► Integration of recent electrophysiological (ERP) and hemodynamic neuroimaging (fMRI) studies. ► Emotional valence and arousal affect early stages of word recognition. ► Emotional valence recruits ...higher-order, evaluative processes. ► Arousal recruits more automatic, perceptual and physiological processes. ► Discussion of theoretical and methodological issues as well as future directions.
A growing body of literature investigating the neural correlates of emotion word processing has emerged in recent years. Written words have been shown to represent a suitable means to study emotion processing and most importantly to address the distinct and interactive contributions of the two dimensions of emotion: valence and arousal. The aim of the present review is to integrate findings from electrophysiological (ERP) and hemodynamic neuroimaging (fMRI) studies in order to provide a better understanding of emotion word processing. It provides an up-to-date review of recent ERP studies since the review by Kissler et al. (2006) as well as the first review of hemodynamic brain imaging studies in the field. A discussion of theoretical and methodological issues is also presented, along with suggestions for future research.
Why do people so often use metaphorical expressions when literal paraphrases are readily available? This study focuses on a comparison of metaphorical statements involving the source domain of taste ...(e.g., “She looked at him sweetly”) and their literal paraphrases (e.g., “She looked at him kindly”). Metaphorical and literal sentences differed only in one word and were normed for length, familiarity, imageability, emotional valence, and arousal. Our findings indicate that conventional metaphorical expressions are more emotionally evocative than literal expressions, as the amygdala and the anterior portion of the hippocampus were more active in the metaphorical sentences. They also support the idea that even conventional metaphors can be grounded in sensorimotor and perceptual representations in that primary and secondary gustatory areas (lateral OFC, frontal operculum, anterior insula) were more active as well. A comparison of the individual words that distinguished the metaphorical and literal sentences revealed greater activation in the lateral OFC and the frontal operculum for the taste-related words, supporting the claim that these areas are relevant to taste.
Figurative expressions have been shown to play a special role in evoking affective responses, as compared to their literal counterparts. This study provides the first database of conceptual metaphors ...that includes ratings of affective properties beyond psycholinguistic properties. To allow for the investigation of natural reading processes, 64 natural stories were created, half of which contained two or three conceptual metaphors that relied on the same mapping, whereas the other half contained the metaphors’ literal counterparts. To allow for tighter control and manipulation of the different properties, 120 isolated sentences were also created, half of which contained one metaphorical word, which was replaced by its literal rendering in the other half. All stimuli were rated for emotional valence, arousal, imageability, and metaphoricity, and the pairs of metaphorical and literal stimuli were rated for their similarity in meaning. A measure of complexity was determined and computed. The stories were also rated for naturalness and understandability, and the sentences for familiarity. Differences between the metaphorical and literal stimuli and relationships between the affective and psycholinguistic variables were explored and are discussed in light of extant empirical research. In a nutshell, the metaphorical stimuli were rated as being higher in emotional arousal and easier to imagine than their literal counterparts, thus confirming a role of metaphor in evoking emotion and in activating sensorimotor representations. Affective variables showed the typical U-shaped relationship consistently found in word databases, whereby increasingly positive and negative valence is associated with higher arousal. Finally, interesting differences between the stories and sentences were observed.
A growing body of literature shows that the emotional content of verbal material affects reading, wherein emotional words are given processing priority compared to neutral words. Human emotions can ...be conceptualised within a two-dimensional model comprised of emotional valence and arousal (intensity). These variables are at least in part distinct, but recent studies report interactive effects during implicit emotion processing and relate these to stimulus-evoked approach-withdrawal tendencies.
The aim of the present study was to explore how valence and arousal interact at the neural level, during implicit emotion word processing. The emotional attributes of written word stimuli were orthogonally manipulated based on behavioural ratings from a corpus of emotion words. Stimuli were presented during an fMRI experiment while 16 participants performed a lexical decision task, which did not require explicit evaluation of a word′s emotional content.
Results showed greater neural activation within right insular cortex in response to stimuli evoking conflicting approach-withdrawal tendencies (i.e., positive high-arousal and negative low-arousal words) compared to stimuli evoking congruent approach vs. withdrawal tendencies (i.e., positive low-arousal and negative high-arousal words). Further, a significant cluster of activation in the left extra-striate cortex was found in response to emotional than neutral words, suggesting enhanced perceptual processing of emotionally salient stimuli.
These findings support an interactive two-dimensional approach to the study of emotion word recognition and suggest that the integration of valence and arousal dimensions recruits a brain region associated with interoception, emotional awareness and sympathetic functions.
•Emotional valence and arousal affect reading interactively.•Positive high-arousal and negative low-arousal words evoke conflicting reactions.•Enhanced right insula activation was found in response to conflicting stimuli.•Insula integrates viscero-sensory and cognitive/evaluative information.•Enhanced extra-striate cortex activation was found for emotional than neutral words.
Despite flourishing research on the relationship between emotion and literal language, and despite the pervasiveness of figurative expressions in communication, the role of figurative language in ...conveying affect has been underinvestigated. This study provides affective and psycholinguistic norms for 619 German idiomatic expressions and explores the relationships between affective and psycholinguistic idiom properties. German native speakers rated each idiom for emotional valence, arousal, familiarity, semantic transparency, figurativeness, and concreteness. They also described the figurative meaning of each idiom and rated how confident they were about the attributed meaning. The results showed that idioms rated high in valence were also rated high in arousal. Negative idioms were rated as more arousing than positive ones, in line with results from single words. Furthermore, arousal correlated positively with figurativeness (supporting the idea that figurative expressions are more emotionally engaging than literal expressions) and with concreteness and semantic transparency. This suggests that idioms may convey a more direct reference to sensory representations, mediated by the meanings of their constituting words. Arousal correlated positively with familiarity. In addition, positive idioms were rated as more familiar than negative idioms. Finally, idioms without a literal counterpart were rated as more emotionally valenced and arousing than idioms with a literal counterpart. Although the meanings of ambiguous idioms were less correctly defined than those of unambiguous idioms, ambiguous idioms were rated as more concrete than unambiguous ones. We also discuss the relationships between the various psycholinguistic variables characterizing idioms, with reference to the literature on idiom structure and processing.
► Emotionally valenced words are given processing priority compared to neutral words. ► This priority is reflected in behavioural as well as ERP measures. ► A trend towards a significant interaction ...of valence and arousal was found. ► The trend towards an interaction appears at early, implicit processing stages. ► Apparently, arousal modulates valence differently in positive and negative words.
Models of affect assume a two-dimensional framework, composed of emotional valence and arousal. Although neuroimaging evidence supports a neuro-functional distinction of their effects during single word processing, electrophysiological studies have not yet compared the effects of arousal within the same category of valence (positive and negative). Here we investigate effects of arousal and valence on written lexical decision. Amplitude differences between emotion and neutral words were seen in the early posterior negativity (EPN), the late positive complex and in a sustained slow positivity. In addition, trends towards interactive effects of valence and arousal were observed in the EPN, showing larger amplitude for positive, high-arousal and negative, low-arousal words. The results provide initial evidence for interactions between arousal and valence during processing of positive words and highlight the importance of both variables in studies of emotional stimulus processing.
The present study aims to investigate the neural correlates of processing conventional figurative language in non-native speakers in a comparison with native speakers. Italian proficient L2 learners ...of German and German native speakers read conventional metaphorical statements as well as literal paraphrases that were comparable on a range of psycholinguistic variables. Results confirm previous findings that native speakers show increased activity for metaphorical processing, and left amygdala activation increases with increasing Metaphoricity. At the whole-brain level, L2 learners showed the expected overall differences in activation when compared to native speakers (in the fronto-temporal network). But L2 speakers did not show any distinctive activation outside the caudate nucleus as Metaphoricity increased, suggesting that the L2 speakers were less affected by increasing Metaphoricity than native speakers were. With small volume correction, only a single peak in the amygdala reached threshold for L2 speakers as Metaphoricity increased. The findings are consistent with the view that metaphorical language is more engaging for native speakers but not necessarily for L2 speakers.
•Conventional metaphors engage native speakers at the emotional level.•Even if (almost) devoid of emotive content.•L2 speakers process conventional metaphors and their counterparts similarly.•Activating extended-language and switching networks for both (than native speakers).•L2 speakers show no activation except in caudate nucleus as metaphoricity increases.
Conventional metaphorical sentences such as She's asweetchild have been found to elicit greater amygdala activation than matched literal sentences (e.g., She's akindchild). In the present fMRI study, ...this finding is strengthened and extended with naturalistic stimuli involving longer passages and a range of conventional metaphors. In particular, a greater number of activation peaks (four) were found in the bilateral amygdala when passages containing conventional metaphors were read than when their matched literal versions were read (a single peak); while the direct contrast between metaphorical and literal passages did not show significant amygdala activation, parametric analysis revealed that BOLD signal changes in the left amygdala correlated with an increase in metaphoricity ratings across all stories. Moreover, while a measure of complexity was positively correlated with an increase in activation of a broad bilateral network mainly involving the temporal lobes, complexity was not predictive of amygdala activity. Thus, the results suggest that amygdala activation is not simply a result of stronger overall activity related to language comprehension, but is more specific to the processing of metaphorical language.
This work is the first to show that conventional metaphorical language in naturalistic longer passages that includes a range of metaphors elicits more activation in the amygdala–an area recognized to be involved in emotional processing–than carefully matched literal control passages. We probe this finding with parametric analyses using a measure of syntactic complexity and subjective judgments of metaphoricity. While complexity correlates with more overall bilateral activation of the temporal lobes, it does not correlate with amygdala activation. Instead, amygdala activation correlates with metaphoricity, suggesting that the increase in emotional salience is specific to metaphoricity and is not simply a result of an overall increase in brain activity in regions associated with language comprehension.
•Passages with metaphors are more emotionally engaging than literal passages.•The amygdala showed more enhanced activation for metaphorical stories.•Increase in metaphoricity and story complexity engaged language-relevant networks.•However, only increase in metaphoricity activated the amygdala.•These results strengthen and generalize previous ones to more natural reading.
•We investigated the emotion-inducing potential of single words when reading texts.•Affective word (i.e., lexical) ratings correlated with whole text ratings.•Emotional valence of words significantly ...modulated activity in the left amygdala.•Arousal range of constituting words modulated activity in left amygdala and insula.•Results suggest that a text’s constituting words can predict its emotion potential.
Previous studies suggested that the emotional connotation of single words automatically recruits attention. We investigated the potential of words to induce emotional engagement when reading texts. In an fMRI experiment, we presented 120 text passages from the Harry Potter book series. Results showed significant correlations between affective word (lexical) ratings and passage ratings. Furthermore, affective lexical ratings correlated with activity in regions associated with emotion, situation model building, multi-modal semantic integration, and Theory of Mind. We distinguished differential influences of affective lexical, inter-lexical, and supra-lexical variables: differential effects of lexical valence were significant in the left amygdala, while effects of arousal-span (the dynamic range of arousal across a passage) were significant in the left amygdala and insula. However, we found no differential effect of passage ratings in emotion-associated regions. Our results support the hypothesis that the emotion potential of short texts can be predicted by lexical and inter-lexical affective variables.
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