Monday, April 21, 2008

ARTICLE UPDATE - The affective regulation of cognitive priming.

Storbeck J, Clore GL.

Emotion, 8, 208-215

Semantic and affective priming are classic effects observed in cognitive and social psychology, respectively. The authors discovered that affect regulates such priming effects. In Experiment 1, positive and negative moods were induced before one of three priming tasks; evaluation, categorization, or lexical decision. As predicted, positive affect led to both affective priming (evaluation task) and semantic priming (category and lexical decision tasks). However, negative affect inhibited such effects. In Experiment 2, participants in their natural affective state completed the same priming tasks as in Experiment 1. As expected, affective priming (evaluation task) and category priming (categorization and lexical decision tasks) were observed in such resting affective states. Hence, the authors conclude that negative affect inhibits semantic and affective priming. These results support recent theoretical models, which suggest that positive affect promotes associations among strong and weak concepts, and that negative affect impairs such associations (Clore & Storbeck, 2006; Kuhl, 2000).

ARTICLE UPDATE - I know how you feel: task-irrelevant facial expressions are spontaneously processed at a semantic level.

Preston SD, Stansfield RB.

Cognitive, Affective and Behavioral Neuroscience, 8, 54-64.

Previous studies have demonstrated that emotions are automatically processed. Even with subliminal presentations, subjects involuntarily mimic specific facial expressions, are influenced by the valence of a preceding emotion during judgments, and exhibit slowed responses to personally meaningful emotions; these effects are due to reflexive mimicry, unconscious carryover of valence, and attentional capture, respectively. However, perception-action effects indicate that rapid processing should involve deep, semantic-level representations of emotion (e.g., "fear"), even in the absence of a clinical emotion disorder. To test this hypothesis, we developed an emotional Stroop task (Emostroop) in which subjects responded nonverbally to emotion words superimposed over task-irrelevant images of faces displaying congruent or incongruent emotional expressions. Subjects reliably responded more slowly to incongruent than to congruent stimuli, and this interference was related to trait measures of emotionality. Rapid processing of facial emotions spontaneously activates semantic, content-rich representations at the level of the specific emotion.

ARTICLE UPDATE - Emotional priming of pop-out in visual search.

Lamy D, Amunts L, Bar-Haim Y.

Emotion, 8, 151-161

When searching for a discrepant target along a simple dimension such as color or shape, repetition of the target feature substantially speeds search, an effect known as feature priming of pop-out (V. Maljkovic and K. Nakayama, 1994). The authors present the first report of emotional priming of pop-out. Participants had to detect the face displaying a discrepant expression of emotion in an array of four face photographs. On each trial, the target when present was either a neutral face among emotional faces (angry in Experiment 1 or happy in Experiment 2), or an emotional face among neutral faces. Target detection was faster when the target displayed the same emotion on successive trials. This effect occurred for angry and for happy faces, not for neutral faces. It was completely abolished when faces were inverted instead of upright, suggesting that emotional categories rather than physical feature properties drive emotional priming of pop-out. The implications of the present findings for theoretical accounts of intertrial priming and for the face-in-the-crowd phenomenon are discussed.

ARTICLE UPDATE - The persistence of attention to emotion: Brain potentials during and after picture presentation.

Hajcak G, Olvet DM.

Emotion, 8, 250-255

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.

ARTICLE UPDATE - Emotion and working memory: Evidence for domain-specific processes for affective maintenance.

Mikels JA, Reuter-Lorenz PA, Beyer JA, Fredrickson BL.

Emotion, 8, 256-266

Working memory is comprised of separable subsystems for visual and verbal information, but what if the information is affective? Does the maintenance of affective information rely on the same processes that maintain nonaffective information? The authors address this question using a novel delayed-response task developed to investigate the short-term maintenance of affective memoranda. Using selective interference methods the authors find that a secondary emotion-regulation task impaired affect intensity maintenance, whereas secondary cognitive tasks disrupted brightness intensity maintenance, but facilitated affect maintenance. Additionally, performance on the affect maintenance task depends on the valence of the maintained feeling, further supporting the domain-specific nature of the task. The importance of affect maintenance per se is further supported by demonstrating that the observed valence effects depend on a memory delay and are not evident with simultaneous presentation of stimuli. These findings suggest that the working memory system may include domain-specific components that are specialized for the maintenance of affective memoranda.

ARTICLE UPDATE - Although there are many well-characterized affective visual stimuli sets available to researchers, there are few auditory sets availa

Levens SM, Phelps EA.

Emotion, 8, 267-280

The interaction between emotion and working memory maintenance, load, and performance has been investigated with mixed results. The effect of emotion on specific executive processes such as interference resolution, however, remains relatively unexplored. In this series of studies, we examine how emotion affects interference resolution processes within working memory by modifying the Recency-probes paradigm (Monsel, 1978) to include emotional and neutral stimuli. Reaction time differences were compared between interference and non-interference trials for neutral and emotional words (Studies 1 & 3) and pictures (Study 2). Our results indicate that trials using emotional stimuli show a relative decrease in interference compared with trials using neutral stimuli, suggesting facilitation of interference resolution in the former. Furthermore, both valence and arousal seem to interact to produce this facilitation effect. These findings suggest that emotion facilitates response selection amid interference in working memory.

ARTICLE UPDATE - Affective auditory stimuli: characterization of the International Affective Digitized Sounds (IADS) by discrete emotional categories.

Stevenson RA, James TW.

Behavioural Research Methods, 40, 315-320

Although there are many well-characterized affective visual stimuli sets available to researchers, there are few auditory sets available. Those auditory sets that are available have been characterized primarily according to one of two major theories of affect: dimensional or categorical. Current trends have attempted to utilize both theories to more fully understand emotional processing. As such, stimuli that have been thoroughly characterized according to both of these approaches are exceptionally useful. In an effort to provide researchers with such a stimuli set, we collected descriptive data on the International Affective Digitized Sounds (IADS), identifying which discrete categorical emotions are elicited by each sound. The IADS is a database of 111 sounds characterized along the affective dimensions of valence, arousal, and dominance. Our data complement these characterizations of the IADS, allowing researchers to control for or manipulate stimulus properties in accordance with both theories of affect, providing an avenue for further integration of these perspectives. Related materials may be downloaded from the Psychonomic Society Web archive at www.psychonomic.org/archive.

ARTICLE UPDATE - Amygdala contribution to selective dimensions of emotion.

Berntson GG, Bechara A, Damasio H, Tranel D, Cacioppo JT.

Social, Cognitive and Affective Neuroscience, 2, 123-129

The amygdala has been implicated in emotional processes, although the precise nature of the emotional deficits following amygdala lesions remains to be fully elucidated. Cognitive disturbances in the perception, recognition or memory of emotional stimuli have been suggested by some, whereas others have proposed changes in emotional arousal. To address this issue, measures of emotional arousal and valence (positivity and negativity) to a graded series of emotional pictures were obtained from patients with lesions of the amygdala and from a clinical contrast group with lesions that spared this structure. Relative to the contrast group, patients with damage to the amygdala evidenced a complete lack of an arousal gradient across negative stimuli, although they displayed a typical arousal gradient to positive stimuli. These results were not attributable to the inability of amygdala patients to process the hostile or hospitable nature of the stimuli, as the amygdala group accurately recognized and categorized both positive and negative features of the stimuli. The relative lack of emotional arousal to negative stimuli may account for many of the clinical features of amygdala lesions.

ARTICLE UPDATE - Chronometric features of processing unpleasant stimuli: a functional MRI-based transcranial magnetic stimulation study.

Kaffenberger T, Baumgartner T, Koeneke S, Jäncke L, Herwig U.

Neuroreport, 19, 777-781

The quick identification of potentially threatening events is a crucial cognitive capacity to survive in a changing environment. Previous functional MRI data revealed the right dorsolateral prefrontal cortex and the region of the left intraparietal sulcus (IPS) to be involved in the perception of emotionally negative stimuli. For assessing chronometric aspects of emotion processing, we applied transcranial magnetic stimulation above these areas at different times after negative and neutral picture presentation. An interference with emotion processing was found with transcranial magnetic stimulation above the dorsolateral prefrontal cortex 200-300 ms and above the left intraparietal sulcus 240/260 ms after negative stimuli. The data suggest a parallel and conjoint involvement of prefrontal and parietal areas for the identification of emotionally negative stimuli.

Monday, April 14, 2008

ARTICLE UPDATE - The amygdala and the experience of affect.

Barrett LF, Bliss-Moreau E, Duncan SL, Rauch SL, Wright CI.

Social Cognitive Affective Neuroscience, 2, 73-83

The current study examined the hypothesis that amygdala activation serves as a neural precondition for negative affective experience. Participants' affective experience was measured by asking them to report on their momentary experiences several times a day over the course of a month using an electronic experience-sampling procedure. One year later, participants viewed backwardly masked depictions of fear while functional magnetic resonance imaging was used to measure their amygdala and fusiform gyrus activation. Negative affect, as measured during the experience-sampling procedure 1-year prior, was positively correlated with amygdala activation in response to these brief presentations of fear depictions. Furthermore, descriptive analyses indicated that fusiform gyrus activation and negative affective experience in the scanner were associated for participants reporting increased nervousness during the imaging procedure. The results are consistent with the interpretation that the amygdala contributes to negative affective experience by increasing perceptual sensitivity for negative stimuli.

ARTICLE UPDATE - Prefrontal cortex damage abolishes brand-cued changes in cola preference.

Koenigs M, Tranel D.

Social Cognitive Affective Neuroscience, 3, 1-6

Human decision-making is remarkably susceptible to commercial advertising, yet the neurobiological basis of this phenomenon remains largely unexplored. With a series of Coke and Pepsi taste tests we show that patients with damage specifically involving ventromedial prefrontal cortex (VMPC), an area important for emotion, did not demonstrate the normal preference bias when exposed to brand information. Both comparison groups (neurologically normal adults and lesion patients with intact VMPC) preferred Pepsi in a blind taste test, but in subsequent taste tests that featured brand information ('semi-blind' taste tests), both comparison groups' preferences were skewed toward Coke, illustrating the so-called 'Pepsi paradox'. Like comparison groups, the VMPC patients preferred Pepsi in the blind taste test, but unlike comparison groups, the VMPC patients maintained their Pepsi preference in the semi-blind test. The result that VMPC damage abolishes the 'Pepsi paradox' suggests that the VMPC is an important part of the neural substrate for translating commercial images into brand preferences.

ARTICLE UDPATE - Basic tastes and basic emotions: Basic problems and perspectives for a nonbasic solution.

Sander D.

Behavioural Brain Research, 31, 88.

Contemporary behavioral and brain scientists consider the existence of so-called basic emotions in a similar way to the one described by Erickson for so-called basic tastes. Commenting on this analogy, I argue that similar basic problems are encountered in both perspectives, and I suggest a potential nonbasic solution that is tested in emotion research (i.e., the appraisal model of emotion).

ARTICLE UPDATE - Beyond fear: rapid spatial orienting toward positive emotional stimuli.

Brosch T, Sander D, Pourtois G, Scherer KR.

Psychological Science, 19, 362-370

There is much empirical evidence for modulation of attention by negative-particularly fear-relevant-emotional stimuli. This modulation is often explained in terms of a fear module. Appraisal theories of emotion posit a more general mechanism, predicting attention capture by stimuli that are relevant for the needs and goals of the organism, regardless of valence. To examine the brain-activation patterns underlying attentional modulation, we recorded event-related potentials from 20 subjects performing a dot-probe task in which the cues were fear-inducing and nurturance-inducing stimuli (i.e., anger faces and baby faces). Highly similar validity modulation was found for the P1 time-locked to target onset, indicating early attentional capture by both positive and negative emotional stimuli. Topographic segmentation analysis and source localization indicate that the same amplification process is involved whether attention orienting is triggered by negative, fear-relevant stimuli or positive, nurturance-relevant stimuli. These results confirm that biological relevance, and not exclusively fear, produces an automatic spatial orienting toward the location of a stimulus.

Monday, April 07, 2008

ARTICLE UPDATE - Affective incoherence: When affective concepts and embodied reactions clash.

Centerbar DB, Schnall S, Clore GL, Garvin ED.

Journal of Personality and Social Psychology, 94, 560-578

In five studies, the authors examined the effects on cognitive performance of coherence and incoherence between conceptual and experiential sources of affective information. The studies crossed the priming of happy and sad concepts with affective experiences. In different experiments, these included approach or avoidance actions, happy or sad feelings, and happy or sad expressive behaviors. In all studies, coherence between affective concepts and affective experiences led to better recall of a story than did affective incoherence. The authors suggest that the experience of such experiential affective cues serves as evidence of the appropriateness of affective concepts that come to mind. The results suggest that affective coherence has epistemic benefits and that incoherence is costly in terms of cognitive performance.

ARTICLE UPDATE - Selective Attention to Affective Value Alters How the Brain Processes Olfactory Stimuli.

Rolls ET, Grabenhorst F, Margot C, da Silva MA, Velazco MI.

Journal of Cognitive Neuroscience, in press

How does selective attention to affect influence sensory processing? In an functional magnetic resonance imaging investigation, when subjects were instructed to remember and rate the pleasantness of a jasmin odor, activations were greater in the medial orbito-frontal and pregenual cingulate cortex than when subjects were instructed to remember and rate the intensity of the odor. When the subjects were instructed to remember and rate the intensity, activations were greater in the inferior frontal gyrus. These top-down effects occurred not only during odor delivery but started in a preparation period after the instruction before odor delivery, and continued after termination of the odor in a short-term memory period. Thus, depending on the context in which odors are presented and whether affect is relevant, the brain prepares itself, responds to, and remembers an odor differently. These findings show that when attention is paid to affective value, the brain systems engaged to prepare for, represent, and remember a sensory stimulus are different from those engaged when attention is directed to the physical properties of a stimulus such as its intensity. This differential biasing of brain regions engaged in processing a sensory stimulus depending on whether the cognitive demand is for affect-related versus more sensory-related processing may be an important aspect of cognition and attention. This has many implications for understanding the effects not only of olfactory but also of other sensory stimuli.

ARTICLE UPDATE - Working Memory for Social Cues Recruits Orbitofrontal Cortex and Amygdala: A Functional Magnetic Resonance Imaging Study of Delayed M

Lopresti ML, Schon K, Tricarico MD, Swisher JD, Celone KA, Stern CE.

The Journal of Neuroscience, 28, 3718-3728.

During everyday interactions, we continuously monitor and maintain information about different individuals and their changing emotions in memory. Yet to date, working memory (WM) studies have primarily focused on mechanisms for maintaining face identity, but not emotional expression, and studies investigating the neural basis of emotion have focused on transient activity, not delay related activity. The goal of this functional magnetic resonance imaging study was to investigate WM for two critical social cues: identity and emotion. Subjects performed a delayed match-to-sample task that required them to match either the emotional expression or the identity of a face after a 10 s delay. Neuroanatomically, our predictions focused on the orbitofrontal cortex (OFC) and the amygdala, as these regions have previously been implicated in emotional processing and long-term memory, and studies have demonstrated sustained OFC and medial temporal lobe activity during visual WM. Consistent with previous studies, transient activity during the sample period representing emotion and identity was found in the superior temporal sulcus and inferior occipital cortex, respectively. Sustained delay-period activity was evident in OFC, amygdala, and hippocampus, for both emotion and identity trials. These results suggest that, although initial processing of emotion and identity is accomplished in anatomically segregated temporal and occipital regions, sustained delay related memory for these two critical features is held by the OFC, amygdala and hippocampus. These regions share rich connections, and have been shown previously to be necessary for binding features together in long-term memory. Our results suggest a role for these regions in active maintenance as well.