An increase in stimulus arousal has differential effects on the processing speed of pleasant and unpleasant stimuli

The arousal value of a stimulus influences its salience, whereby higher arousal should lead to faster processing. However, in previous research, participants consistently made faster valence judgments for low arousal, pleasant stimuli than for high arousal, pleasant stimuli. The speed of valence and arousal judgments for pictures and words were investigated in three experiments. Valence judgments were faster for low arousal than for high arousal pleasant pictures and for high arousal than for low arousal unpleasant pictures and words. Moreover, arousal judgments were faster for low arousal than high arousal pleasant and for high arousal than low arousal unpleasant pictures and words. The current research confirms that the impact of valence and arousal on processing speed does not reflect on the labels (valence versus arousal) used when recording speeded judgments. Similarly to valence, stimulus arousal interacts differentially with the evaluation of pleasant and unpleasant stimuli producing a processing advantage for high arousal, unpleasant stimuli but not high arousal, pleasant stimuli.     

Evaluative ratings and attention across the life span: emotional arousal and gender

This study was designed to investigate the evolution of emotional processing over the whole adult life span as a function of stimulus arousal and participants’ gender. To this end, self-reported affective evaluation and attentional capture prompted by pleasant and unpleasant pictures varying in arousal were measured in a large sample of participants (n?=?211) balanced by gender and equally spread across seven decades from 20 to 90 years. Results showed age differences only for affective evaluation of pleasant stimuli, with opposite patterns depending on stimulus arousal. As age increased, low-arousing pleasant cues (e.g. images of babies) were experienced as more pleasant and arousing by both males and females, whereas high-arousing stimuli (e.g. erotic images) were experienced as less pleasant only by females. In contrast, emotional pictures (both pleasant and unpleasant) were effective at capturing attention in a similar way across participants, regardless of age and gender. Taken together, these findings suggest that specific emotional cues prompt different subjective responses across different age groups, while basic mechanisms involved in attentional engagement towards both pleasant and unpleasant stimuli are preserved in healthy ageing.     

Event-related potentials of emotional memory: encoding pleasant,unpleasant, and neutral pictures

Emotional events tend to be remembered better than nonemotional events. We investigated this phenomenon by measuring two event-related potential (ERP) effects: the emotion effect (more positive ERPs for pleasant or unpleasant stimuli than for neutral stimuli) and the subsequent memory effect (more positive ERPs for subsequently remembered items than for subsequently forgotten items). ERPs were measured while subjects rated the emotional content of pleasant, unpleasant, and neutral pictures. As was expected, subsequent recall was better for pleasant and unpleasant pictures than for neutral pictures. The emotion effect was sensitive to arousal in parietal electrodes and to both arousal and valence in frontocentral electrodes. The subsequent memory effect at centroparietal electrodes was greater for emotional pictures than for neutral pictures during an early epoch (400-600 msec). This result suggests that emotional information has privileged access to processing resources, possibly leading to better memory formation.     

Vivid: How valence and arousal influence word processing under different task demands

In this study, we used event-related potentials to examine how different dimensions of emotion—valence and arousal—influence different stages of word processing under different task demands. In two experiments, two groups of participants viewed the same single emotional and neutral words while carrying out different tasks. In both experiments, valence (pleasant, unpleasant, and neutral) was fully crossed with arousal (high and low). We found that the task made a substantial contribution to how valence and arousal modulated the late positive complex (LPC), which is thought to reflect sustained evaluative processing (particularly of emotional stimuli). When participants performed a semantic categorization task in which emotion was not directly relevant to task performance, the LPC showed a larger amplitude for high-arousal than for low-arousal words, but no effect of valence. In contrast, when participants performed an overt valence categorization task, the LPC showed a large effect of valence (with unpleasant words eliciting the largest positivity), but no effect of arousal. These data show not only that valence and arousal act independently to influence word processing, but that their relative contributions to prolonged evaluative neural processes are strongly influenced by the situational demands (and by individual differences, as revealed in a subsequent analysis of subjective judgments).     

Affective priming with pictures of emotional scenes: the role of perceptual similarity and category relatedness

Prime pictures portraying pleasant or unpleasant scenes were briefly presented (150-ms display; SOAs of 300 or 800 ms), followed by probe pictures either congruent or incongruent in emotional valence. In an evaluative decision task, participants responded whether the probe was emotionally positive or negative. Affective priming was reflected in shorter response latencies for congruent than for incongruent prime-probe pairs. Although this effect was enhanced by perceptual similarity between the prime and the probe, it also occurred for probes that were physically different, and the effect generalized across semantic categories (animals vs. people). It is concluded that affective priming is a genuine phenomenon, in that it occurs as a function of stimulus emotional content, in the absence of both perceptual similarity and semantic category relatedness between the prime and the probe.     

Social stimuli increase physiological reactivity but not defensive responses

Emotional reactions are crucial in survival because they provide approach and withdrawal behaviors. However, an unsolved question is whether the social content of the affective stimuli has a specific effect on emotional responses. We studied whether the social content of affective pictures influenced the defensive response and response mobilization. For this purpose, we recorded startle blink reflex (a defensive response) and skin conductance responses (a measure of unspecific physiological reactivity or arousal) in 73 participants while they viewed a series of 81 pictures of varying affective valence and social content. Our results revealed that defense response, as indicated by increases in the magnitude of the startle blink reflex, was mainly dependent on threatening or unpleasant cues, but was unrelated to the social content of the pictures. The social content, however, had an influence on pleasant stimuli, provoking an increase in resource mobilization, as reflected by changes in electrodermal activity. Hence, the social content of the affective stimuli may increase the physiological arousal elicited by pleasant stimuli, and it appears to be unrelated to the defense reactivity provoked by unpleasant stimuli.     

Responding to emotional scenes: effects of response outcome and picture repetition on reaction times and the late positive potential

Processing the motivational relevance of a visual scene and reacting accordingly is crucial for survival. Previous work suggests the emotional content of naturalistic scenes affects response speed, such that unpleasant content slows responses whereas pleasant content accelerates responses. It is unclear whether these effects reflect motor-cognitive processes, such as attentional orienting, or vary with the function/outcome of the motor response itself. Four experiments manipulated participants’ ability to terminate the picture (offset control) and, thereby, the response’s function and motivational value. Attentive orienting was manipulated via picture repetition, which diminishes orienting. A total of N?=?81 participants completed versions of a go/no-go task, discriminating between distorted versus intact pictures drawn from six content categories varying in positive, negative, or neutral valence. While all participants responded faster with repetition, only participants without offset control exhibited slower responses to unpleasant and accelerated responses to pleasant content. Emotional engagement, measured by the late positive potential, was not modulated by attentional orienting (repetition), suggesting that the interaction between repetition and offset control is not due to altered emotional engagement. Together, results suggest that response time changes as a function of emotional content and sensitivity to attention orienting depends on the motivational function of the motor response.     

Early modulation of visual perception by emotional arousal: Evidence from steady-state visual evoked brain potentials

Allocation of processing resources to emotional picture stimuli was examined using steady-state visual evoked brain potentials (ssVEPs). Participants viewed a set of 60 colored affective pictures from the International Affective Picture System, presented in a flickering mode at 10 Hz in order to elicit ssVEPs. Phase and amplitude of the 10-Hz ssVEP were examined for six picture categories: threat and mutilation (unpleasant), families and erotica (pleasant), and household objects and persons (neutral). Self-reported affective arousal and hedonic valence of the picture stimuli were assessed by means of subjective ratings. Viewing affectively arousing (unpleasant and pleasant) pictures was associated with enhanced ssVEP amplitude at parieto-occipital recording sites, as compared with neutral stimuli. Phase information suggested increased coactivation of right occipitotemporal and frontotemporal sources during processing of affectively arousing stimuli. These findings are consistent with reentrant modulation of early visual processing by distributed networks including subcortical and neocortical structures according to a stimulus's motivational relevance.     

Psychophysiological responses to sport-specific affective pictures: A study of morality and emotion in athletes

ObjectivesThe link between morality and emotion has received little attention in the sport context. To address this issue, we examined whether moral disengagement, empathy, antisocial behaviour and psychopathy were associated with emotional reactions to unpleasant pictures depicting players being hurt or deliberately fouled in a sport context.DesignA cross-sectional design was employed.MethodTeam sport athletes (N = 66) completed measures of moral disengagement, empathy, antisocial behaviour and psychopathy and then viewed unpleasant, neutral, and pleasant sport pictures while emotional reactions to the pictures were assessed using valence and arousal ratings of the pictures as well as electrocutaneous startle blink, heart rate, skin conductance, and evoked potentials.ResultsMoral disengagement, empathy and psychopathy, but not antisocial behaviour, were associated with emotional reactions to the unpleasant pictures. Specifically, moral disengagement was related to attenuated startle blink responses and higher valence (less unpleasant) ratings, whereas empathy was associated with lower valence (more unpleasant) ratings. Psychopathy was associated with smaller startle blink responses and less heart rate deceleration.ConclusionOur findings provide support for the link between morality and emotion in athletes. Moral variables may be more closely linked with specific measures of emotion, highlighting the utility of taking a multi-measure approach in the assessment of emotion.     

The impact of changes in spatial distance on emotional responses

Drawing on motivational approaches to emotion, the authors propose that the perceived change in spatial distance to pictures that arouse negative emotions exerts an influence on the significance of these pictures. Two experiments induced the illusion that affective pictures approach toward the observer, recede from the observer, or remain static. To determine the motivational significance of the pictures, emotional valence and arousal ratings as well as startle responses were assessed. Approaching unpleasant pictures were found to exert an influence on both the valence and the arousal elicited by the pictures. Furthermore, movement of pleasant or neutral pictures did not influence startle responses, while the second experiment showed that approaching unpleasant pictures elicited enhanced startle responses compared to receding unpleasant pictures. These findings support the view that a change of spatial distance influences motivational significance and thereby shapes emotional responses.     

Negation as a means for emotion regulation? Startle reflex modulation during processing of negated emotional words

This study investigated startle reflex modulation in 33 healthy student participants during the processing of negated emotional items. To build upon previous research, our particular interest was to find out whether processing of negated emotional items modulates emotional responding in line with the logical meaning of the negated expression, or instead leads to paradox emotional effects that point in the direction opposite the one logically implied by the negation. Startle reflex modulation was assessed during silent reading of pleasant and unpleasant nouns. The nouns were either paired with the possessive pronoun my or with the negation word no. The startle eyeblink amplitude was enhanced during processing of the unpleasant pronoun–noun phrases and attenuated during processing of the pleasant phrases. Negation attenuated the startle eyeblink for negated unpleasant nouns and enhanced it for negated pleasant nouns. In line with this finding, negation decreased arousal ratings for unpleasant nouns and reversed the valence ratings for pleasant nouns. Our results are the first to show an effect of negation on both peripheral physiological and subjective indices of affective responding. Our results suggest that negation may be an effective strategy for spontaneous down-regulation of emotional responses to unpleasant, but not to pleasant, stimuli.     

Catechol-O-methyltransferase Val158Met genotype affects neural correlates of aversive stimuli processing

It was previously shown that variation of the catechol-O-methyltransferase (COMT) gene modulates brain activity during the processing of stimuli with negative valence, but not for pleasant stimuli. Here, we tested whether the COMT genotype also modulates the electrophysiological correlates of emotional processing and explored whether the environmental factor of life stress influences this effect. Using the early posterior negativity (EPN) paradigm, event-related brain potentials were measured in 81 healthy individuals during the processing of pictures that evoked emotions of positive and negative valence. As was hypothesized, the COMT genotype affected the EPN amplitudes for unpleasant stimuli, but not for pleasant ones. Specifically, Met/Met carriers respond more sensitively to unpleasant stimuli, as compared with Val/Val carriers. We did not find evidence that life stress moderates the effect of the COMT genotype on emotional stimuli processing.     

Attentional Resources Measured by Reaction Times Highlight Differences Within Pleasant and Unpleasant,High Arousing Stimuli

Simple reaction times (RTs) to acoustic tones were recorded during picture viewing in order to investigate attentional resource allocation to threat stimuli compared with pleasant (sport/adventure) and neutral (household objects) contents. Stimuli were selected as equally arousing according to standardized subjective ratings. In the late stage of picture processing threat pictures showed shorter RTs compared with neutral and pleasant ones. In a second study, a choice-RT task was employed, and a wider range of both pleasant and unpleasant contents was shown. Results indicated slower RTs when blood/injury and erotic couples were presented, compared with other threat, and with other positive (sport/adventure) scenes. Specifically, erotic couples require a greater amount of attentional resources compared with sport/adventure; the same is true for blood/injury stimuli as compared with threat. Remarkable differences were thus shown in attentional deployment to specific stimulus contents within the same valence category. These differences should be taken into account when using such stimuli to investigate emotional processing.     

Affective priming of emotional pictures in parafoveal vision: Left visual field advantage

This study investigated whether stimulus affective content can be extracted from visual scenes when these appear in parafoveal locations of the visual field and are foveally masked, and whether there is lateralization involved. Parafoveal prime pleasant or unpleasant scenes were presented for 150 msec 2.5° away from fixation and were followed by a foveal probe scene that was either congruent or incongruent in emotional valence with the prime. Participants responded whether the probe was emotionally positive or negative. Affective priming was demonstrated by shorter response latencies for congruent than for incongruent prime-probe pairs. This effect occurred when the prime was presented in the left visual field at a 300-msec prime-probe stimulus onset asynchrony, even when the prime and the probe were different in physical appearance and semantic category. This result reveals that the affective significance of emotional stimuli can be assessed early through covert attention mechanisms, in the absence of overt eye fixations on the stimuli, and suggests that right-hemisphere dominance is involved.     

Fearfulness and Affective Evaluations of Pictures

Subjects high and low in temperamental fearfulness made a speeded decision regarding whether each of a series of affective pictures was unpleasant or pleasant. Fearful subjects made faster decisions on unpleasant pictures than did low fear subjects, whereas no difference was found between low and high fear participants when processing pleasant materials. Reaction time differences as a function of fearfulness were amplified when unpleasant pictures were also high in arousal, suggesting that stimulus intensity is a relevant methodological factor when assessing effects of temperament in cognitive processing. Taken together, these data are consistent with the hypothesis that an anxious or fearful temperament is associated with rapid reactions to unpleasant events.     

Age differences in emotional reactions: arousal and age-relevance count

Recent findings suggest positivity effects in older adults' attention and memory, but few studies have examined such effects on the level of emotional reactivity. In this study, 52 young and 52 older adults rated 172 pictures of the International Affective Picture System, differing in arousal and age-relevance, in terms of valence and discrete emotions. Age differences in the ratio of pleasantness reactions to pleasant pictures vs. unpleasantness reactions to unpleasant pictures as well as age differences in absolute levels of unpleasantness and pleasantness reactions suggest that positivity effects in older adults' subjective emotional reactions are reduced under high arousal. There is also evidence that positivity effects may be restricted to stimuli with low relevance in old age.     

Gaze Patterns When Looking at Emotional Pictures: Motivationally Biased Attention

Pictures of either emotionally neutral, pleasant (affectionate), or unpleasant (threat and injury) scenes were paired with nonemotional control pictures and presented for 3 s, while eye fixations were monitored. Preferential attention to the emotional picture of eah pair occurred at an early processing stage: The probability of placement of the first fixation and the proportion of viewing time during the first 500 ms were higher for both pleasant and unpleasant pictures than for neutral pictures, whereas later fixation location and time were not differentially affected. This suggests that, when emotional and nonemotional stimuli are presented simultaneously, emotional meaning captures initial overt orienting and engages attention early, as measured by gaze direction and duration. The possibility that this effect could be accounted for by perceptual differences—such as luminance and complexity—between emotional and neutral pictures was ruled out.     

Emotional Responses to Pictures of Oneself in Healthy College Age Females

Emotional responses related to self-perceptions were investigated in healthy college-aged females using a picture-viewing paradigm that consisted of four categories of pictures (pleasant, neutral, unpleasant, and full body pictures of themselves). The startle eye-blink reflex, facial EMG, and self-reported valence, arousal, and dominance measures were recorded for each picture. Startle reflex and facial EMG measures exhibited decreased activation for self-pictures compared to the other affective categories. Self-reports indicated self-pictures were rated as moderately pleasant, low arousing, and moderately dominant relative to the other affective picture categories. The findings of reduced startle blink reflex coupled with decreased activation for all facial EMG measures and the moderate self-report ratings suggest increased attentional processing for self-pictures. These findings provide an understanding of emotional responses to self-perceptions in healthy young females.     

Eye movement assessment of selective attentional capture by emotional pictures

The eye-tracking method was used to assess attentional orienting to and engagement on emotional visual scenes. In Experiment 1, unpleasant, neutral, or pleasant target pictures were presented simultaneously with neutral control pictures in peripheral vision under instruction to compare pleasantness of the pictures. The probability of first fixating an emotional picture, and the frequency of subsequent fixations, were greater than those for neutral pictures. In Experiment 2, participants were instructed to avoid looking at the emotional pictures, but these were still more likely to be fixated first and gazed longer during the first-pass viewing than neutral pictures. Low-level visual features cannot explain the results. It is concluded that overt visual attention is captured by both unpleasant and pleasant emotional content.     

Reappraisal modulates the electrocortical response to unpleasant pictures

Cognitive strategies such as reappraisal reduce the intensity of negative experience and brain activity that is sensitive to emotional salience. The time course of reappraisal-related neural modulation remains unclear, and it is unknown whether the electrocortical response to emotional stimuli is sensitive to reappraisal. Event-related brain potentials were recorded first while participants passively viewed pleasant, unpleasant, and neutral pictures, and then during an emotion regulation block in which participants were instructed to attend to or reappraise unpleasant pictures. The late positive potential (LPP) was enhanced for pleasant and unpleasant pictures in the passive viewing block, and reappraisal resulted in a reliably reduced LPP—a protracted modulation that began 200 msec after stimulus onset. The degree of LPP modulation was positively related to reductions in the self-reported emotional intensity that followed emotion regulation instructions. These results indicate that reappraisal modulates early electrocortical activity that is related to emotional salience, and that the LPP is a useful tool for studying emotion regulation.