handed college students were administered the Clockface Reading Latency Task (CRLT) and the Stafford Identical Blocks Test (SEBT). The lateralized tachistoscopic CRLT yielded a significant left visual field superiority, supporting previous research that had suggested it was a sensitive test of right hemisphere superiority for spatial processing. On the SIBT, males scored significantly higher than females, and there was a sex × familial sinistrality (FS) interaction, like that previously reported by McKeever, Seitz, Hoff, Marino, and Diehl (1983). FS also influenced visual field asymmetries on the CRLT; subjects with left-handedness in their families showed smaller asymmetries. No correlation between spatial laterality and spatial ability was found.

Image generation and processing of generated images in the cerebral hemispheres.

Recent computational models describing the contribution of the cerebral hemispheres to visual imagery have suggested an exclusive capacity of the left hemisphere to generate multipart images. A brief review of relevant findings indicates that the evidence presented in support of this suggestion is not entirely compelling; this prompted a reexamination of this issue in a lateral tachistoscopic study on normal adults. Sixteen subjects participated in two experiments in which they had to decide whether or not a lowercase letter contained a segment extending above or below the main body of the letter. This decision was made directly on lowercase letters in one experiment (perceptual task) and on their generated images in the other experiment (imagery task). The quality of the letters (clear or blurred) and the retinal eccentricity of stimulus presentation (small or large) were orthogonally manipulated. The perceptual task yielded no main effect of visual field but a significant interaction of visual field and letter quality. By contrast, the imagery task resulted in a left visual-field superiority but no interaction involving the visual fields--a departure from predictions based on current models of visual imagery. In addition, the pattern of results in the imagery task corresponded to that obtained with blurred letters in the perceptual task, suggesting limitations in spatial resolution of visual images. Implications of these results for models of cerebral lateralization and visual imagery are discussed.

Shift in visual laterality within blocks of trials

Single random polygons were briefly presented for subsequent recognition in either the left or the right visual half-field, randomized within each of three blocks of 40 trials. No overall perceptual asymmetry was found, but the distribution of correct recognitions within a block showed a shift in favor of the right visual field for later as compared to early trials (experiment 1). The shift was due to a systematic improvement of right visual field performance within blocks, left visual field performance remaining unchanged. This effect was replicated in experiment 2 and in the control condition of experiment 3. It was not caused by increasing familiarity of the stimulus material (experiment 2). When an unrelated auditory verbal task was given before each visual trial, an overall right half-field superiority was found, evenly distributed across trials (experiment 3). Thus extraexperimental subverbalization could have primed the left hemisphere in terminal subblocks in the earlier experiments. However, neither of two manipulations designed to preclude subverbalization yielded an overall left half-field superiority (experiment 4). Indeed, precluding subverbalization seemed to improve left hemisphere performance in the present task, in which verbal coding is not useful. Difficulty in demonstrating reliable left visual field superiority for relatively nonverbal stimuli thus does not necessarily reflect weak or unstable specialized processing by the right hemisphere. The same outcome can result from gradual gains in left hemisphere performance within a block of trials. In the present task, for which there is relative right hemisphere specialization, the left hemisphere has the potential to match right hemisphere performance.

Cerebral Lateralisation at Different Stages of Facial Processing

Two experiments are reported which explore the cerebral lateralisation of different stages of facial processing. In Experiment 1 subjects were briefly presented with either upright or inverted Mooney faces to either the left or right visual field. The subjects' task was to decide whether or not the stimulus had the configuration of a face. The data showed a left visual field superiority in performing this task. In Experiment 2 subjects were briefly presented with line drawings of faces to either the left or right visual field. On half the trials all the facial features were intact whilst in the remainder one feature had been replaced by an anomalous feature in the same position. The subjects were required to detect whether an anomalous feature was present or not and this task produced a right visual field superiority. These data argue against a global right hemisphere superiority in facial processing and suggest, instead, that hemispheric superiority will vary depending on the stage of facial analysis investigated. On the basis of these and other recent findings it would appear that the right hemisphere is advantaged for the holistic stages of facial processing whilst the left-hemisphere has superiority for analysis at the level of individual features. However, the data are ambiguous as to whether the hemispheric differences detected reflect facespecific or general processing characteristics of the cerebral hemispheres.

Interhemispheric Asymmetry in Facial Expression Recognition: Relationship to Field-Dependence

Sixty college students, 30 males and 30 females, with a well defined cognitive style (measured by means of three tests), carried out a recognition task of six unambiguous facial expressions which were unilaterally presented in a tachis toscopic condition. A significant left visual field superiority was present for the field independent subjects; a low but significant right visual field superiority was present for the field dependent subjects. No differences were found between the sexes.

Hemispheric differences in the judgment of number

Two manual reaction-time experiments examined visual field differences for the judgment of number. All told, three tasks (recognition/enumeration, magnitude judgment and oddity judgment) were performed on three nonverbal indicators of number (dot clusters, bargraphs and dials) and two verbal indicators (word names of numbers and digits). The results indicated that field differences depended largely on display format, not on the task. Thus, dot clusters, bargraphs and dials all showed a left visual field superiority, while words showed a right visual field superiority. There was no evidence of lateralization for digits.

Effects of visual-field and matching instruction on event-related potentials and reaction time

Vertical letter pairs were presented randomly in the left and right visual hemifields in a physical identity match and name identity match condition. The reaction times showed a right visual field superiority for name matches, and a left visual field superiority for physical matches. Event-related potentials to letter pairs showed a sequence of three waves: a negative wave (N2, around 270 msec), a positive wave (P3, around 500 msec), and a broad positive slow wave (SW, around 600–700 msec), respectively. P3 and SW amplitudes were consistently larger at the left hemisphere than at the right hemisphere, regardless of the field of stimulation. At both hemispheres, N2 waves were always larger to stimuli presented in the visual field contralateral to a hemisphere than stimuli presented in the visual field ipsilateral to a hemisphere. The positive waves (P3, SW) showed the opposite pattern: smaller amplitudes to stimuli that were presented contralaterally than stimuli that were presented ipsilaterally to a given hemisphere. These results were attributed to a shift in sustained negativity on the directly stimulated hemisphere, relative to the indirectly stimulated hemisphere, reflecting either sensory at attentional processes in the posterior cerebral hemispheres.

Hemispheric competence and perceptual confusability.

Hemispheric competence in performing easy and difficult letter classification was examined in an exact replication of a previous experiment by Jonides (1979). The present experiment failed to confirm Jonides's finding of right visual field advantage in conditions of perceptual confusability and left visual field superiority when the stimuli were easily discriminable. The results showed a trend in the opposite direction, but no significant interaction. This divergence is discussed with respect to existing evidence and methodological procedures.

Left Visual Field Superiority in a Letternaming Task for Both Left- and Right-handers

Subjects identified on the basis of sex, handedness, handwriting posture performed a letter-naming task. Single letters were shown briefly in the left or right visual field and the subject was required to name the letter as quickly as possible. Both left- and right-handers had shorter response latencies when the stimulus was presented in the left visual field. Response latency decreased across trials, however, the decrement was largest to right visual field stimuli. In addition, males produced significantly faster reaction than did females.