The characteristics of non-criminals with high psychopathy traits: Are they similar to criminal psychopaths?

This study compared the findings from a sample of non-criminals with high and low psychopathy levels to published findings with criminal psychopaths and non-psychopaths. Congruent to findings with criminal psychopaths, participants with high psychopathy traits (High-P) compared to those with low psychopathy traits (Low-P) performed significantly worse on the Iowa Gambling Task, a task sensitive to orbital frontal cortex dysfunction. Moreover, the High-P group also evidenced a lack of empathy, a hallmark feature of psychopathy. These findings could not be explained by differences in estimated IQ or performance on a task sensitive to an executive functioning deficit. The discussion focuses on possible differences between non-criminal and criminal psychopaths, concluding criminal psychopaths manifest more extreme degrees of the interpersonal-affective and antisocial features of psychopathy.     

The influence of emotional faces on the spatial allocation of attention

Background objectives: Studies suggest that the right hemisphere is dominant for emotional facial recognition. In addition, whereas some studies suggest the right hemisphere mediates the processing of all emotions (dominance hypothesis), other studies suggest that the left hemisphere mediates positive emotions the right mediates negative emotions (valence hypothesis). Since each hemisphere primarily attends to contralateral space, the goals of this study was to learn if emotional faces would induce a leftward deviation of attention and if the valence of facial emotional stimuli can influence the normal viewer’s spatial direction of attention. Methods: Seventeen normal right handed participants were asked to bisect horizontal lines that had all combinations of sad, happy or neutral faces at ends of these lines. During this task the subjects were never requested to look at these faces and there were no task demands that depended on viewing these faces. Results: Presentation of emotional faces induced a greater leftward deviation compared to neutral faces, independent of where (spatial position) these faces were presented. However, faces portraying negative emotions tended to induce a greater leftward bias than positive emotions. Conclusions: Independent of location, the presence of emotional faces influenced the spatial allocation of attention, such that normal subjects shift the direction of their attention toward left hemispace and this attentional shift appears to be greater for negative (sad) than positive faces (happy).     

Unequal impairment in the recognition of positive and negative emotions after right hemisphere lesions: a left hemisphere bias for happy faces

The processing of several important aspects of a human face was investigated in a single patient (LZ), who had a large infarct of the right hemisphere involving the parietal, and temporal lobes with extensions into the frontal region. LZ showed selective problems with recognizing emotional expressions, whereas she was flawless in recognizing gender, familiarity, and identity. She was very poor in recognizing negative facial expressions (fear, disgust, anger, sadness), but scored as well as the controls on the positive facial expression of happiness. However, in two experiments using both static and dynamic face stimuli, we showed that LZ also did not have a proper notion of what a facial expression of happiness looks like, and could not adequately apply this label. We conclude that the proper recognition of both negative and positive facial expressions relies on the right hemisphere, and that the left hemisphere produces a default state resulting in a bias towards evaluating expressions as happy. We discuss the implications of the current findings for the main models that aim to explain hemispheric specializations for processing of positive and negative emotions.     

Psychopathy and Identification of Facial Expressions of Emotion

The authors examined the association between psychopathy and identification of facial expressions of emotion. Previous research in this area is scant and has produced contradictory findings (Blair et. al., 2001, 2004; Glass & Newman, 2006; Kosson et al., 2002). One hundred and forty-five male jail inmates, rated using the Hare Psychopathy Checklist: Screening Version participated in a facial affect recognition task. Participants were shown faces containing one of five emotions (happiness, sadness, fear, anger, or shame) displayed at one of two different levels of intensity of expression (100% or 60%). The authors predicted that psychopathy would be associated with decreased affect recognition, particularly for sad and fearful emotional expressions, and decreased recognition of less intense displays of facial affect. Results were largely consistent with expectations in that psychopathy was negatively correlated with overall facial recognition of affect, sad facial affect, and recognition of less intense displays of affect. An unexpected negative correlation with recognition of happy facial affect was also found. These results suggest that psychopathy may be associated with a general deficit in affect recognition.     

The valence-specific laterality effect in free viewing conditions: The influence of sex, handedness, and response bias

The right hemisphere has often been viewed as having a dominant role in the processing of emotional information. Other evidence indicates that both hemispheres process emotional information but their involvement is valence specific, with the right hemisphere dealing with negative emotions and the left hemisphere preferentially processing positive emotions. This has been found under both restricted (Reuter-Lorenz & Davidson, 1981) and free viewing conditions (Jansari, Tranel, & Adophs, 2000). It remains unclear whether the valence-specific laterality effect is also sex specific or is influenced by the handedness of participants. To explore this issue we repeated Jansari et al.'s free-viewing laterality task with 78 participants. We found a valence-specific laterality effect in women but not men, with women discriminating negative emotional expressions more accurately when the face was presented on the left-hand side and discriminating positive emotions more accurately when those faces were presented on the right-hand side. These results indicate that under free viewing conditions women are more lateralised for the processing of facial emotion than are men. Handedness did not affect the lateralised processing of facial emotion. Finally, participants demonstrated a response bias on control trials, where facial emotion did not differ between the faces. Participants selected the left-hand side more frequently when they believed the expression was negative and the right-hand side more frequently when they believed the expression was positive. This response bias can cause a spurious valence-specific laterality effect which might have contributed to the conflicting findings within the literature.     

Consequences of brain tumour resection on emotion recognition

Emotion processing impairments are common in patients undergoing brain surgery for fronto-temporal tumour resection, with potential consequences on social interactions. However, evidence is controversial concerning side and site of lesions causing such deficits. This study investigates visual and auditory emotion recognition in brain tumour patients with the aim of clarifying which lesion sites are related to impairments in emotion processing from different modalities. Thirty-four patients were evaluated, before and after surgery, on facial expression and emotional prosody recognition; voxel-based lesion–symptom mapping (VLSM) analyses were performed on patients’ post-surgery MRI images. Results showed that patients’ performance decreased after surgery in both visual and auditory modalities, but, in general, recovered 3 months after surgery. In facial expression recognition, left brain-damaged patients showed greater post-surgery deterioration than right brain-damaged ones, whose performance specifically decreased for sadness and fear. VLSM analysis revealed two segregated areas in the left hemisphere accounting for post-surgery scores for happy (fronto-temporo-insular region) and surprised (middle frontal gyrus and inferior fronto-occipital fasciculus) facial expressions. Our findings demonstrate that surgical removal of tumours in the fronto-temporal region produces impairment in facial emotion recognition with an overall recovery at 3 months, suggesting a partially different representation of positive and negative emotions in the left and right hemispheres for visually – but not auditory – presented emotions; moreover, we show that deficits in specific expression recognition are associated with discrete lesion locations.     

Right hemispheric dominance in processing of unconscious negative emotion

Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects' liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.     

Right hemispheric dominance in processing of unconscious negative emotion

Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects’ liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.     

The relationship of hemispheric preference,as measured by conjugate lateral eye movements,to accuracy of emotional facial expression

This study investigated the relationship between hemispheric preference and communication accuracy of facial affect. Hemispheric preference was determined by rating conjugate lateral eye movements. Forty right-handed females were classified: 10 right-movers (left hemisphere preference), 15 left-movers (right hemisphere preference), and 15 bidirectionals (no hemispheric preference). Subjects were shown emotionally loaded slides portraying happiness, fear, and disgust and their videotaped facial expressions were independently rated for accuracy. It was predicted that negative emotions involved right hemisphere activity and negative affect involved left hemisphere activity. As expected, it was found that left-movers were significantly better than right-movers at nonverbally communicating disgust and fear; hemispheric preference was unrelated to expression of happiness. The accuracy scores of the bidirectionals generally fell in between those of the left-movers and those of the right-movers. The results were discussed in reference to the differential lateralization of positive and negative emotions.This study was conducted as a senior research project by the first author under the supervision of the second author.     

A valence-specific lateral bias for discriminating emotional facial expressions in free field

Findings from subjects with unilateral brain damage, as well as from normal subjects studied with tachistoscopic paradigms, argue that emotion is processed differently by each brain hemisphere. An open question concerns the extent to which such lateralised processing might occur under natural, freeviewing conditions. To explore this issue, we asked 28 normal subjects to discriminate emotions expressed by pairs of faces shown side-by-side, with no time or viewing constraints. Images of neutral expressions were shown paired with morphed images of very faint emotional expressions (happiness, surprise, disgust, fear, anger, or sadness). We found a surprising and robust laterality effect: When discriminating negative emotional expressions, subjects performed significantly better when the emotional face was to the left of the neutral face; conversely, when discriminating positive expressions, subjects performed better when the emotional face was to the right. We interpret this valence-specific laterality effect as consistent with the idea that the right hemisphere is specialised to process negative emotions, whereas the left is specialised to process positive emotions. The findings have important implications for how humans perceive facial emotion under natural conditions.     

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.     

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.     

Cerebellum and processing of negative facial emotions: Cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.     

A Voxel-based lesion study on facial emotion recognition after circumscribed prefrontal cortex damage

Previous studies have shown inconsistent findings regarding the contribution of the different prefrontal regions in emotion recognition. Moreover, the hemispheric lateralization hypothesis posits that the right hemisphere is dominant for processing all emotions regardless of affective valence, whereas the valence specificity hypothesis posits that the left hemisphere is specialized for processing positive emotions while the right hemisphere is specialized for negative emotions. However, recent findings suggest that the evidence for such lateralization has been less consistent. In this study, we investigated emotion recognition of fear, surprise, happiness, sadness, disgust, and anger in 30 patients with focal prefrontal cortex lesions and 30 control subjects. We also examined the impact of lesion laterality on recognition of the six basic emotions. The results showed that compared to control subjects, the frontal subgroups were impaired in recognition of three negative basic emotions of fear, sadness, and anger – regardless of the lesion laterality. Therefore, our findings did not establish that each hemisphere is specialized for processing specific emotions. Moreover, the voxel-based lesion symptom mapping analysis showed that recognition of fear, sadness, and anger draws on a partially common bilaterally distributed prefrontal network.     

Infant and maternal responses to emotional facial expressions: A longitudinal study

The current longitudinal study (N = 107) examined mothers’ facial emotion recognition using reaction time and their infants’ affect-based attention at 5, 7, and 14 months of age using eyetracking. Our results, examining maternal and infant responses to angry, fearful and happy facial expressions, show that only maternal responses to angry facial expressions were robustly and positively linked across time points, indexing a consistent trait-like response to social threat among mothers. However, neither maternal responses to happy or fearful facial expressions nor infant responses to all three facial emotions show such consistency, pointing to the changeable nature of facial emotion processing, especially among infants. In general, infants’ attention toward negative emotions (i.e., angry and fear) at earlier timepoints was linked to their affect-biased attention for these emotions at 14 months but showed greater dynamic change across time. Moreover, our results provide limited evidence for developmental continuity in processing negative emotions and for the bidirectional interplay of infant affect-biased attention and maternal facial emotion recognition. This pattern of findings suggests that infants’ affect-biased attention to facial expressions of emotion are characterized by dynamic changes.     

Facial affect recognition in criminal psychopaths

Prior studies provide consistent evidence of deficits for psychopaths in processing verbal emotional material but are inconsistent regarding nonverbal emotional material. To examine whether psychopaths exhibit general versus specific deficits in nonverbal emotional processing, 34 psychopaths and 33 nonpsychopaths identified with Hare's (R. D. Hare, 1991) Psychopathy Checklist--Revised were asked to complete a facial affect recognition test. Slides of prototypic facial expressions were presented. Three hypotheses regarding hemispheric lateralization anomalies in psychopaths were also tested (right-hemisphere dysfunction, reduced lateralization, and reversed lateralization). Psychopaths were less accurate than nonpsychopaths at classifying facial affect under conditions promoting reliance on right-hemisphere resources and displayed a specific deficit in classifying disgust. These findings demonstrate that psychopaths exhibit specific deficits in nonverbal emotional processing.     

Relationship status moderates avoidant attachment differences in positive emotion decoding accuracy

We investigated attachment differences in the perception of facial emotion expressions. Participants completed a dimensional assessment of adult attachment and recognition accuracy tasks for positive and negative facial emotion expressions. Consistently, avoidant participants who were in romantic relationships, in comparison to singles, had lower decoding accuracy for facial expressions of positive emotions. The results were in line with the hypothesis that being in relationship functions as a naturalistic prime of avoidant persons' defensive tendency to ignore affiliative signals, facial expressions of positive emotion in this instance. The results inform emerging research on attachment and emotion perception by highlighting the role of perceivers' motivated social cognitions.     

The Decoding of Emotional Concepts in Patients with Focal Cerebral Lesions

The effects of focal brain lesions on the decoding of emotional concepts in facial expressions were investigated. Facial emotions are hierarchically organized patterns comprising (1) structural surface features, (2) discrete (primary) emotional categories and (3) secondary dimensions, such as valence and arousal.Categoricaldecoding was measured using (1) selection of category labels and selection of the named emotion category; (2) matching one facial expression with two choice expressions.Dimensionaldecoding was assessed by matching one face with two different expressions with regard to valence or arousal. 70 patients with well documented cerebral lesions and 15 matched hospital controls participated in the study. 27 had left brain damage (LBD; 10 frontal, 10 temporal, 7 parietal); 37 had right brain damage (RBD; 15 frontal, 11 temporal, 11 parietal). Six additional patients had lesions involving both frontal lobes. Right temporal and parietal lesioned patients were markedly impaired in the decoding of primary emotions. The same patients also showed a reduced arousal decoding. In contrast to several patients with frontal and left hemisphere lesions, emotional conceptualization and face discrimination was not independent in these groups. No group differences were observed in valence decoding. However, right frontal lesions appeared to interfere with the discrimination of negative valence. Moreover, a distraction by structural features was noted in RBD when facial identities were varied across stimulus and response pictures in matching tasks with differing conceptual load. Our results suggest that focal brain lesions differentially affect the comprehension of emotional meaning in faces depending on the level of conceptual load and interference of structural surface features.     

The perception of positive and negative facial expressions by unilateral stroke patients

There remains conflict in the literature about the lateralisation of affective face perception. Some studies have reported a right hemisphere advantage irrespective of valence, whereas others have found a left hemisphere advantage for positive, and a right hemisphere advantage for negative, emotion. Differences in injury aetiology and chronicity, proportion of male participants, participant age, and the number of emotions used within a perception task may contribute to these contradictory findings. The present study therefore controlled and/or directly examined the influence of these possible moderators. Right brain-damaged (RBD; n = 17), left brain-damaged (LBD; n = 17), and healthy control (HC; n = 34) participants completed two face perception tasks (identification and discrimination). No group differences in facial expression perception according to valence were found. Across emotions, the RBD group was less accurate than the HC group, however RBD and LBD group performance did not differ. The lack of difference between RBD and LBD groups indicates that both hemispheres are involved in positive and negative expression perception. The inclusion of older adults and the well-defined chronicity range of the brain-damaged participants may have moderated these findings. Participant sex and general face perception ability did not influence performance. Furthermore, while the RBD group was less accurate than the LBD group when the identification task tested two emotions, performance of the two groups was indistinguishable when the number of emotions increased (four or six). This suggests that task demand moderates a study’s ability to find hemispheric differences in the perception of facial emotion.     

Cerebellum and processing of negative facial emotions: cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.