The persistence of attention to emotion: brain potentials during and after picture presentation

Emotional stimuli have been shown to elicit increased perceptual processing and attentional allocation. The late positive potential (LPP) is a sustained P300-like component of the event-related potential that is enhanced after the presentation of pleasant and unpleasant pictures as compared with neutral pictures. In this study, the LPP was measured using dense array electroencephalograph both before and after pleasant, neutral, and unpleasant images to examine the time course of attentional allocation toward emotional stimuli. Results from 17 participants confirmed that the LPP was larger after emotional than neutral images and that this effect persisted for 800 ms after pleasant picture offset and at least 1,000 ms after unpleasant picture offset. The persistence of increased attention after unpleasant compared to pleasant stimuli is consistent with the existence of a negativity bias. Overall, these results indicate that attentional capture of emotion continues well beyond picture presentation and that this can be measured with the LPP. Implications and directions for future research are discussed.     

Emotional state affects the initiation of forward gait

The aim of the current study was to determine the extent to which pleasant and unpleasant emotional states impact the initiation of forward gait. Participants initiated gait and walked for several steps following the presentation of low arousing pleasant, high arousing pleasant, low arousing unpleasant, high arousing unpleasant, and neutral pictures. Reaction time, displacement, and velocity of the center of pressure (COP) trajectory, and length and velocity of the first and second steps were calculated. Exposure to the highly arousing unpleasant pictures reduced reaction times compared to all other affective conditions. Compared to the low arousing unpleasant pictures, exposure to the high and low arousing pleasant pictures increased the displacement of the COP movement during the anticipatory postural adjustment phase of gait initiation. Additionally, exposure to the low arousing pleasant pictures increased the velocity of the COP movement during the anticipatory postural adjustment phase, compared to the high and low arousing unpleasant pictures. Exposure to the high and low arousing pleasant pictures increased the velocity of the first step relative to the low arousing unpleasant pictures. These findings demonstrate that highly arousing unpleasant emotional states accelerate the initial motor response, but pleasant emotional states generally facilitate the initiation of forward gait due to the approach-oriented directional salience of the movement. These findings extend the scope of the motivational direction hypothesis by demonstrating the effects of emotional reactivity on the initiation of gait.     

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.     

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.     

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.     

Modulation of auditory spatial attention by visual emotional cues: differential effects of attentional engagement and disengagement for pleasant and unpleasant cues

Previous research has demonstrated that threatening, compared to neutral pictures, can bias attention towards non-emotional auditory targets. Here we investigated which subcomponents of attention contributed to the influence of emotional visual stimuli on auditory spatial attention. Participants indicated the location of an auditory target, after brief (250 ms) presentation of a spatially non-predictive peripheral visual cue. Responses to targets were faster at the location of the preceding visual cue, compared to at the opposite location (cue validity effect). The cue validity effect was larger for targets following pleasant and unpleasant cues compared to neutral cues, for right-sided targets. For unpleasant cues, the crossmodal cue validity effect was driven by delayed attentional disengagement, and for pleasant cues, it was driven by enhanced engagement. We conclude that both pleasant and unpleasant visual cues influence the distribution of attention across modalities and that the associated attentional mechanisms depend on the valence of the visual cue.     

青年人和老年人加工情绪图片过程中的注意偏向:眼动研究

利用眼动追踪技术,考察了老年人与青年人加工情绪图片过程中的注意偏向及再认成绩。给被试同时呈现积极、中性及消极情绪图片,分为注意和记忆两部分任务。基于线性混合模型的分析发现,与青年人相比,老年人表现出对积极图片更大的注意偏向,且在随后的再认过程中对积极情绪图片的再认正确率更高。结果支持了社会情绪选择理论,说明中国老年人同样存在“积极效应”,情绪加工过程中能够通过选择偏爱的积极情绪信息来适应老化。     

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.     

The effects of anxiety upon attention allocation to affective stimuli

Pictures of emotionally aversive, neutral, and pleasant scenes were presented for 500 ms, followed by a probe presented in the same location (valid trials) or an alternate location (invalid trials) as the picture. Response-times to the probes were recorded in low (N=20) and high (N=27) trait anxious participants. Results revealed an overall negative cue validity effect of shorter reaction times (RTs) on invalid than valid trials, suggestive of an inhibition of return effect. Moreover, high trait anxious females showed a reduced negative cue validity effect for aversive pictures in comparison with neutral and pleasant pictures, suggestive of selective interference by the unpleasant material. By contrast, low trait anxious females showed an enhanced negative cue validity effect for aversive pictures relative to neutral and pleasant pictures, suggestive of attentional avoidance of the aversive content. The emotional content of picture cues did not significantly affect RTs in males, regardless of anxiety status. The results suggest that biased attention processes for aversive stimuli may contribute to the greater female propensity for anxiety disorders.     

When good things go bad: the reflex physiology of defense

For humans, the threat of painful shock greatly potentiates the reflexive startle blink. Moreover, viewing unpleasant, compared with pleasant, pictures also prompts heightened startle reflexes, suggesting that the startle reflex indexes general defensive activation. In this study, pleasant or unpleasant pictures were used to signal shock threat in order to explore how previous affective associations modulate new defensive reactions. When cuing threat of shock, pleasant and unpleasant pictures prompted physiological profiles consistent with defensive activation, indicating that threat of shock renders previously pleasant cues aversive. For unpleasant pictures only, defensive startle was potentiated even when these cues signaled safety. Taken together, the data indicate that (a) regardless of their intrinsic affective meaning, cues signaling shock threat prompt somatic and autonomic reactions consistent with defense, and that (b) intrinsically unpleasant cues continue to prompt defensive activation even when the context of their presentation is specifically non-threatening.     

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.     

Rapid picture presentation and affective engagement

Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement.     

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.     

Identification facilitation for emotionally arousing verbs during the attentional blink

The present study aimed to examine affective modulation of the "attentional blink" effect during rapid serial visual presentation (RSVP). Pleasant, neutral, and unpleasant written verbs were used as a 2nd target (T2) in an 8.6-Hz RSVP paradigm. Pronounced effects of 1st target (T1)-T2 stimulus onset asynchrony (SOA) were found, showing reduced report accuracy for 232- and 464-ms SOAs. Affectively arousing (pleasant and unpleasant) T2s were associated with enhanced accuracy compared with neutral T2s specifically during short (232 ms) SOAs. In contrast, pleasant and unpleasant T2s rated low in terms of emotional arousal did not show this enhancement. These results suggest that affectively arousing information is selected preferentially from a temporal stream, facilitating processes such as working memory consolidation and action.     

Attending to affect: appraisal strategies modulate the electrocortical response to arousing pictures

Arousing (unpleasant and pleasant) pictures elicit increased neurophysiological measures of perceptual processing. In particular, the electrocortical late positive potential (LPP) is enhanced for arousing, compared with neutral, pictures. To determine whether the magnitude of the LPP is sensitive to the way stimuli are appraised, 16 participants viewed both pleasant and unpleasant pictures and categorized them along an affective or nonaffective dimension. Results indicate that the LPP was reduced for both pleasant and unpleasant pictures when participants made nonaffective, compared with affective, judgments. These results are consistent with previous studies that have used functional neuroimaging to investigate the role of appraisal on emotional processing. The results are further discussed in terms of the utility of using the LPP to study emotion regulation.     

Emotion among women with psychopathy during picture perception

Emotional reactions in women with psychopathy were examined in a mixed-picture paradigm using psychophysiological measures. Startle probes were presented at 2.0 or 4.5 s following onset of a 6-s picture presentation. At 2.0 s, nonpsychopaths exhibited the typical pattern of eyeblink reflex magnitude: unpleasant > neutral > pleasant. Psychopaths with high general levels of anxiety also exhibited this pattern. Psychopaths with lower anxiety exhibited attenuated reflex magnitudes during unpleasant pictures. Similarly, when focusing on psychopathy components, only individuals expressing high antisocial behavior and high emotional detachment exhibited smaller reflex magnitudes during unpleasant pictures. At 4.5 s, all groups exhibited normal, potentiated reflex magnitudes during unpleasant pictures. Group differences were not observed for other measures.     

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.     

Sex differences in the time course of emotion

Conventional wisdom holds that women are more "emotional" than men. However, research evidence suggests that sex differences in emotion are considerably more complex. The authors tested hypotheses about sex differences in the engagement of the approach and avoidance motivational systems thought to underpin emotional responses. The authors measured reported emotional experience and startle response magnitude both during the presentation and after the offset of emotional stimuli that engage these motivational systems to assess whether men and women differ in their patterns of immediate response to emotional stimuli and in their patterns of recovery from these responses. Our findings indicated that women were more experientially reactive to negative, but not positive, emotional pictures compared to men, and that women scored higher than men on measure of aversive motivational system sensitivity. Although both men and women exhibited potentiation of the startle response during the presentation of negative pictures relative to neutral pictures, only women continued to show this relative potentiation during the recovery period, indicating that women were continuing to engage the aversive motivational system after the offset of negative emotional pictures.     

Beyond good and evil: the time-course of neural activity elicited by specific picture content

The present study examined electrocortical evidence for a negativity bias, focusing on the impact of specific picture content on a range of event-related potentials (ERPs). To this end, ERPs were recorded while 67 participants viewed a variety of pictures from the International Affective Picture System. Examination of broad categories (i.e., pleasant, neutral, unpleasant) found no evidence for a negativity bias in two early components, the N1 and the Early Posterior Negativity (EPN), but revealed that unpleasant images did elicit a larger late positive potential (LPP) than pleasant pictures. However, images of erotica and mutilation elicited comparable LPP responses, as did affiliative and threatening images. Exciting (i.e., sports) images and disgusting images elicited smaller LPPs than other emotional images, similar to neutral images containing people-which were associated with the largest LPPs among neutral pictures. When these three anomalous categories (exciting, disgusting, and scenes with people) were excluded, unpleasant images no longer elicited a larger LPP than pleasant images. Thus, including exciting images in pleasant ERP averages disproportionately reduces the LPP. The present findings are discussed in light of the motivational significance of specific picture subtypes.     

Emotion affects action: Midcingulate cortex as a pivotal node of interaction between negative emotion and motor signals

Affective pictures drive the activity of brain networks and impact behavior. We showed previously that viewing unpleasant pictures interfered in the performance of a basic nonemotional visual detection task. In the present study, we employed functional magnetic resonance imaging to test the hypothesis that behavioral interference may result from the interaction between negatively valenced and motor-related signals in the brain. As in our previous study (Pereira et al., 2006), participants performed a simple target detection task that followed the presentation of unpleasant or neutral pictures. Our results revealed that an unpleasant emotional context modulated evoked responses in several regions engaged by the simple target detection task. In particular, the midcingulate cortex was recruited when participants performed target detection trials during the unpleasant context, and signal responses in this region closely mirrored the pattern of behavioral interference (as revealed via reaction time). Our findings suggest that the midcingulate cortex may be an important site for the interaction between negatively valenced signals and motor signals in the brain and that it may be involved in the implementation of defensive responses, such as freezing.