The relationship between induced emotional arousal and amnesia

An experiment was conducted to test a hypothesis emanating from a similarity in data pattern between studies on amnesia and studies on the effects of arousal on memory. The hypothesis was that arousal and amnesia might be related, or more precisely, that amnesia induced in the laboratory might be mediated by high levels of arousal. Subjects in this experiment were presented with a thematic, short story in pictorial form. One version of the story consisted of a traumatic, arousal-inducing event placed between neutral events. A second version of the story contained the same neutral events in the beginning and the end, but also a neutral event in the middle. Palmar skin conductance, heart rate, and subjective self-ratings were used to determine that the manipulation made had caused different degrees of emotional arousal for the two groups of subjects presented with the different versions of the story. The methods used to determine memory performance were recall and recognition. The data obtained indicate that amnesia induced in the laboratory is mediated by emotional arousal in terms of concepts of attention and reconstruction.     

The effects of observation on emotional arousal and affiliation

This study assessed the influence of anticipated experimenter surveillance during the performance of a painful or potentially embarrassing act on affiliative preferences before engaging in that act. As predicted, there was an overall preference for isolation when the act to be performed was embarrassing, and this tendency increased with anticipated surveillance. There was an overall preference for affiliation under fear arousal, and this preference also increased with anticipated surveillance. Contrary to previous research, whether or not the potential affiliate was a subject in the experiment (i.e., in a similar or dissimilar emotional state) did not affect these tendencies. Possible ways of accounting for these findings are discussed.     

Norepinephrine-mediated emotional arousal facilitates subsequent pattern separation

Pattern separation, the process by which similar experiences can be stored as distinct memories, has been ascribed to the dentate gyrus (DG) of the hippocampus. The DG is the target of noradrenergic modulation directly and indirectly via the basolateral amygdala. We tested the hypothesis that noradrenergic activation (tested using salivary alpha-amylase) potentiates DG function, enhancing pattern separation, by showing participants fearful stimuli in a pre-training task and then testing their capacity for pattern separation in a later test. Consistent with our hypothesis, we found that increased levels of salivary alpha-amylase were positively correlated with enhanced pattern separation performance even after accounting for general enhancements in recognition.     

Time-limited effects of emotional arousal on item and source memory

Two experiments investigated the time-limited effects of emotional arousal on consolidation of item and source memory. In Experiment 1, participants memorized words (items) and the corresponding speakers (sources) and then took an immediate free recall test. Then they watched a neutral, positive, or negative video 5, 35, or 50?min after learning, and 24 hours later they took surprise memory tests. Experiment 2 was similar to Experiment 1 except that (a) a reality monitoring task was used; (b) elicitation delays of 5, 30, and 45?min were used; and (c) delayed memory tests were given 60?min after learning. Both experiments showed that, regardless of elicitation delay, emotional arousal did not enhance item recall memory. Second, both experiments showed that negative arousal enhanced delayed item recognition memory only at the medium elicitation delay, but not in the shorter or longer delays. Positive arousal enhanced performance only in Experiment 1. Third, regardless of elicitation delay, emotional arousal had little effect on source memory. These findings have implications for theories of emotion and memory, suggesting that emotion effects are contingent upon the nature of the memory task and elicitation delay.     

Spatial distancing reduces emotional arousal to reactivated memories

Psychonomic Bulletin & Review - Memories are able to update and adapt with new information about the world after they are reactivated. However, it is unknown whether the labile period following...     

Processing emotional pictures and words: Effects of valence and arousal

There is considerable debate regarding the extent to which limbic regions respond differentially to items with different valences (positive or negative) or to different stimulus types (pictures or words). In the present event-related fMRI study, 21 participants viewed words and pictures that were neutral, negative, or positive. Negative and positive items were equated on arousal. The participants rated each item for whether it depicted or described something animate or inanimate or something common or uncommon. For both pictures and words, the amygdala, dorsomedial prefrontal cortex (PFC), and ventromedial PFC responded equally to all high-arousal items, regardless of valence. Laterality effects in the amygdala were based on the stimulus type (word 5 left, picture 5 bilateral). Valence effects were most apparent when the individuals processed pictures, and the results revealed a lateral/medial distinction within the PFC: The lateral PFC responded differentially to negative items, whereas the medial PFC was more engaged during the processing of positive pictures.     

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.     

Both predator and prey: emotional arousal in threat and reward

This research examined the psychophysiology of emotional arousal anticipatory to potentially aversive and highly pleasant outcomes. Human brain reactions (event-related potentials) and body reactions (heart rate, skin conductance, the probe startle reflex) were assessed along motivational gradients determined by apparent distance from sites of potential punishment or reward. A predator-prey survival context was simulated using cues that signaled possible money rewards or possible losses; the cues appeared to loom progressively closer to the viewer, until a final step when a rapid key response could ensure reward or avoid a punishing loss. The observed anticipatory response patterns of heightened vigilance and physiological mobilization are consistent with the view that the physiology of emotion is founded on action dispositions that evolved in mammals to facilitate survival by dealing with threats or capturing life-sustaining rewards.     

Effects of nonverbal dissimulation on emotional experience and autonomic arousal.

Three studies are reported that examine the relationship between the nonverbal display of emotional affect and indices of the emotional state. Subjects were asked either to conceal or to exaggerate the facial display associated with the anticipation and reception of painful shocks that varied in intensity. Both self-reports of shock painfulness and skin conductance measures of emotional response showed significant changes paralleling the changes induced in expressive behavior; that is, the suppression of expressive responses decreased the magnitude of phasic skin conductance changes and subjective reports of painfulness as compared to the free expression or exaggeration of pain-related expressive response. The effects were obtained for shocks of varying intensities and for both male and female subjects. The findings support theories of emotion that assume that expressive responses serve a self-regulatory as well as a social-communicative function, and further suggest that the self-regulation is mediated neurally, rather than via a process of self-attribution. Finally, the results highlight the need for research on dissimulation in social interaction to consider the effects of acting upon the actor, as well as its effects upon the inferences of observers.     

Non-monotonic relationships between emotional arousal and memory for color and location

Recent research points to the decreased diagnostic value of subjective retrieval experience for memory accuracy for emotional stimuli. While for neutral stimuli rich recollective experiences are associated with better context memory than merely familiar memories this association appears questionable for emotional stimuli. The present research tested the implicit assumption that the effect of emotional arousal on memory is monotonic, that is, steadily increasing (or decreasing) with increasing arousal. In two experiments emotional arousal was manipulated in three steps using emotional pictures and subjective retrieval experience as well as context memory were assessed. The results show an inverted U-shape relationship between arousal and recognition memory but for context memory and retrieval experience the relationship was more complex. For frame colour, context memory decreased linearly while for spatial location it followed the inverted U-shape function. The complex, non-monotonic relationships between arousal and memory are discussed as possible explanations for earlier divergent findings.     

Congruent bodily arousal promotes the constructive recognition of emotional words

Considerable research has shown that bodily states shape affect and cognition. Here, we examined whether transient states of bodily arousal influence the categorization speed of high arousal, low arousal, and neutral words. Participants realized two blocks of a constructive recognition task, once after a cycling session (increased arousal), and once after a relaxation session (reduced arousal). Results revealed overall faster response times for high arousal compared to low arousal words, and for positive compared to negative words. Importantly, low arousal words were categorized significantly faster after the relaxation than after the cycling, suggesting that a decrease in bodily arousal promotes the recognition of stimuli matching one’s current arousal state. These findings highlight the importance of the arousal dimension in emotional processing, and suggest the presence of arousal-congruency effects.     

Attention and the processing of emotional words: Dissociating effects of arousal

There is debate as to whether emotionally charged words receive preferential attentional processing in normal individuals. Using a digit-parity task, Harris and Pashler (2004) found that threat-related words captured attention on only the first trial, suggesting no attention capture for emotional words aside from an initial surprise reaction. We examined whether sexually explicit words would be more effective at capturing attention in a similar task. Our results with threat words replicated those of Harris and Pashler in that threat words did not lead to an increase in reaction time (RT) on the parity task, relative to emotionally neutral words. However, sexual words led to a marked increase in RTs for over 100 trials. Words’ arousal ratings, but not their valence ratings, predicted the amount of interference. Parity RTs for individual words were also related to memory for the word on a surprise memory test. Sexually explicit words may have more potential to capture attention than do threat-related words. The words presented here as distractors in the digit-parity task, along with their corresponding valence ratings, arousal ratings, and digit-parity RTs, can be downloaded from www.psychonomic.org/archive.     

Developmental reversals in false memory: Effects of emotional valence and arousal

Do the emotional valence and arousal of events distort children’s memories? Do valence and arousal modulate counterintuitive age increases in false memory? We investigated those questions in children, adolescents, and adults using the Cornell/Cortland Emotion Lists, a word list pool that induces false memories and in which valence and arousal can be manipulated factorially. False memories increased with age for unpresented semantic associates of word lists, and net accuracy (the ratio of true memory to total memory) decreased with age. These surprising developmental trends were more pronounced for negatively valenced materials than for positively valenced materials, they were more pronounced for high-arousal materials than for low-arousal materials, and developmental increases in the effects of arousal were small in comparison with developmental increases in the effects of valence. These findings have ramifications for legal applications of false memory research; materials that share the emotional hallmark of crimes (events that are negatively valenced and arousing) produced the largest age increases in false memory and the largest age declines in net accuracy.     

The effect of modification of expressive displays on vicarious emotional arousal

Several recent experiments have demonstrated that modulation of the facial expressive response is accompanied by changes in autonomic arousal and subjective response to painful stimuli. The present study asked whether facial self-regulation may also bring about changes in covert vicarious emotional experience. Three groups of subjects were exposed to a videotaped model displaying intermittent pain to shock in a differential vicarious autonomic conditioning paradigm. Subjects in the inhibit and amplify groups were asked, respectively, (a) to inhibit their facial muscles or (b) to pose a facial response of pain when the model was shocked. It was predicted that the inhibit group would show less autonomic arousal to the model's expressive display (empathy) and less conditioning (as measured by skin conductance and heart rate change), and the amplify group more empathy and conditioning, than a third group who was given no facial instruction. In fact, the amplify group showed more skin conductance arousal, heart rate acceleration, and activity in response to the model's expressive display of pain than did the other two groups (which were not different from each other), but no more autonomic or facial conditioning. The overall pattern of physiological data is interpreted as generally supportive of a facial feedback theory of emotion: where significant between-groups' differences were obtained in facial activity, as in vicarious instigation, autonomic arousal differences also emerged; where no expressive differences were obtained, as in vicarious conditioning, no differences in autonomic arousal were found.