Reduced memory for the spatial and temporal context of unpleasant words

Emotional stimuli are consistently better remembered than neutral stimuli. However, the reported effects of emotional stimuli on source memory are less consistent. In four experiments, we examined spatial and temporal source memory and free recall for emotional words previously studied in an fMRI experiment. In the fMRI experiment, the unpleasant but not the pleasant words were shown to activate the amygdala. In the experiments reported here, spatial and temporal source memory were reduced for the unpleasant words compared to pleasant and neutral words. Reduced spatial memory for unpleasant words was observed across studies that varied the specific stimuli, task conditions, and incidental versus intentional encoding instructions. Free recall was enhanced for the pleasant and unpleasant words compared to neutral words. The results demonstrate reduced source memory for unpleasant words even when item recall is enhanced. Our findings are consistent with prior reports of amygdala-mediated amnestic effects evoked by unpleasant stimuli.     

Well‐being and the accessibility of pleasant and unpleasant concepts

The trait–congruency hypothesis predicts that persons high in positive or negative trait affect more readily process pleasant or unpleasant stimuli, respectively. In two studies, participants were administered measures of personality and affect. Moreover, a yes/no lexical decision task with pleasant, unpleasant and neutral words was administered in Study 1, whereas a go/no‐go task was used in Study 2. Several methods to increase reliabilities of differences in reaction times are explored. Correlations of measures of personality and trait affect with decision times were mostly consistent with the trait–congruency hypothesis, particularly for decision times in the go/no‐go task that measured individual differences in valence‐specific decision times more reliably. The findings suggest that trait‐related concept accessibility is one source of trait congruity. Copyright © 2006 John Wiley & Sons, Ltd.     

Emotion-modulated performance and activity in left dorsolateral prefrontal cortex

Functional MRI (fMRI) was used to examine the relationship between processing of pleasant and unpleasant stimuli and activity in prefrontal cortex. Twenty volunteers identified the colors in which pleasant, neutral, and unpleasant words were printed. Pleasant words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant words. In addition, pleasant words prompted more activity in left than in right DLPFC. Response speed to pleasant words was correlated with DLPFC activity. These data directly link positive affect, enhanced performance, and prefrontal activity, providing some of the first fMRI evidence supporting models of emotional valence and frontal brain asymmetry based on electroencephalography (EEG).     

Mood congruence in childhood and recent autobiographical memory

To improve upon previous methodology, participants in musically induced happy, sad, or neutral moods were asked to recall childhood and recent autobiographical memories in response to pleasant, unpleasant, and neutral word cues. Symmetrical mood-congruent memory effects were observed when events were rated from the perspective of when they actually occurred (i.e., then), because memories rated as being unpleasant then tended to be rated as more pleasant now. Finally, pleasant and unpleasant cue words facilitated retrieval of childhood memories more than did neutral cues. These findings suggest that symmetrical mood congruence can be observed when accounting for such factors as the valence of retrieval cues and the perspective from which experiences are rated, given that memories appear to undergo change in affective labelling.     

Diminished response to pleasant stimuli by depressed women

This study examined the self-report and facial expressions of emotional response to pictorial stimuli and the incidental learning of pleasant and unpleasant words by depressed (n = 20) and nondepressed (n = 20) women. Depression was associated with reports of diminished emotional response and reduced frequency and intensity of facial expressions only to pleasant stimuli. The 2 groups did not differ in response to hedonically unpleasant stimuli, even those specifically relevant to the emotion of sadness. In a similar vein, depressed and nondepressed participants showed differences in incidental recall for only pleasant self-referential terms. There was no difference in recall of unpleasant words. These findings suggest the importance of hedonic deficits on psychological processes in clinical depression.     

Friendly drug-dealers and terrifying puppies: Affective primacy can attenuate the N400 effect in emotional discourse contexts

Words that are semantically congruous with their preceding discourse context are easier to process than words that are semantically incongruous with their context. This facilitation of semantic processing is reflected by an attenuation of the N400 event-related potential (ERP). We asked whether this was true of emotional words in emotional contexts where discourse congruity was conferred through emotional valence. ERPs were measured as 24 participants read two-sentence scenarios with critical words that varied by emotion (pleasant, unpleasant, or neutral) and congruity (congruous or incongruous). Semantic predictability, constraint, and plausibility were comparable across the neutral and emotional scenarios. As expected, the N400 was smaller to neutral words that were semantically congruous (vs. incongruous) with their neutral discourse context. No such N400 congruity effect was observed on emotional words following emotional discourse contexts. Rather, the amplitude of the N400 was small to all emotional words (pleasant and unpleasant), regardless of whether their emotional valence was congruous with the valence of their emotional discourse context. However, consistent with previous studies, the emotional words produced a larger late positivity than did the neutral words. These data suggest that comprehenders bypassed deep semantic processing of valence-incongruous emotional words within the N400 time window, moving rapidly on to evaluate the words’ motivational significance.     

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.     

Buzzwords: early cortical responses to emotional words during reading

Electroencephalographic event-related brain potentials were recorded as subjects read, without further instruction, consecutively presented sequences of words. We varied the speed at which the sequences were presented (3 Hz and 1 Hz) and the words' emotional significance. Early event-related cortical responses during reading differentiated pleasant and unpleasant words from neutral words. Emotional words were associated with enhanced brain responses arising in predominantly left occipito-temporal areas 200 to 300 ms after presentation. Emotional words were also spontaneously better remembered than neutral words. The early cortical amplification was stable across 10 repetitions, providing evidence for robust enhancement of early visual processing of stimuli with learned emotional significance and underscoring the salience of emotional connotations during reading. During early processing stages, emotion-related enhancement of cortical activity along the dominant processing pathway is due to arousal, rather than valence of the stimuli. This enhancement may be driven by cortico-amygdaloid connections.     

The self‐choice effects on memory and individual differences in emotional intelligence

The present study examined the self‐choice effects on intentional memory and the relation between individual differences in emotional intelligence, and the size of the self‐choice effects. Word pairs were supplied to the participants in either a self‐choice or forced‐choice condition. In the self‐choice condition the participants were asked to choose one of the words that elicited more pleasant or more unpleasant episodes, and to remember the chosen word. In the forced‐choice condition one of the paired words was underlined to signify that it was the word to remember. For participants who chose a word that elicited more pleasant episodes, self‐choice effects were observed in pleasant‐pleasant and pleasant‐unpleasant word pairs. However, for participants who were asked to choose a word that elicited more unpleasant episodes, the effects were found in unpleasant‐unpleasant and pleasant‐unpleasant word pairs. The size of the self‐choice effects was determined by the level of emotional intelligence.     

Processing of “unattended” threat-related information: Role of emotional content and context

Unpleasant, pleasant, or neutral visual scenes served as a context for the presentation of threat-related, positive, and neutral words. On each trial, 2 simultaneous prime words (one foveal, i.e., at fixation, and one parafoveal, i.e., 2.2° apart) appeared for 150 ms, followed by a foveally presented probe word in a lexical decision task. Results showed facilitation in response times for probe threat words when primed by an identical parafoveal word, in comparison with priming by an unrelated parafoveal word, and this effect was enhanced in an emotionally congruent unpleasant context. In contrast, no parafoveal effect appeared for positive words, even in a pleasant context. This reveals parallel processing of threat-related words outside the focus of attention.     

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.     

Perceptual,affective, and cognitive judgments of odors: pleasantness and handedness effects

The present study sought to examine the differential processing of pleasant, neutral, and unpleasant odors. The effects of the nostril stimulated (left or right) and the type of judgment (perceptual, affective, or cognitive) performed on the olfactory stimuli were also studied. To this end, 64 subjects were asked to smell pleasant, neutral, and unpleasant odors under four conditions (detection, intensity, pleasantness, and familiarity tasks). The participants were to perform these tasks as quickly as possible, while response times were recorded. The results showed that (i) unpleasant odors were assessed more rapidly than neutral or pleasant odors, and that this was specifically true (ii) during right nostril stimulation, and (iii) during pleasantness assessment, suggesting possible differential cerebral hemisphere involvement, with a right-side advantage for processing of unpleasant affect in olfaction. A handedness effect on familiarity judgment is also discussed.     

Reactions in Psychotherapy

The Pollyanna Principle states that people process pleasant information more accurately and efficiently than less pleasant information. This study examined whether different measures of Pollyanna tendencies are correlated with each other. Fourteen measures of Pollyannaism were derived for 133 students. The results showed that subjects who rated themselves as optimistic or happy also showed Pollyannaism on other measures of happiness, believed that the events in their lives were pleasant, gave themselves positive ratings on personality characteristics, recalled pleasant words more often than unpleasant words, supplied more free associations to pleasant stimuli than to unpleasant stimuli, listed pleasant items first, and judged that pleasant words were more frequent in the English language.     

Individual differences in Pollyannaism

The Pollyanna Principle states that people process pleasant information more accurately and efficiently than less pleasant information. This study examined whether different measures of Pollyanna tendencies are correlated with each other. Fourteen measures of Pollyannaism were derived for 133 students. The results showed that subjects who rated themselves as optimistic or happy also showed Pollyannaism on other measures of happiness, believed that the events in their lives were pleasant, gave themselves positive ratings on personality characteristics, recalled pleasant words more often than unpleasant words, supplied more free associations to pleasant stimuli than to unpleasant stimuli, listed pleasant items first, and judged that pleasant words were more frequent in the English language.     

Personality and modulation of the startle reflex by emotionally-toned filmclips

Several researchers have found that pleasant foreground stimuli attenuate the eyeblink component of the startle reflex while unpleasant foreground stimuli potentiate it. The effects of personality factors on such modulation of the eyeblink response, as measured by electromyographic (EMG) activity in reaction to loud acoustic startle probes, were examined in subjects viewing emotionally-toned (pleasant, unpleasant and neutral) filmclips. During the main part of the experiment, introverts had higher baseline EMG activity and lower response probability than extraverts; no differences were observed at the beginning of the experiment, during an acclimatization session. Reflex modulation, as measured by response latency, was influenced by the Psychoticism (P) factor of the Eysenck Personality Questionnaire: subjects high on P showed longer latencies to eyeblink onset when probed during viewing of pleasant filmclips than subjects low on this dimension; no significant differences were observed between subjects low and high on P for neutral and unpleasant filmclips. No influence of personality factors was found on affective modulation as measured by response amplitude/magnitude. The results are discussed in relation to Gray's and Eysenck's theories of personality.     

The effect of rumination on recall of emotional words: comparison of dysphoric individuals with and without a history of nonsuicidal self-injury

ABSTRACT

Prior research and theory has suggested that rumination plays a role in nonsuicidal self-injury (NSSI), and rumination increases recall of negative autobiographical information in dysphoric individuals. Across two studies, we investigated whether rumination (versus distraction) differentially influences the recall of emotional words among dysphoric persons with and without a history of NSSI. Participants encoded unpleasant, neutral, and pleasant words and then were randomly assigned to either focus on the meaning and consequences of their emotions (i.e. rumination) or unrelated thoughts (i.e. distraction) before they were asked to recall encoded words. Across the two studies, we did not find a significant effect of rumination on memory for emotional words among dysphoric people with (Studies 1 and 2) or without a history of NSSI (Study 1). We did find that people were more likely to remember neutral words as opposed to unpleasant or pleasant words across studies, regardless of rumination condition. Together, results from these two well-powered studies provide fairly compelling evidence that rumination after encoding has little to no effect on recall for emotional words in people elevated on symptoms of depression or with NSSI history. These findings can be used to refine theories of rumination and NSSI.     

The Sound of Smell: Associating Odor Valence With Disgust Sounds

Olfaction has recently been highlighted as a sense poorly connected with language. Odor is difficult to verbalize, and it has few qualities that afford mimicry by vision or sound. At the same time, emotion is thought to be the most salient dimension of an odor, and it could therefore be an olfactory dimension more easily communicated. We investigated whether sounds imitative of an innate disgust response can be associated with unpleasant odors. In two experiments, participants were asked to make a forced choice between a pseudoword including a disgust sound and a neutral pseudoword, for pleasant and unpleasant odors. Overall, participants chose more disgust pseudowords than neutral pseudowords for unpleasant odors, but this was not the case for pleasant odors. This effect was not driven by a general association between unpleasant sounds and unpleasant odors, but specifically the sounds [x/χ] and [f], thought to reflect physical responses to disgusting odors, as seen in the Polish fu! or the English ugh!. In line with growing evidence that language can encode odor, we provide the first experimental evidence for an association between the sound of a word and odor valence.     

The processing of affectively valenced stimuli: The role of surprise

Two experiments tested the hypothesis that the surprise mechanism activates a threat detection system that prioritises the processing of threat-related stimuli. In Experiment 1, participants responded to a dot that appeared during the presentation of two words. In the critical trial, one of the two words was either pleasant or unpleasant. In Experiment 2, depending on the condition, the participants had to decide whether at least one of two simultaneously presented pictures depicted either a pleasant or an unpleasant stimulus. In the critical trial, both a pleasant and an unpleasant picture appeared. In both experiments, the stimuli in the critical trial were presented either during routine behaviour or in the context of a surprising event. The results showed that during routine behaviour unpleasant stimuli received more attentive resources than pleasant stimuli only if the affective valence of the stimuli was action-relevant (Experiment 2). In contrast, in the context of surprise, unpleasant words engaged more attentive resources than pleasant words although they were action-irrelevant (Experiment 1). In addition, in the context of surprise, the decision time increase was more pronounced in the pleasant than in the unpleasant experimental group. This finding was interpreted as evidence that the threat detection system of the surprise mechanism initially searches for a threat-related stimulus.     

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.     

Emotion and motor preparation: A transcranial magnetic stimulation study of corticospinal motor tract excitability

In the present study, we examined whether preparing motor responses under different emotional conditions alters motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation delivered to the motor cortex. Analyses revealed three findings: (1) Reaction times were expedited during exposure to unpleasant images, as compared with pleasant and neutral images; (2) force amplitude was greater during exposure to unpleasant images, as compared with pleasant and neutral images; and (3) MEPs were larger while participants viewed unpleasant images, as compared with neutral images. Hence, coupling the preparation of motor responses with the viewing of emotional images led to arousal-driven changes in corticospinal motor tract excitability, whereas movement speed and force production varied as a function of emotional valence. These findings demonstrate that the effects of emotion on the motor system manifest at varying sensitivity levels across behavioral and neurophysiological measures. Moreover, they validate the action readiness component of emotional experience by demonstrating that emotional states influence the execution of future movements but, alone, do not lead to overt movement.