Effects of a concurrent memory task on hemispheric asymmetries in categorization

Recent research on the division of processing between the two cerebral hemispheres has often employed two concurrent tasks to investigate the dynamic nature of hemispheric asymmetries. The experiment reported here explored the effects of two concurrent high-level cognitive tasks (memory retention and semantic categorization) on the direction and magnitude of hemispheric differences in the processing of words and pictures. Subjects were required to categorize words and pictures presented to either the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH). The categorization could be performed while holding either verbal material in memory (digit span), pictorial material in memory (serial nonsense figure recognition), or with no concurrent memory task. The effects produced hemisphere-specific, material-nonspecific interference. The verbal task removed a RVF-LH advantage at word categorization and enhanced a LVF-RH advantage on picture categorization; the pictorial task interfered with picture categorization in the LVF-RH, while enhancing a RVF-LH advantage at word categorization. The results are discussed in terms of multiple resource models of hemisphere function, capacity limitations, and the functional locus of processing required to produce various dynamic hemispheric effects.     

Hemispheric asymmetry in the processing of negative and positive words: A divided field study

Research on the lateralisation of brain functions for emotion has yielded different results as a function of whether it is the experience, expression, or perceptual processing of emotion that is examined. Further, for the perception of emotion there appear to be differences between the processing of verbal and nonverbal stimuli. The present research examined the hemispheric asymmetry in the processing of verbal stimuli varying in emotional valence. Participants performed a lexical decision task for words varying in affective valence (but equated in terms of arousal) that were presented briefly to the right or left visual field. Participants were significantly faster at recognising positive words presented to the right visual field/left hemisphere. This pattern did not occur for negative words (and was reversed for high arousal negative words). These results suggest that the processing of verbal stimuli varying in emotional valence tends to parallel hemispheric asymmetry in the experience of emotion.     

Hemispheric asymmetry in the processing of negative and positive words: a divided field study

Research on the lateralisation of brain functions for emotion has yielded different results as a function of whether it is the experience, expression, or perceptual processing of emotion that is examined. Further, for the perception of emotion there appear to be differences between the processing of verbal and nonverbal stimuli. The present research examined the hemispheric asymmetry in the processing of verbal stimuli varying in emotional valence. Participants performed a lexical decision task for words varying in affective valence (but equated in terms of arousal) that were presented briefly to the right or left visual field. Participants were significantly faster at recognising positive words presented to the right visual field/left hemisphere. This pattern did not occur for negative words (and was reversed for high arousal negative words). These results suggest that the processing of verbal stimuli varying in emotional valence tends to parallel hemispheric asymmetry in the experience of emotion.     

Individual differences in hedonic capacity,depressed mood,and affective states predict emotional reactivity

Identifying factors that contribute to inter-individual differences in emotional reactivity is central to understanding the basic mechanisms that give rise to adaptive emotion reactivity and to disruptions that may occur in psychopathology. The current study related emotional reactivity in an unselected young adult sample (N?=?101) to individual difference factors relevant to emotional functioning and mood pathology, specifically anhedonia, depressed mood, and current affective state. To assess emotional reactivity, participants rated their emotional responses to 100 pictures from the International Affective Picture System. Increased self-reported anhedonia (i.e. reduced hedonic capacity) predicted blunted emotional reactivity to both positive and negative images, relative to neutral images, while elevated depressed mood predicted potentiated emotional reactivity to negative vs. neutral images. Anhedonia also accounted for far greater variance in emotional reactivity than depressed mood. Further, more positive affective state predicted potentiated reactivity to positive versus neutral images while more negative affective state predicted potentiated reactivity to negative versus neutral images beyond effects of anhedonia and depressed mood. The current study identified separable effects of anhedonia, depressed mood, and current affect on emotional reactivity.     

Hemispheric predominance assessment of phonology and semantics: a divided visual field experiment

The aim of the present behavioural experiment was to evaluate the most lateralized among two phonological (phoneme vs. rhyme detection) and the most lateralized among two semantic ("living" vs. "edible" categorization) tasks, within the dominant hemisphere for language. The reason of addressing this question was a practical one: to evaluate the degree of the hemispheric lateralization for several language tasks, by using the divided visual presentation of stimuli, and then choose the most lateralized semantic and phonological for mapping language in patients by using fMRI in future studies. During the divided visual field experiment by using words (semantic tasks) and pseudo-words (phonological tasks) as stimuli, thirty-nine right-handed participants were examined. Our results have shown that all tasks were significantly left hemisphere lateralized. Furthermore, the rhyme was significantly more lateralized than phoneme detection and "living" was significantly more lateralized than "edible" categorization. The rhyme decision and "living" categorization will be used in future fMRI studies for assessing hemispheric predominance and cerebral substrate for semantics and phonology in patients. Our results also suggest that the characteristics of stimuli could influence the degree of the hemispheric lateralization (i.e., the emotional charge of stimuli for words and the position of the phoneme to be detected, for pseudo-words).     

The effects of valence‐based and discrete emotional states on aesthetic response

There is increasing recognition that consumer aesthetics—the responses of consumers to the aesthetic or appearance aspects of products—has become an important area of marketing in recent years. Consumer aesthetic responses to a product are a source of pleasure for the consumer. Previous research into the aesthetic responses to products has often emphasized exterior factors and visual design, but studies have seldom considered the psychological aesthetic experience of consumers, and in particular their emotional state. This study attempts to bridge this gap by examining the link between consumers’ emotions and their aesthetic response to a product. Thus, the major goal of this study was to determine how valence‐based and discrete emotional states influence choice. In Studies 1 and 2, positive and negative emotions were manipulated to implement two different induction techniques and explore the effect of emotions on participants’ choices in two separate experiments. The results of both experiments confirmed the predictions, indicating that aesthetic responses and purchase intention are functions of emotional valence, such that both are stronger for people in a positive emotional state than for those in a negative emotional state. Study 2 also used a neutral affective state to establish the robustness of this observed effect of incidental affect. The results of Study 3 demonstrate that aesthetic response and purchase intention are not only a function of affect valence, but also are affected by the certainty appraisal associated with specific affective states. This research, therefore, contributes to the literature by offering empirical evidence that incidental affect is a determinant of aesthetic response.     

The impact of rewards on empathic accuracy and emotional mimicry

The notion that motivation influences empathic accuracy has been inferred from aspects of the task, the situation or the relationship between interaction partners or between groups. The present research assessed whether monetary reward influences cognitive and affective empathy. In Study 1, cognitive empathy was assessed for 42 participants who decoded briefly (33 ms) presented expressions of sadness and anger. For half the participants, correctly decoded expressions on male faces were rewarded, for the other half correctly decoded expressions on female faces were rewarded. The results showed that rewards increase empathic accuracy for both emotions equally. In Study 2, facial EMG was measured as well to assess emotional mimicry as an index of affective empathy. Study 2 replicated the findings from Study 1 and found a moderation of affective empathy as indexed through facial mimicry for sadness. Thus, simple monetary rewards affect both cognitive and affective empathy.     

Hemispheric specialization for emotional word processing is a function of SSRI responsiveness

Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right hemisphere (RH) relative to left hemisphere (LH) activity. The present study investigated the relationship between hemispheric specialization and processing of emotional words using a divided visual field paradigm administered to never-depressed and previously-depressed individuals, who were subdivided into SSRI responders and non-responders. SSRI responders and never-depressed participants were similar in their left hemispheric lateralization for evaluating emotional words. In contrast, SSRI non-responders showed a relative shift towards RH processing of negative words, and a strong bias toward negative evaluation of words presented to the RH. The results are discussed within the context of a biological-cognitive model of vulnerability to depression.     

领导者情感的作用机制：一个跨层的整合观点

领导者情感能够影响下属个体绩效和团队整体绩效, 但作用机制尚不清晰。基于情感事件理论和情绪传染理论, 在个体层面上, 领导者情感通过情绪传染和领导者行为两条路径影响下属情感, 进而影响下属绩效和工作态度。其次在团队层面上, 个体情感通过情绪传染和交叉影响形成团队情感基调, 通过影响团队过程, 进而影响团队绩效。最后, 文章提出领导者情感的跨层整合模型, 并对未来研究方向进行讨论。     

Cerebral lateralization of language in deaf and hearing people

In Experiment 1 neither hearing nor prelingually deaf signing adolescents showed marked lateralization for lexical decision but, unlike the hearing, the deaf were not impaired by the introduction of pseudohomophones. In Experiment 2 semantic categorization produced a left hemisphere advantage in the hearing for words but not pictures whereas in the deaf words and signs but not pictures showed a right hemisphere advantage. In Experiment 3 the lexical decision and semantic categorization findings were confirmed and both groups showed a right hemisphere advantage for a face/nonface decision task. The possible effect of initial language acquisition on the development of hemispheric lateralization for language is discussed.     

Hemispheric specialization for emotional word processing is a function of SSRI responsiveness

Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right hemisphere (RH) relative to left hemisphere (LH) activity. The present study investigated the relationship between hemispheric specialization and processing of emotional words using a divided visual field paradigm administered to never-depressed and previously-depressed individuals, who were subdivided into SSRI responders and non-responders. SSRI responders and never-depressed participants were similar in their left hemispheric lateralization for evaluating emotional words. In contrast, SSRI non-responders showed a relative shift towards RH processing of negative words, and a strong bias toward negative evaluation of words presented to the RH. The results are discussed within the context of a biological–cognitive model of vulnerability to depression.     

The affective regulation of cognitive priming

Semantic and affective priming are classic effects observed in cognitive and social psychology, respectively. The authors discovered that affect regulates such priming effects. In Experiment 1, positive and negative moods were induced before one of three priming tasks; evaluation, categorization, or lexical decision. As predicted, positive affect led to both affective priming (evaluation task) and semantic priming (category and lexical decision tasks). However, negative affect inhibited such effects. In Experiment 2, participants in their natural affective state completed the same priming tasks as in Experiment 1. As expected, affective priming (evaluation task) and category priming (categorization and lexical decision tasks) were observed in such resting affective states. Hence, the authors conclude that negative affect inhibits semantic and affective priming. These results support recent theoretical models, which suggest that positive affect promotes associations among strong and weak concepts, and that negative affect impairs such associations (Clore & Storbeck, 2006; Kuhl, 2000).     

No pain,no change: Reductions in prior negative affect following physical pain

In general, organisms are motivated to avoid stimuli that induce pain. However, some individuals intentionally inflict pain on themselves (e.g., nonsuicidal self-injury) and report doing so for the perceived emotional benefits following the experience of pain. Two controlled laboratory studies sought to expand upon the relatively limited literature on the effects of pain on emotion. In Study 1, participants provided momentary affect ratings immediately before and after experiencing physical pain. Results demonstrated that both positive affect and negative affect (NA) decreased following the experience of pain. In the Study 2, we examined the effect that individual differences in emotional reactivity had on affective reactions to pain. Individuals high in emotional reactivity experienced larger decreases in NA following the experience of pain than individuals who were low in emotional reactivity. Our findings may potentially explain why some individuals intentionally seek out the experience of pain.     

Sex-related hemispheric lateralization of amygdala function in emotionally influenced memory: an FMRI investigation

The amygdala appears necessary for enhanced long-term memory associated with emotionally arousing events. Recent brain imaging investigations support this view and indicate a sex-related hemispheric lateralization exists in the amygdala relationship to memory for emotional material. This study confirms and further explores this finding. Healthy men and women underwent functional Magnetic Resonance Imaging (fMRI) while viewing a series of standardized slides that were rated by the subjects as ranging from emotionally neutral to highly arousing. Two weeks later, memory for the slides was assessed in an incidental recognition test. The results demonstrate a significantly stronger relationship in men than in women between activity of the right hemisphere amygdala and memory for those slides judged as arousing, and a significantly stronger relationship in women than in men between activity of the left hemisphere amygdala and memory for arousing slides. An ANOVA confirmed a significant interaction between sex and hemisphere regarding amygdala function in memory. These results provide the strongest evidence to date of a sex-related hemispheric lateralization of amygdala function in memory for emotional material. Furthermore, they underscore the view that investigations of neural mechanisms underlying emotionally influenced memory must anticipate, and begin to account for, the apparently substantial influence of sex.     

Hemispheric differences in grammatical class.

Although a number of studies have examined lexical asymmetries in hemispheric processing, few have systematically investigated differences between nouns and verbs. Lateralization effects of grammatical class were examined by presenting nouns and verbs of both high and low frequency to either the right or left visual field. Results from both a noun/verb categorization and a lexical decision task revealed a significant visual field by grammatical class interaction. Further analyses revealed that verbs were processed faster in the left compared to the right hemisphere, while there was no hemispheric advantage for the processing of nouns. The present study provides new evidence for the role of grammatical class in lexical processing.     

Lateralisation of diffuse positive and negative affect: Ascribing valence to ambiguous stimuli

The available evidence regarding the lateralisation of affect is rather divergent. Interestingly, the common procedure in previous research on affective lateralisation has been to measure hemispheric dominance following exposure to concrete affective stimuli. Therefore, prior research seems to tap primarily into the lateralisation of specific approach–avoidance motivations rather than diffuse affective states. The present research adopted an alternative methodological approach that excluded approach–avoidance motivations and merely studied the lateralised nature of diffuse affect. Participants evaluated ambiguous stimuli presented in either the right or left visual field. Results showed that stimuli presented in the left visual field were significantly more often ascribed a positive meaning compared to information in the right visual field. The present findings are compatible with related lateralised processes and underscore the necessity of distinguishing between specific motivations and diffuse affect.     

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.     

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.     

Sex differences in the response to emotional distraction: an event-related fMRI investigation

Evidence has suggested that women have greater emotional reactivity than men. However, it is unclear whether these differences in basic emotional responses are also associated with differences in emotional distractibility, and what the neural mechanisms that implement differences in emotional distractibility between women and men are. Functional MRI recording was used in conjunction with a working memory (WM) task, with emotional distraction (angry faces) presented during the interval between the memoranda and the probes. First, we found an increased impact of emotional distraction among women in trials associated with high-confidence responses, in the context of overall similar WM performance in women and men. Second, women showed increased sensitivity to emotional distraction in brain areas associated with “hot” emotional processing, whereas men showed increased sensitivity in areas associated with “cold” executive processing, in the context of overall similar patterns of response to emotional distraction in women and men. Third, a sex-related dorsal–ventral hemispheric dissociation emerged in the lateral PFC related to coping with emotional distraction, with women showing a positive correlation with WM performance in left ventral PFC, and men showing similar effects in the right dorsal PFC. In addition to extending to men results that have previously been reported in women, by showing that both sexes engage mechanisms that are similar overall in response to emotional distraction, the present study identifies sex differences in both the response to and coping with emotional distraction. These results have implications for understanding sex differences in the susceptibility to affective disorders, in which basic emotional responses, emotional distractibility, and coping abilities are altered.     

An examination of the right-hemisphere hypothesis of the lateralization of emotion

The Right-Hemisphere Hypothesis posits that emotional stimuli are perceived more efficiently by the right hemisphere than by the left hemisphere. The current research examines this hypothesis by examining hemispheric asymmetries for the conscious and unconscious perception of emotional stimuli. Negative, positive, and neutral words were presented for 17 ms to one visual field or the other. Conscious perception was measured by using a subjective report-of-awareness measure reported by participants on each trial. Unconscious perception was measured using an "exclusion task," a form of word-stem-completion task. Consistent with previous research, there was a right-hemisphere advantage for the conscious perception of negative information. As in previous studies, this advantage for conscious perception occurred at the expense of unconscious perception. Specifically, there was a right-hemisphere inferiority for the unconscious perception of negative information. Contrary to the predictions of the Right-Hemisphere Hypothesis, there were no hemispheric asymmetries for the perception of positive emotional information, thus suggesting that the Right-Hemisphere Hypothesis may not be applicable to all behavioral studies.