Effects of processing speed on cerebral asymmetry for left- and right-oriented faces

A free-vision chimeric facial emotion judgment task and a tachistoscopic face-recognition reaction time task were administered to 20 male right-handed subjects. The tachistoscopic task involved judgments of whether a poser in the centrally presented full-face photograph was the same or different poser than in a profile photograph presented in the left or right visual field (LVF, RVF). The free-vision task was that used by J. Levy, W. Heller, M. Banich, and L. Burton (1983, Brain and Cognition, 2, 404-419) and involved judging which of two chimeric faces appeared happier, in which the two chimeras were mirror images of each other and each chimera consisted of a smiling half-face joined at the midline to a neutral half-face of the same poser. For the tachistoscopic task, subjects were divided into groups of Fast and Slow responders by a median split of the mean reaction times. For the Fast subjects, judgments were faster in the LVF than in the RVF, and there was a significant interaction between visual field and profile direction, such that responses were faster for medially oriented profiles; i.e., LVF responses were faster for right-facing than for left-facing profiles, with the reverse relationship in the RVF. The Slow responders did not show these effects. Only the Fast group showed the bias for choosing the chimera with the smile on the left as happier, and mean response speed and the LVF advantage on the tachistoscopic test correlated with the leftward bias on the free-vision task for all subjects combined. It was suggested that overall response speed on the face-matching task reflected the extent to which specialized and more efficient right hemisphere functions were activated.     

Temporal stability and predictive validity of self-assessed hand preference with first and second graders

The test-retest reliability and predictive validity of a five-item hand preference questionnaire (writing, drawing, throwing a baseball, brushing teeth, and cutting with scissors) were investigated in a sample of 80 children attending first and second grade. After 1 month, 81% of the second choices were the same as the first choices. There were interitem differences in the reliabilities of the five items. Writing and drawing hand exhibited the greatest degree of temporal stability. Writing hand was the one task which was significantly related to visual field bias as indexed by a face perception task.     

Familiarity decisions for faces presented to the left and right cerebral hemispheres

Right-handed subjects were asked to decide whether or not faces presented briefly in the RVF or in the LVF were familiar (familiar faces were those of famous people). This task avoids the need for extensive semantic processing or temporary storage involved in conventional naming or identification tasks, and thus eliminates the contribution of such factors to any observed asymmetry. The resulting finding of faster reaction times to LVF faces, with no overall visual hemifield difference in error rates, is taken to indicate a right-hemisphere superiority either in the processes used to construct facial representations or in the accessing of face recognition units, or both.     

Same-sex imitation of and reported agreement with parents and unfamiliar adults

Children aged 7, 10, and 14 were shown sets of photographs of human figures for each of which they made judgments of age or attractiveness. Randomly determined responses appeared under each set of photographs. Half the children were told the responses represented choices of parents and the other half that they represented choices of unfamiliar adults. After the opportunity to imitate, children were asked whom they thought they agreed with the most. Findings indicated only a small, borderline-significant effect for same-sex imitation, but a large, highly significant effect for reported agreement, particularly in the unfamiliar adult condition (p < .001). Discussion centered on two issues: (1) Same-sex effects appear strongest when the act of choosing between adults and the adults' gender are accentuated; and (2) differences between present and previous findings regarding same-sex effects for parents vs unfamiliar adults may relate to the ages of the children investigated.     

Perception of facial expressions

Three studies examined the nature of the contributions of each hemisphere to the processing of facial expressions and facial identity. A pair of faces, the members of which differed in either expression or identity, were presented to the right or left field. Subjects were required to compare the members of the pair to each other (experiments 1 and 2) or to a previously presented sample (experiment 3). The results revealed that both face and expression perception show an LVF superiority although the two tasks could be differentiated in terms of overall processing time and the interaction of laterality differences with sex. No clear-cut differences in laterality emerged for processing of positive and negative expressions.     

Reflex modification by acoustic signals in newborn infants and in adults

This research asked whether the reflexive eyeblink elicited by a tap to the glabella (the flat region of skin between the eyebrows) is modified by acoustic signals which either precede or accompany the tap. Five experiments employing identical reflex modification procedures on neonates and adults suggest developmental differences in processing auditory stimuli. Neonates failed to exhibit reflex inhibition by either prior acoustic or tactile stimuli. Adults exhibited robust reflex inhibition to these same stimuli. Neonates, however, exhibited reliable reflex augmentation when mild (70 dB re: 0.0002 dyne/cm2) tones were presented simultaneously with the tap. For adults, tone intensities of at least 90 dB were necessary to obtain reliable reflex augmentation. The developmental processes implied by these findings are discussed.     

Hemispheric differences in processing emotions and faces.

Visual field differences for the recognition of emotional expression were investigated using a tachistoscopic procedure. Cartoon line drawings of five adult male characters, each with five emotional expressions ranging from extremely positive to extremely negative, were used as stimuli. Single stimuli were presented unilaterally for 85 msec. Subjects (N = 20) were asked to compare this target face to a subsequent centrally presented face and to decide whether the emotional expressions of the two faces, or the character represented by the two faces, were the same or different. Significant left visual field (LVF) superiorities for both character and emotional expression recognition were found. Subsequent analyses demonstrated the independence of these effects. The LVF superiority for emotional judgments was related to the degree of affective expression, but that for character recognition was not. The results of this experiment are consistent with experimental and clinical literature which has indicated a right hemispheric superiority for face recognition and for processing emotional stimuli. The asymmetry for emotion recognition is interpreted as being an expression of the right hemisphere's synthetic and integrative characteristics, its holistic nature, and its use of imagic associations.     

Reading skill and language skill

To learn to read is to acquire a visual language skill which systematically maps onto extant spoken language skills. Some children perform this task quite adeptly while others encounter much difficulty, and it has become a question of both scientific and practical merit to ask why there exists such a range of success in learning to read. Obviously, learning to read places a complex burden on many emerging capacities, and in principle, at least, reading disability could arise at any level from visual perception to general cognition. Yet since reading is parasitic on spoken language, the possibility also exists that reading disability is derived from some subtle difficulty in the language domain. This article reviews some of the many studies which have explored the association between early reading skills and spoken language skills. The focus will be on findings which reveal that when the linguistic short-term memory skills of good and poor beginning readers are critically examined, considerably many, though perhaps not all, poor readers prove to possess subtle deficiencies which correlate with their problems in learning to read.     

Orientation of attention to nonconsciously recognised famous faces

The nonconscious orientation of attention to famous faces was investigated using masked 17 ms stimulus exposure. Each trial presented a simultaneous pair of one famous and one unfamiliar face, matched on physical characteristics, one each in left visual field (LVF) and right visual field (RVF). These were followed by a dot probe in either LVF or RVF to which participants made a speeded two-alternative forced-choice discrimination response. Participants subsequently evaluated the affective valence (good/evil) of the famous persons on a 7-point scale. Higher accuracy of dot probe discrimination in the same visual field (VF) as the famous face suggested that attention was oriented towards faces of persons evaluated “good”, but a reverse orientation effect was observed for those evaluated “evil”. The awareness check presented the same face pairs under the same conditions, and participants were at chance in a task of selecting the famous face in each pair. The results suggest that famous faces can be identified without awareness, and that attention is attracted by the faces of famous persons not regarded as “evil”.     

Laterality effects in identification of caricatures and photographs of famous faces

Recent evidence suggests that memory representations of familiar faces may exaggerate distinctive information as do caricatures (G. Rhodes, S. Brennan, & S. Carey, Cognitive Psychology, 1987). Therefore caricatures should be effective representations of faces and should yield a right hemisphere processing advantage, as do photographs of faces. Photographs and caricatures of famous faces were presented to the left visual (LVF), the right visual field (RVF), and centrally (CVF), in a name-face verification task. There was a LVF (right hemisphere) advantage for both caricatures and photographs on name-face mismatches but no VF difference for matches. These results were true for both accuracy and reaction time. Processing strategy differences that may account for the difference between matches and mismatches are discussed. Performance was generally better for photographs than for caricatures, irrespective of visual field condition.     

An opponent-process theory of motivation: III. Some affective dynamics in imprinting

The theory suggests that for immature precocial birds, the stimulation from an appropriate imprinting object innately arouses a primary effective process that is hedonically pleasant. The occurrence of this process automatically generates (via an opponent loop system) an opponent-process which is hedonically unpleasant. When the imprinting object is withdrawn, the primary process rapidly terminates, but the opponent-process persists, unopposed, for some time. By assuming that the opponent-process becomes stronger with its repeated (or prolonged) arousal, it is possible to account for many of the motivational factors in imprinting. These include: (1) the pattern of distress vocalization that occurs when an imprinting object is first presented to and then withdrawn from newly hatched ducklings, (2) the reinforcement and punishment effects that characterize imprinting, and (3) the priming effects that occur in the context of imprinting.     

Valence specific laterality effects in free viewing conditions: the role of expectancy and gender of image

Recent research has looked at whether the expectancy of an emotion can account for subsequent valence specific laterality effects of prosodic emotion, though no research has examined this effect for facial emotion. In the study here (n=58), we investigated this issue using two tasks; an emotional face perception task and a novel word task that involved categorising positive and negative words. In the face perception task a valence specific laterality effect was found for surprise (positive) and anger (negative) faces in the control but not expectancy condition. Interestingly, lateralisation differed for face gender, revealing a left hemisphere advantage for male faces and a right hemisphere advantage for female faces. In the word task, an affective priming effect was found, with higher accuracy when valence of picture prime and word target were congruent. Target words were also responded to faster when presented to the LVF versus RVF in the expectancy but not control condition. These findings suggest that expecting an emotion influences laterality processing but that this differs in terms of the perceptual/experience dimension of the task. Further, that hemispheric processing of emotional expressions appear to differ in the gender of the image.     

自动情绪调节对负性情绪面孔注意偏向的影响

本研究通过成语匹配任务启动情绪调节目标,在情绪flanker任务中考察了自动情绪调节启动对注意偏向的影响。结果表明,中性启动条件下,被试表现出对负性情绪面孔的注意偏向,而情绪调节启动条件下,被试对正性、负性情绪面孔的注意分配不存在显著差异。这一结果说明自动情绪调节可以有效地减弱被试的负性情绪面孔注意偏向。     

Categorizing facial identities, emotions, and genders: attention to high- and low-spatial frequencies by children and adults

Three age groups of participants (5-6 years, 7-8 years, adults) matched faces on the basis of facial identity. The procedure involved either low- or high-pass filtered faces or hybrid faces composed from two faces associated with different spatial bandwidths. The comparison stimuli were unfiltered faces. In the three age groups, the data indicated a significant bias for processing of low-pass information in priority. In a second task, participants were asked to identify the emotion (smiling or grimacing) or gender (male or female) of hybrid high-pass/low-pass faces. Opposite results emerged in the two tasks irrespective of the age group; the gender discrimination task indicated a bias for low-pass information, and the emotion task indicated a bias for high-pass information. These differences suggest independent processing routes for functionally different types of information such as emotion, gender, and identity. These routes are already established by 5 years of age.     

Valence specific laterality effects in free viewing conditions: The role of expectancy and gender of image

Recent research has looked at whether the expectancy of an emotion can account for subsequent valence specific laterality effects of prosodic emotion, though no research has examined this effect for facial emotion. In the study here (n = 58), we investigated this issue using two tasks; an emotional face perception task and a novel word task that involved categorising positive and negative words. In the face perception task a valence specific laterality effect was found for surprise (positive) and anger (negative) faces in the control but not expectancy condition. Interestingly, lateralisation differed for face gender, revealing a left hemisphere advantage for male faces and a right hemisphere advantage for female faces. In the word task, an affective priming effect was found, with higher accuracy when valence of picture prime and word target were congruent. Target words were also responded to faster when presented to the LVF versus RVF in the expectancy but not control condition.These findings suggest that expecting an emotion influences laterality processing but that this differs in terms of the perceptual/experience dimension of the task. Further, that hemispheric processing of emotional expressions appear to differ in the gender of the image.     

About face: left-hemisphere involvement in processing physiognomies

Three experiments were concluded to investigate the involvement of the two cerebral hemispheres in processing faces. Perceptual discrimination of pairs of faces was equally speedy overall when the stimuli were presented in the right visual field (RVF) or left visual field (LVF). For faces differing in one or two features, however, a qualitatively different pattern of results was obtained for the two visual fields, and an RVF advantage emerged when the difference lay in the upper part of the faces (Experiment 1). An examination of the discriminability of the facial features from which the faces were constructed (Experiment 2) showed that the processes involved in RVF comparisons of faces were not dependent on the saliency of the features but, rather, followed a top-to-bottom serial analysis of the stimuli; the speed of the processing involved in LVF presentations was a function of the degree of similarity of the different comparison faces. Evidence for a serial type of comparison faces were used (Experiment 3). It was concluded that even though comparisons were equally speedy overall in LVF and RVF presentations, qualitatively different processes take place in the two hemispheres, which prove competent at processing faces, each in its own way. Some methodological problems inherent in tachistoscopic studies are discussed, and it is proposed that the quality of the stimulus representation achieved or required for cognitive processing may be determinant in the emergence of functional hemispheric asymmetries.     

Lack of an Attention Bias Away From Relatively Negative Faces in Dysphoria Is Not Related to Biased Emotion Identification

Eye-tracking-based attention research has consistently shown a lack of a normative attentional bias away from dysphoric face stimuli in depression, characterizing the attention system of non-depressed individuals. However, this more equal attention allocation pattern could also be related to biased emotion identification, namely, an inclination of depressed individuals to attribute negative emotions to non-negative stimuli when processing mood-congruent stimuli. Here, we examined emotion identification as a possible mechanism associated with attention allocation when processing emotional faces in depression. Attention allocation and emotion identification of participants with high (HD; n = 30) and low (LD; n = 30) levels of depression symptoms were assessed using two corresponding tasks previously shown to yield significant findings in depression, using the same face stimuli (sad, happy, and neutral faces) across both tasks. We examined group differences on each task and possible between-task associations. Results showed that while LD participants dwelled longer on relatively positive faces compared with relatively negative faces on the attention allocation task, HD participants showed no such bias, dwelling equally on both. Trait anxiety did not affect these results. No group differences were noted for emotion identification, and no between-task associations emerged. Present results suggest that depression is characterized by a lack of a general attention bias toward relatively positive faces over relatively negative faces, which is not related to a corresponding bias in emotion identification.     

Asymmetries in face processing: Evidence for a right hemisphere perceptual advantage

Investigation of lateral performance asymmetries in the early stages of face processing was conducted using a task which avoided the need either to memorise or to compare two faces. Subjects were merely required to decide whether or not a laterally presented stimulus constituted a face. Analysis of the latencies indicated a LVF advantage for this task which is interpreted, in conjunction with the evidence from patients suffering from prosopagnosia, as indicating a right hemisphere superiority in synthesizing facial percepts.     

Conscious and unconscious processing of facial expressions: Evidence from two split‐brain patients

We investigated how the brain's hemispheres process explicit and implicit facial expressions in two ‘split‐brain’ patients (one with a complete and one with a partial anterior resection). Photographs of faces expressing positive, negative or neutral emotions were shown either centrally or bilaterally. The task consisted in judging the friendliness of each person in the photographs. Half of the photograph stimuli were ‘hybrid faces’, that is an amalgamation of filtered images which contained emotional information only in the low range of spatial frequency, blended to a neutral expression of the same individual in the rest of the spatial frequencies. The other half of the images contained unfiltered faces. With the hybrid faces the patients and a matched control group were more influenced in their social judgements by the emotional expression of the face shown in the left visual field (LVF). When the expressions were shown explicitly, that is without filtering, the control group and the partially callosotomized patient based their judgement on the face shown in the LVF, whereas the complete split‐brain patient based his ratings mainly on the face presented in the right visual field. We conclude that the processing of implicit emotions does not require the integrity of callosal fibres and can take place within subcortical routes lateralized in the right hemisphere.     

Attentional bias for words and faces in social anxiety

Conflicting findings concerning the nature and presence of attentional bias in social anxiety and social phobia have been reported in the literature. This paper reports the findings of two studies comparing people with high and low social anxiety on dot probe tasks using words, faces photographed in front view, and faces photographed in profile as stimuli. In Study 1 those with high social anxiety displayed an attentional bias towards negative faces. The low social anxiety group showed an attentional bias towards positive faces. No significant effects were observed on the dot probe using words as stimuli. Study 2 used pairs of faces presented in profile as though looking at each other. One of the faces displayed either a positive, negative or neutral expression. The second face always had a neutral expression, and in half of the trials it was the subject's own face. The findings of this more ecologically valid procedure replicated those of Study 1. Facilitated attention to dots following emotional faces was specific to threatening facial stimuli. From these studies it appears that the facial dot probe task is a more sensitive index of attentional bias than the word task in a non-clinical sample with social anxiety.