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.     

Processing of pleasant,unpleasant, and neutral words in a lateralised emotional Stroop task

According to the valence hypothesis, pleasant and unpleasant stimuli are mainly processed in the left and in the right hemisphere, respectively. To elucidate whether this reflects lateralised attentional processes, a lateralised Emotional Stroop Task was administered: Pleasant, unpleasant, and neutral words were presented to 63 male and 62 female students in four colours for 150 ms in either the left or the right visual half field. Pleasant words presented in the right (compared to the left) and unpleasant and neutral words presented in the left (compared to the right) visual field had longer latencies. Thus, attentional processes seem to be lateralised, depending on the hedonic tone of the stimuli. Predictions on personality differences in lateralised attentional processes were not confirmed.     

Examining the hemispheric distribution of semantic information using lateralised priming of familiar faces

The way in which the semantic information associated with people is organised in the brain is still unclear. Most evidence suggests either bilateral or left hemisphere lateralisation. In this paper we use a lateralised semantic priming paradigm to further examine this neuropsychological organisation. A clear semantic priming effect was found with greater priming occurring when semantically related prime faces were presented to the left visual field than when presented to the right visual field. Possible explanations for this finding are discussed in terms of the bilateral distribution of different classes of semantic information, a possible role of associative processes within semantic priming and interhemispheric transfer.     

Gender differences in the recognition of laterally presented affective nouns

Evidence suggests that the cerebral hemispheres are differentially specialised for the processing of positively and negatively valenced affective material. The present study examined the consequences of this for the availability in each hemisphere of lexical entries related to positive, neutral, and negative affect. A threshold recognition task was used to assess the identification of positive, neutral, and negative emotionally toned nouns projected to the right or left visual field. A strong lateral asymmetry in favour of right visual field recognition of nouns was observed. Whereas women showed no evidence of changes in lateral asymmetry as a function of affect, lateral asymmetry in men was significantly greater for positive nouns. This finding points to a difference in the representation of affective material in the left and right lexicons of the male brain, and provides support for the notion that gender may be one of the keys to reconciling some of the contradictory findings that characterise this area of research.     

Subliminal mere exposure: specific, general, and diffuse effects

The present research examined the possibility that repeated exposure may simultaneously produce specific and diffuse effects. In Study 1, participants were presented with 5-ms exposures of 25 stimuli each shown once (single-exposure condition) or with five repetitions of 5 stimuli (repeated-exposure condition). Participants in the repeated-exposure condition subsequently rated their own mood more positively than those in the single-exposure condition. Study 2 examined whether affect generated by subliminal repeated exposures transfers to unrelated stimuli. After a subliminal exposure phase, affective reactions to previously exposed stimuli, to new but similar stimuli, and to stimuli from a different category were obtained. Previously exposed stimuli were rated most positively and novel different stimuli least positively. All stimuli were rated more positively in the repeated-exposure condition than in the single-exposure condition. These findings suggest that affect generated by subliminal repeated exposure is sufficiently diffuse to influence ratings of unrelated stimuli and mood.     

沃尔夫假说的新证据:范畴内和范畴间颜色辨别难度相同时语言范畴也会影响注意前颜色知觉

该研究探讨了当范畴内和范畴间颜色的辨别难度相同时,语言范畴是否会影响注意前颜色知觉。实验中,采用渐变且相邻者差别阈限数相当的A、B、C、D四种颜色（前两者为绿色,后两者为蓝色）为刺激材料,并让被试接受视觉Oddball脑电测试。脑电测试分视野给被试呈现标准刺激,以及与标准刺激属同一语言范畴（即颜色词绿色或蓝色）或不同语言范畴的偏差刺激。结果发现：在左视野呈现时,范畴内偏差刺激比范畴间偏差刺激诱发了边缘显著更大的视觉失匹配负波（vMMN）,在右视野呈现时,两类偏差刺激诱发的vMMN无显著差异;范畴内偏差刺激在不同视野呈现时诱发的vMMN无显著差异,范畴间偏差刺激则在右视野呈现时诱发了显著更大的vMMN。这一结果表明,当范畴内和范畴间颜色的辨别难度相同时,语言范畴也会影响早期的、注意前颜色知觉,支持了沃尔夫假说。     

关于幼儿嗅、味、动、触摸感觉道记忆的研究

记忆在幼儿心理的发展过程中,具有极为重要的作用。幼儿知识的掌握,语言的学习,技巧的培养,以至个性的形成,都与记忆活动密切联系。国内外关于幼儿记忆的研究,主要限于有意与无意识记,机械与意义识记,形象与语词记忆等方面,很少从不同感觉道输入信息来进行比较。有的实验虽然涉及到不同感觉道的记忆,但被试者都是7岁以上的儿童,如斯梅德利(Smedley)和三岛、横尾等人的研究。为了全面了解幼儿的记忆发展水平,我们设计了关于幼儿不同感觉道记忆的实验研究,试图通过对幼儿各个感觉道输入信息来全面测查幼儿的视觉、听觉、味觉、嗅觉、动觉和触摸党的记忆水平,了解其发展规律及特点,以便为幼儿记忆的理论研究提供实验数据,为幼儿教育提供心理学依据。     

Differential redundancy gain in onset detection versus offset detection

In a visual simple reaction time paradigm with attention divided between the left and right visual fields, redundancy gain refers to the finding of faster responses to stimuli presented in both fields than to single stimuli. The present study investigated whether the effects of low-level perceptual processing affect the redundancy gain by comparing the detection of onsets versus offsets. In different blocks, participants responded to left and right visual field stimuli that either appeared (onset) or disappeared (offset), with a single stimulus change in some trials and two redundant stimulus changes in others. With onset stimuli, the results replicated previous redundancy gain effects. In contrast, there was much less redundancy gain when participants responded to stimulus offsets. This finding suggests that redundancy gain is sensitive to low-level perceptual characteristics, such as onset versus offset presentation of stimuli.     

Mood-congruent false memories persist over time

There are two contrasting hypotheses that attempt to explain how emotion perception might be organised in the brain. One suggests that all emotions are lateralised to the right hemisphere whereas the other suggests that emotions may be differently lateralised according to valence. Here these two theories are contrasted, in addition to considering the role of emotional intensity in explaining possible differences in strength of lateralisation across emotions. Participants completed a Chimeric Faces Test for each of the six basic emotions: anger, disgust, fear, happiness, sadness and surprise. All emotions showed significant lateralisation to the right hemisphere, however, differences in strength of lateralisation within the right hemisphere were found. Stronger patterns of right hemisphere lateralisation were found for positive emotions and for emotions of higher intensity. The results support the right-hemisphere hypothesis, but suggest that there may be variability in organisation within the right hemisphere across different types of emotion.     

Perception of geometrical arrays tachistoscopically exposed in right and left visual fields.

Geometrical stimuli (48 6-item arrays of familiar forms, e.g., circle), tachistoscopically presented in the right or left visual field, were more accurately perceived in the right than left visual field by 15 college students. Targets about half the length of the displays exposed here were perceived with equal facility in both visual fields (Bryden, 1960). Results suggest that length of array might affect the difference in perceptual accuracy of forms shown in the right and left visual fields. Figures in the right visual field were predominantly processed from left to right, and forms in the left visual field from right to left. Since more symbols were identified in the right than left visual field, the left to right encoding sequence may be more efficient than a right to left movement. Limited experience of most Ss in reading symbols from left to right is probably only one factor. Extensive experience reading alphabetical material from left to right might have developed the physiological mechanism underpinning this sequence more than the one serving the opposite movement.     

The use of contact lenses for the lateralisation of visual input in man.

This research demonstrates the use of a new method of investigating lateralised hemisphere functions. Specially designed contact lenses were used, which directed visual input to either the left or the right cerebral hemisphere. These lenses are an advance on previous methods used in investigating hemisphere function in that they enable the subject to react to stimuli without restrictions on movement and without time limitations on the exposure of stimuli. Investigations of language and visual-spatial functions showed that the lenses appeared to be very effective in lateralising verbal and spatial information.     

知觉加工中存在颜色类别知觉效应的证据

对于颜色的辨别具有类别知觉效应：类间两种颜色的辨别能力比同等颜色空间距离的类内两种颜色的辨别能力更高。对于类别知觉效应的产生机制存在两种观点：知觉特性假设、语言标签假设。以往的研究范式由于实验任务涉及到工作记忆成分,被试在完成任务时会自动地对颜色命名以利于记忆,因此所得证据大多支持语言标签假设,而对知觉特性假设的支持证据则很少。本文利用目标觉察范式最大限度去掉了工作记忆成分,通过测量被试辨别两种颜色的反应时,得到了类别知觉效应。并通过语言干扰任务进一步证实在该实验范式下类别知觉效应与语言的无关性。从而,为知觉特性假设提供了证据     

Asymmetrical perceptual load in lateralised word processing

We applied the Load Theory of attention (Lavie, 1995, 2005) to the case of distraction during processing of lateralised words presented in either the right or the left visual fields. Previous research (Brand-D'Abrescia & Lavie, 2007) showed that lexicality affects selective attention such that the number of letters in a search task only increases perceptual load and reduces irrelevant distractor effects for searches in nonwords but not in words. The present study examined the hypothesis that the effect of lexicality on distractor processing would be stronger for words presented to the left compared to the right hemisphere. The results supported this hypothesis and their implications for attention to words in the two cerebral hemispheres are discussed. We suggest that the efficiency of attentional selection differed because perceptual load in the visual fields taxed processing depending on hemispheric language expertise.     

Influence of auditory and audiovisual stimuli on the right–left prevalence effect

When auditory stimuli are used in two-dimensional spatial compatibility tasks, where the stimulus and response configurations vary along the horizontal and vertical dimensions simultaneously, a right–left prevalence effect occurs in which horizontal compatibility dominates over vertical compatibility. The right–left prevalence effects obtained with auditory stimuli are typically larger than that obtained with visual stimuli even though less attention should be demanded from the horizontal dimension in auditory processing. In the present study, we examined whether auditory or visual dominance occurs when the two-dimensional stimuli are audiovisual, as well as whether there will be cross-modal facilitation of response selection for the horizontal and vertical dimensions. We also examined whether there is an additional benefit of adding a pitch dimension to the auditory stimulus to facilitate vertical coding through use of the spatial-musical association of response codes (SMARC) effect, where pitch is coded in terms of height in space. In Experiment 1, we found a larger right–left prevalence effect for unimodal auditory than visual stimuli. Neutral, non-pitch coded, audiovisual stimuli did not result in cross-modal facilitation, but did show evidence of visual dominance. The right–left prevalence effect was eliminated in the presence of SMARC audiovisual stimuli, but the effect influenced horizontal rather than vertical coding. Experiment 2 showed that the influence of the pitch dimension was not in terms of influencing response selection on a trial-to-trial basis, but in terms of altering the salience of the task environment. Taken together, these findings indicate that in the absence of salient vertical cues, auditory and audiovisual stimuli tend to be coded along the horizontal dimension and vision tends to dominate audition in this two-dimensional spatial stimulus–response task.     

Flank to the left,flank to the right: Testing the modified receptive field hypothesis of letter-specific crowding

The present study tested for effects of number of flankers positioned to the left and to the right of target characters as a function of visual field and stimulus type (letters or shapes). On the basis of the modified receptive field hypothesis (Chanceaux & Grainger, 2012), we predicted that the greatest effects of flanker interference would occur for leftward flankers with letter targets in the left visual field. Target letters and simple shape stimuli were briefly presented and accompanied by either 1, 2, or 3 flankers of the same category either to the left or to the right of the target, and in all conditions with a single flanker on the opposite side. Targets were presented in the left or right visual field at a fixed eccentricity, such that targets and flankers always fell into the same visual field. Results showed greatest interference for leftward flankers associated with letter targets in the left visual field, as predicted by the modified receptive field hypothesis.     

Electrodermal orienting responses to verbal and geometrical visual stimuli projected to the left or right retinal half-fields: sex differences

Using the visual half-field technique, verbal and geometrical slides were repeatedly projected to either the left or right visual field in an electrodermal orienting paradigm. Bilateral skin conductance response-magnitudes were recorded continuously over trials. Half the subjects (8 males and 8 females) had a verbal and a geometrical slide repeatedly presented to the right of a central fixation-point, (i.e. initial left hemisphere input) and the other half had the same kinds of stimuli presented to the left (i.e. initial right hemisphere input). There were 32 presentations of each stimulus, i.e. a total of 64 trials. The intertrial interval (ITI) varied between 25 to 40 sec. Results showed significantly larger response-magnitudes in the female group having the stimuli presented in the left visual field and especially to the geometrical slide. The same trend in data was also found for the male subgroup having the stimuli presented in the left visual field. No significant differences between the bilateral left and right hand recordings were foundin the main analysis. However, a closer inspection of the data indicated the left hand recording to be more sensitive than the right hand recording.     

About hemispheric differences in the processing of temporal intervals

The purpose of the present study was to identify differences between cerebral hemispheres for processing temporal intervals ranging from .9 to 1.4 s. The intervals to be judged were marked by series of brief visual signals located in the left or the right visual field. Series of three (two standards and one comparison) or five intervals (four standards and one comparison), marked by sequences of 4 or 6 signals, were compared. While discrimination, as estimated by d', was significantly better in the 4-standard than in the 2-standard condition when stimuli were presented in the left visual field (LVF), this number-of-standard effect on discrimination varied with the difficulty levels when the signals were presented in the LVF. Moreover, the discrimination levels were constant for the different base durations with stimuli presented in the LVF, but not with stimuli presented in the right visual field. This article discusses the implication of these findings for the study of hemispheric dominance for temporal processing and for a single-clock hypothesis.     

Ratings of emotion in faces are influenced by the visual field to which stimuli are presented

This experiment was designed to assess the differential impact of initially presenting affective information to the left versus right hemisphere on both the perception of and response to the input. Nineteen right-handed subjects were presented with faces expressing happiness and sadness. Each face was presented twice to each visual field for an 8-sec duration. The electro-oculogram (EOG) was monitored and fed back to subjects to train them to keep their eyes focused on the central fixation point as well as to eliminate trials confounded by eye movement artifact. Following each slide presentation, subjects rated the intensity of the emotional expression depicted in the face and their emotional reaction to the face on a series of 7-point rating scales. Subjects reported perceiving more happiness in response to stimuli initially presented to the left hemisphere (right visual field) compared to presentations of the identical faces to the right hemisphere (left visual field). This effect was predominantly a function of ratings on sad faces. A similar, albeit less robust, effect was found on self-ratings of happiness (the degree to which the face elicited the emotion in the viewer). These data challenge the view that the right hemisphere is uniquely involved in all emotional behavior. The implications of these findings for theories concerning the lateralization of emotional behavior are discussed.     

Hemispheric asymmetry in cross-race face recognition

This study examines two phenomena related to face perception, both of which depend on experience and holistic processing: perceivers process faces more efficiently in the right hemisphere of the brain (a hemispheric asymmetry), and they typically show greater recognition accuracy for members of their racial ingroup (a cross-race recognition deficit). The current study tests the possibility that these two effects are related. If asymmetry depends on experience, it should be particularly evident with (more familiar) ingroup faces; if cross-race recognition relies on holistic processing, it should be particularly evident for faces presented to the right hemisphere. Black and White participants viewed Black and White faces presented to either the left or right visual field. As predicted, participants showed a more pronounced asymmetry for ingroup (rather than outgroup) faces, and cross-race recognition deficits were more pronounced for stimuli presented to the left (rather than the right) visual field.