情绪评价任务中抑郁个体的分心抑制机制实验研究

本实验使用情绪负启动技术,在情绪评价任务中考察了抑郁个体和正常被试对正、负情绪词分心抑制方面的差异。结果显示,与控制条件下相比,非抑郁控制组被试在负启动条件下对探测显示中正、负性靶子词的反应时间更长;抑郁个体只表现在对探测显示中正性靶子词反应时的延长,负性靶子词未出现负启动效应。结果说明,抑郁个体对负性信息存在抑制机制障碍,对负性信息的偏向与选择性注意中的维持成分有关。这提示心理治疗家应该注重训练抑郁个体对负性信息的抑制能力,预防抑郁复发的目标应集中在注意持续的控制上。     

Affective Priming Effects in the Left and Right Cerebral Hemispheres in Patients With Alzheimer's Disease

Alzheimer’s disease (AD) patients and control subjects were tested in an affective priming paradigm associated with an affective discrimination task. Two pictures, one affectively positive or affectively negative and the other neutral, were presented simultaneously in the right and in the left visual fields; the participants had to decide which of the two pictures was the most affectively positive or negative. The target pictures were preceded by a prime picture that was either affectively positive, affectively negative, or neutral. The principal result was the observation, in AD patients as well as in control subjects, of negative affective priming effects for targets presented in the right hemisphere, and of positive affective priming effects for targets presented in the left hemisphere. The presence of affective priming effects suggests that AD patients have no particular deficit in the automatic activation of emotional information; the fact that priming effects were also observed for targets presented in the left hemisphere showed that AD patients probably have no left hemisphere deficit in the automatic activation of emotional information. However, in AD patients, affective priming effects were significant with negative targets but not with positive targets, which could suggest that AD patients processed positive targets in a more semantic way than negative targets.     

Form-specific visual priming in the right cerebral hemisphere.

Results of 4 experiments indicate that both within-modality and case-specific visual priming for words are greater when test stimuli are presented initially to the right cerebral hemisphere (RH). In contrast, neither within-modality nor case-specific explicit memory for words is greater when stimuli are presented initially to the RH. Priming is measured using word-stem completion, and explicit memory is measured using word-stem cued recall. In both cases, Ss first rate how much they like words, and then word stems are presented briefly to the RH (in the left visual field) or to the left hemisphere (in the right visual field). Results suggest that at least 2 separate systems encode the visual representations that produce priming. The system that is more effective in the RH is better at representing form-specific information, whereas another system that is not more effective in the RH does not distinguish among distinct instances of word forms.     

Understanding metaphoric sentences in the two cerebral hemispheres

Previous studies indicate that the right hemisphere (RH) has a unique role in maintaining activation of metaphoric single word meanings. The present study investigated hemispheric asymmetries in comprehending metaphoric word meanings within a sentence context. Participants were presented with incomplete priming sentences followed by (literally) true, false, or metaphoric lateralized target words and were asked to decide whether each sentence is literally true or false. Results showed that responses to metaphoric sentences were slower and less accurate than to false sentences when target words were presented to the right visual field (RVF)-LH as well as to the left visual field (LVF)-RH. This suggests that the understanding of lexical metaphors within a sentence context involves LH as well as RH processing mechanisms and that the role of each hemisphere in processing nonliteral language is flexible and may depend on the linguistic task at hand.     

What is the role of affect in the spacing effect?

In Experiments 1 and 2, after studying a list containing connotatively neutral words that were presented once or were presented at various spacing intervals, subjects either attempted free recall or made affective judgments of the study-list targets along a pleasant/unpleasant dimension. Spacing effects occurred in recall, and massed items were judged to be more unpleasantthan once-presented and spaced words. In the third experiment, subjects studied homogeneous lists composed of either connotatively good words or connotativelybad ones. Spacing effects were absent in the recall of both types of words because massed-practice words were recalled at a high level, one that was about the same as that for spaced-practice words. Affective judgments were unrelated to presentation condition, and both good and bad massed words were judged to be positive in affect. Although the data suggest that different study conditions can lead to different affective reactions, the results are moot with regard to the relationship between affect and the magnitude of spacing effects.     

Right hemisphere involvement in the attentional blink: evidence from a split-brain patient

When two masked targets are presented in a rapid sequence, correct identification of the first hinders identification of the second. This attentional blink (AB) is thought to be the result of capacity limitations in visual information processing. Neuropsychological and neuroimaging evidence implicated the right hemisphere as the source of this processing limitation. We investigated this idea by testing a split-brain patient (JW) in a modified AB task. The targets were presented in the same visual field (VF), and thereby to the same hemisphere, or in different VFs. We observed evidence of an AB both when the targets were presented to the same hemisphere and when the targets were presented to different hemispheres. However, the AB was more severe when the second target was presented to the RH. Our results are consistent with the notion that the right hemisphere plays a critical, but not unique, role in limited-capacity visual processing.     

Priming nouns and verbs: differential influences of semantic and grammatical cues in the two cerebral hemispheres

The current experiment investigated how sentential form-class expectancies influenced lexical-semantic priming within each hemisphere. Sentences were presented that led readers to expect a noun or a verb and the sentence-final target word was presented to one visual field/hemisphere for a lexical decision response. Noun and verb targets in the semantically related condition were compared to an unrelated prime condition, which also predicted part of speech but did not contain any lexical-semantic associates of the target word. The semantic priming effect was strongly modulated by form-class expectancy for RVF/LH targets, for both nouns and verbs. In the LVF/RH, semantic priming was obtained in all conditions, regardless of whether the form-class expectancy was violated. However, the nouns that were preceded by a noun-predicting sentence showed an extremely high priming value in the LVF/RH, suggesting that the RH may have some sensitivity to grammatical predictions for nouns. Comparisons of LVF/RH priming to calculations derived from the LSA model of language representation, which does not utilize word order, suggested that the RH might derive message-level meaning primarily from lexical-semantic relatedness.     

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.     

Aphasic patients exhibit a reversal of hemispheric asymmetries in categorical color discrimination

Patients with left hemisphere (LH) or right hemisphere (RH) brain injury due to stroke were tested on a speeded, color discrimination task in which two factors were manipulated: (1) the categorical relationship between the target and the distracters and (2) the visual field in which the target was presented. Similar to controls, the RH patients were faster in detecting targets in the right visual field when the target and distracters had different color names compared to when their names were the same. This effect was absent in the LH patients, consistent with the hypothesis that injury to the left hemisphere handicaps the automatic activation of lexical codes. Moreover, the LH patients showed a reversed effect, such that the advantage of different target-distracter names was now evident for targets in the left visual field. This reversal may suggest a reorganization of the color lexicon in the right hemisphere following left hemisphere brain injury and/or the unmasking of a heightened right hemisphere sensitivity to color categories.     

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.     

Hemispheric asymmetries for selective attention apparent only with increased task demands in healthy participants

This study examined the possibility that lack of behavioral evidence indicating hemispheric specialization for selective attention in healthy individuals is due to the use of tasks that are not sufficiently demanding to require selective attention. In a group of 43 participants (ages 17-23), we compared selective attention on a cued-response time task when the target was presented alone and when a distractor was simultaneously presented. The costs of invalid cueing were minimal when the right hemisphere (RH) processed the target relative to when the left hemisphere (LH) processed the target, but only for the high load condition. These results are interpreted as RH specialization in light of evidence suggesting that the RH can direct attention to a larger portion of the visual field.     

Hemispheric differences in specificity effects in talker identification

In the visual domain, Marsolek and colleagues (1999, 2008) have found support for two dissociable and parallel neural subsystems underlying object and shape recognition: an abstract-category subsystem that operates more effectively in the left cerebral hemisphere (LH), and a specific-exemplar subsystem that operates more effectively in the right cerebral hemisphere (RH). Evidence of this asymmetry has been observed in priming specificity for linguistic (words, pseudoword forms) and nonlinguistic (objects) stimuli. In the auditory domain, the authors previously found hemispheric asymmetries in priming effects for linguistic (spoken words) and nonlinguistic (environmental sounds) stimuli. In the present study, the same asymmetrical pattern was observed in talker identification by means of two long-term repetition-priming experiments. Both experiments consisted of a familiarization phase and a final talker identification test phase, using sentences as stimuli. The results showed that specificity effects (an advantage for same-sentence priming, relative to different-sentence priming) emerged when the target stimuli were presented to the left ear (RH), but not when the target stimuli were presented to the right ear (LH). Taken together, this consistent asymmetrical pattern of data from both domains-visual and auditory-may be indicative of a more general property of the human perceptual processing system. Theoretical implications are discussed.     

Automatic semantic priming in the left and right hemispheres

We investigated hemispheric differences and inter-hemispheric transfer of facilitation in automatic semantic priming, using prime-target pairs composed of words of the same category but not associated (e.g. skirt-glove), and a blank-target baseline condition. Reaction time and accuracy were measured at short (300 ms) intervals between prime and target onsets, using a go/no-go task to discriminate between word or non-word targets. Reaction times were facilitated more for target words presented in the right visual field (RVF) compared to the left visual field (LVF), and targets presented in RVF were primed in both visual fields, whereas targets presented in LVF were primed by primes in the LVF only. These results suggest that both hemispheres are capable of automatic priming at very short stimulus onset asymmetries (SOA), but cross-hemisphere priming occurs only in the left hemisphere.     

An inter-hemispheric imbalance in the psychopath’s brain

Psychopathy is associated with two extremities. On the one hand, psychopathic individuals lack any concern for social norms and they are severely poor in maintaining healthy social relationships. In addition, the ability of individuals with psychopathy to feel certain emotions such as empathy, guilt or fear is seriously compromised. In contrast to these deficits, some behaviors and tendencies are exaggerated in psychopathy. For instance, psychopathic individuals display higher than normal impulsivity, stimulation-seeking, aggression and risk-taking. There are indications in the literature that pro-social behavior, as well as the feelings of empathy, guilt and fear are mediated predominantly by regions within the right hemisphere (RH), whereas impulsivity, stimulation-seeking, aggression and risk-taking are linked primarily with left hemisphere (LH) activity. From a neurobiological perspective, it seems that psychopathy may be associated with an altered and imbalanced inter-hemispheric dynamics; a relatively hyperfunctioning LH and/or a hypofunctioning RH. Furthermore, within the psychopathic population, the RH hypofunctioning is more characteristic of primary psychopathy with its affective and interpersonal deficits, while the LH hyperfunctioning is most typical of the secondary psychopathy which is marked by impulsivity and antisocial style.     

Automatic semantic association between emotional valence and brightness in the right hemisphere

Positive words (e.g., faith) were recognised better when presented in white fonts than in black fonts, whereas the opposite was true for negative words (e.g., enemy). A neural basis for this type of association between emotional valence and brightness was investigated using a visual half-field paradigm. Positive and negative words were presented in black or white fonts and presented to the left visual field–right hemisphere (LVF–RH) or right visual field–left hemisphere (RVF–LH) in a word valence judgement task (i.e., positive vs. negative). A cross-over interaction between emotional valence and brightness was observed; valence judgements were facilitated when a positive word appeared in white and when a negative word appeared in black. This interaction was qualified by a higher-order interaction. The cross-over interaction appeared only for LVF–RH trials, suggesting that the right hemisphere was responsible for the association between emotional valence and brightness.     

The effect of depressed mood on the interpretation of ambiguity,with and without negative mood induction

Is there an effect of depressed mood on the interpretation of ambiguity? Are depressed individuals biased to interpret ambiguous information in a negative manner? We used a cross-modal semantic priming task to look for evidence of a negative interpretative bias. Participants listened to ambiguous prime sentences (e.g., Joan was stunned by her final exam mark) and made lexical decisions to target words presented immediately after the sentence offset or after a delay of 1000 ms or 2000 ms. For the semantically related targets, the target was negatively related (distress), positively related (success), or neutrally related (grades) to the ambiguous prime. The experiment was conducted with and without a negative mood induction. The expectation was that depressed participants would be more likely to consider the negative interpretations of the ambiguous primes and would therefore experience larger priming effects for negatively related targets. Although there were large priming effects for all semantically related targets, there was no evidence of a negative interpretative bias.     

The right hemisphere maintains solution-related activation for yet-to-be-solved problems

In five experiments, we examined the time course of hemispheric differences in solution activation for insight-like problems. We propose that solving insight problems requires retrieval of unusual interpretations of problem elements, and that right-hemisphere (RH) coarse semantic coding is more likely than left-hemisphere (LH) fine semantic coding to maintain semantic activation of such interpretations. In four experiments, participants attempted word problems for 7 sec (Experiments 1A and 1B) or 2 sec (Experiments 2A and 2B), and 750 msec later responded to lateralized target words. After 7 sec of solving effort, Experiment 1A participants showed greater solution-related priming (i.e., they named solutions faster than unrelated words) for left visual field-RH (lvf-RH) targets than for right visual field-LH (rvf-LH) targets, and Experiment 1B participants made faster solution decisions on target words presented to the RH, as previously demonstrated following 15 sec of effort. After 2 sec of solving effort in Experiment 2A, women showed symmetric solution-related priming, although men showed a slight lvf-RH advantage in priming; and in Experiment 2B participants made equally quick solution decisions for targets presented to the LH and to the RH. In Experiment 3, participants viewed the problems for 1,250 msec then named lateralized target words; they showed symmetric solution-related priming. These experiments demonstrate solution activation initially in both hemispheres, but maintained solution activation only in the RH.     

Semantic and associative priming in the cerebral hemispheres: some words do, some words don't ... sometimes, some places

This study investigated spreading activation for words presented to the left and right hemispheres using an automatic semantic priming paradigm. Three types of semantic relations were used: similar-only (Deer-Pony), associated-only (Bee-Honey), and similar + associated (Doctor-Nurse). Priming of lexical decisions was symmetrical over visual fields for all semantic relations when prime words were centrally presented. However, when primes and targets were lateralized to the same visual field, similar-only priming was greater in the LVF than in the RVF, no priming was obtained for associated-only words, and priming was equivalent over visual fields for similar + associated words. Similar results were found using a naming task. These findings suggest that it is important to lateralize both prime and target information to assess hemisphere-specific spreading activation processes. Further, while spreading activation occurs in either hemisphere for the most highly related words (those related by category membership and association), our findings suggest that automatic access to semantic category relatedness occurs primarily in the right cerebral hemisphere. These results imply a unique role for the right hemisphere in the processing of word meanings. We relate our results to our previous proposal (Burgess & Simpson, 1988a; Chiarello, 1988c) that there is rapid selection of one meaning and suppression of other candidates in the left hemisphere, while activation spreads more diffusely in the right hemisphere. We also outline a new proposal that activation spreads in a different manner for associated words than for words related by semantic similarity.     

高社交焦虑个体对正性面孔的解释偏差

本研究采用情绪启动范式考察社交焦虑个体对正性刺激解释偏差。研究以正性和打碎的面孔为启动项,正性或负性非社交词为目标项,要求高社交焦虑组被试和控制组被试判断目标项的情感色彩,并记录其反应时与准确率。结果发现,两组被试具有不同的情绪启动模式：高焦虑组被试未表现出显著地相容性效应;他们在正性-正性条件下的反应时显著慢于控制组被试。研究结果提示高社交焦虑个体具有对正性社交刺激的解释偏差,他们不能充分理解正性社交刺激的积极含义。     

Evaluating a split processing model of visual word recognition: effects of orthographic neighborhood size

The split fovea theory proposes that visual word recognition of centrally presented words is mediated by the splitting of the foveal image, with letters to the left of fixation being projected to the right hemisphere (RH) and letters to the right of fixation being projected to the left hemisphere (LH). Two lexical decision experiments aimed to elucidate word recognition processes under the split fovea theory are described. The first experiment showed that when words were presented centrally, such that the initial letters were in the left visual field (LVF/RH), there were effects of orthographic neighborhood, i.e., there were faster responses to words with high rather than low orthographic neighborhoods for the initial letters ('lead neighbors'). This effect was limited to lead-neighbors but not end-neighbors (orthographic neighbors sharing the same final letters). When the same words were fully presented in the LVF/RH or right visual field (RVF/LH, Experiment 2), there was no effect of orthographic neighborhood size. We argue that the lack of an effect in Experiment 2 was due to exposure to all of the letters of the words, the words being matched for overall orthographic neighborhood count and the sub-parts no longer having a unique effect. We concluded that the orthographic activation found in Experiment 1 occurred because the initial letters of centrally presented words were projected to the RH. The results support the split fovea theory, where the RH has primacy in representing lead neighbors of a written word.