Emotional stimuli and context moderate effects of nicotine on specific but not global affects.

The authors tested the hypothesis that the effects of nicotine on affect are moderated by the presence or absence of emotionally positive and negative stimuli and by attentional choice to avoid attending to emotionally negative stimuli. Thirty-two habitual smokers were assigned to tasks allowing attentional freedom to look back and forth at 2 simultaneously presented pictures, whereas another 32 habitual smokers viewed single pictures without attentional choice. Picture contents in both tasks were 1 of 4 combinations: emotionally negative + neutral, negative + positive, positive + neutral, or neutral + neutral. Participants wore a nicotine patch on 1 day and placebo patch on another day. Nicotine reduced anxiety most when negative pictures were presented in combination with neutral pictures, but it had no effect on anxiety when negative pictures were presented in combination with positive pictures and when negative pictures were not presented. In contrast, nicotine only reduced depressive affect when the participant had attentional choice between positive and negative pictures. Nicotine also enhanced positive affect and reduced negative affect as measured by the Positive and Negative Affect Schedule, but these effects were not moderated by task manipulations. Overall, the findings support the view that nicotine's ability to reduce specific negative affects is moderated by emotional context and attentional freedom. Nicotine tended to enhance eye-gaze orientation to emotional pictures versus neutral pictures in women, but it had no significant effect on eye-gaze in men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing between automaticity and attention in the processing of emotionally significant stimuli.

There is contradicting evidence as to whether irrelevant but significant emotional stimuli can be processed outside the focus of attention. In the current study, participants were asked to ignore emotional and neutral pictures while performing a competing task. In Experiment 1, orienting of attention to distracting pictures was manipulated via a peripheral cue. In Experiment 2, attentional load was varied, either leaving spare attention to process the distracting pictures or, alternatively, depleting attentional resources. Although all pictures were task irrelevant, negative pictures were found to interfere more with performance in comparison to neutral pictures. This finding suggests that processing of negative stimuli is automatic in the sense that it does not require execution of conscious monitoring. However, interference occurred only when sufficient attention was available for picture processing. Hence, processing of negative pictures was dependent on sufficient attentional resources. This suggests that processing of emotionally significant stimuli is automatic yet requires attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective priming with subliminally presented pictures.

Affective priming studies have demonstrated that subliminally presented prime words can exert an influence on responses towards positive or negative target stimuli. In the present series of experiments, it was investigated whether these findings can be extended to pictorial stimuli. Ideographically selected positive, neutral, and negative picture primes that were sandwich-masked immediately preceded positive or negative target pictures (Experiment 1) or words (Experiments 2 & 3). Evaluative categorization responses to these target stimuli were significantly influenced by the valence of the prime. First, it was demonstrated that high anxious participants were selectively slowed when the subliminally presented prime was negative (Experiments 1 & 2). Second, the affective congruence between primes and targets also exerted an influence on the responses, but in a direction that is opposite to what is typically observed in affective priming research. These reverse priming effects are situated within a series of recent similar findings, and implications for theories of affective priming are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of unattended emotional visual scenes.

Prime pictures of emotional scenes appeared in parafoveal vision, followed by probe pictures either congruent or incongruent in affective valence. Participants responded whether the probe was pleasant or unpleasant (or whether it portrayed people or animals). Shorter latencies for congruent than for incongruent prime-probe pairs revealed affective priming. This occurred even when visual attention was focused on a concurrent verbal task and when foveal gaze-contingent masking prevented overt attention to the primes but only if these had been preexposed and appeared in the left visual field. The preexposure and laterality patterns were different for affective priming and semantic category priming. Affective priming was independent of the nature of the task (i.e., affective or category judgment), whereas semantic priming was not. The authors conclude that affective processing occurs without overt attention--although it is dependent on resources available for covert attention--and that prior experience of the stimulus is required and right-hemisphere dominance is involved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of nicotine and depressive traits on affective priming of lateralized emotional word identification.

Based on evidence suggesting that depressive traits, emotional information processing, and the effects of nicotine may be mediated by lateralized brain mechanisms, analyses assessed the influence of depressive traits and nicotine patch on emotional priming of lateralized emotional word identification in 61 habitual smokers. Consistent with hypotheses, nicotine as compared to placebo patch enhanced right visual field (RVF) emotional word identification while decreasing performance of emotional word identification in the left visual field (LVF). Nicotine also enhanced positive affect and decreased negative affect. Consistent with the Heller model of depression, scoring high in depressive traits was associated with a general decrease in LVF emotional word identification. Additionally, this general LVF deficit was especially pronounced for positive word identification in individuals scoring high in trait depression. Positive primes facilitated positive target identification in the RVF and negative primes facilitated negative target identification in the LVF. Thus, nicotine promoted a LVF word-identification deficit similar to that observed in those with depressive traits. However, nicotine also enhanced RVF processing and reduced negative affect, whereas it enhanced positive affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic Priming of Different Affective Categories.

The authors investigated affective semantic priming using a lexical decision task with 4 affective categories of related word pairs: neutral, happy, fearful, and sad. Results demonstrated a striking and reliable effect of affective category on semantic priming. Neutral and happy prime-targets yielded significant semantic priming. Fearful pairs showed no or modest priming facilitation, and sad primes slowed reactions to sad targets. A further experiment established that affective primes do not have generalized facilitatory-inhibitory effects. The results are interpreted as showing that the associative mechanisms that support semantic priming for neutral words are also shared by happy valence words but not for negative valence words. This may reflect increased vigilance necessary in adverse contexts or suggest that the associative mechanisms that bind negative valence words are distinct. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural response to emotional pictures is unaffected by concurrent task difficulty: An event-related potential study.

The late positive potential (LPP) is an event-related potential that is enhanced when viewing arousing (pleasant and unpleasant) pictures compared to neutral pictures. The affective modulation of the LPP is believed to reflect the increased attention to, and perceptual processing of, emotional stimuli. The present study examined whether concurrent task difficulty (performing mathematics) would modulate the LPP while participants viewed emotionally arousing stimuli. Results indicated that the LPP was larger following pleasant and unpleasant stimuli than it was following neutral stimuli; moreover, the magnitude of this increase was not influenced by concurrent task difficulty. This finding suggests that the affective modulation of neural activity during picture viewing is relatively automatic and is insusceptible to competing task demands. Results are further discussed in terms of the LPP's role in motivated attention and implications for research on emotion regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Late positive potential to appetitive stimuli and local attentional bias.

Predicated on the idea that positive affects high in approach motivation are crucial in goal-directed behaviors, research has found that these positive affects cause narrowed attention. The present research was designed to investigate a possible neurophysiological underpinning of this effect. Previous research has suggested that the late positive potential (LPP) of the event-related brain potential is increased by emotionally arousing stimuli because of the attention-grabbing nature of such stimuli. Other research has suggested that left prefrontal cortical regions are associated with narrowed attention and approach-motivated affect. Integrating these two lines of evidence, the present research examined LPPs to appetitive versus neutral pictures and assessed the relationship of these LPPs to local versus global attentional bias following the picture primes. Results revealed that appetitive in comparison with neutral pictures evoked larger LPP amplitudes bilaterally over central and parietal regions and asymmetrically over frontal regions. Moreover, these LPP amplitudes to appetitive pictures predicted greater locally biased attention caused by the appetitive pictures. These results provide the first evidence that LPPs are associated with the local attentional bias induced by appetitive motivation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional bias predicts outcome in smoking cessation.

Most attempts to quit smoking end in failure, with many quitters relapsing in the first few days. Responses to smoking-related cues may precipitate relapse. A modified emotional Stroop task-which measures the extent to which smoking-related words disrupt performance on a reaction time (RT) task-was used to index the distracting effects of smoking-related cues. Smokers (N=158) randomized to a high-dose nicotine patch (35 mg) or placebo patch completed the Stroop task on the 1st day of a quit attempt. Smokers using an active patch exhibited less attentional bias, making fewer errors on smoking related words. Smokers who showed greater attentional bias (slowed RT on the first block of smoking words) were significantly more likely to lapse in the short-term, even when controlling for self-reported urges at the test session. Attentional bias measures may tap an important component of dependence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain evoked potentials reflect how emotional faces influence our decision making.

Emotion is usually not discussed as a relevant variable in rational models of decision making—but may be one. The present electroencephalographic study demonstrates the influence of emotional primes (angry, happy faces) on purchase decisions. In a within-subject design, pictures of an apartment were shown to participants who then had to make Go/NoGo decisions on whether to rent it. Their decision should be based either on its price or on its brightness. In two thirds of the trials, emotional prime pictures of happy versus unhappy faces preceded the purchase target (apartment); in one third of the trials no prime was given. Response certainty was evaluated by means of reaction times (RT) and peak amplitude of the event-related potential N200. Facial primes accelerated decisions (RT) irrespective of affective expression. Positive face primes elicited larger N200 amplitudes during purchase decision compared to negative ones. Price-based decisions were made faster and elicited larger N200 than brightness-based decisions. These results support the cognitive-tuning model of decision making and validate the N200 as sensitive measure for the interplay of cognitive and affective aspects in decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological correlates of emotional responding in schizophrenia.

People with schizophrenia consistently report normal levels of pleasant emotion when exposed to evocative stimuli, suggesting intact consummatory pleasure. However, little is known about the neural correlates and time course of emotion in schizophrenia. This study used a well-validated affective picture viewing task that elicits a characteristic pattern of event-related potentials (ERPs) from early to later processing stages (i.e., P1, P2, P3, and late positive potentials [LPPs]). Thirty-eight stabilized outpatients with schizophrenia and 36 healthy controls viewed standardized pleasant, unpleasant, and neutral pictures while ERPs were recorded and subsequently rated their emotional responses to the stimuli. Patients and controls responded to the pictures similarly in terms of their valence ratings, as well as the initial ERP components (P1, P2, and P3). However, at the later LPP component (500–1,000 ms), patients displayed diminished electrophysiological discrimination between pleasant versus neutral stimuli. This pattern suggests that patients demonstrated normal self-reported emotional experience and intact initial sensory processing of and resource allocation to emotional stimuli. However, they showed a disruption in a later component associated with sustained attentional processing of emotional stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sustained and transient modulation of performance induced by emotional picture viewing.

We investigated how viewing task-irrelevant emotional pictures affects the performance of a subsequent nonemotional visual detection task. Subjects performed target-detection trials following the offset of individual unpleasant, pleasant, and neutral pictures. Sustained interference occurred when subjects viewed unpleasant pictures (mutilated bodies) in a sequential, "blocked" fashion. Such slowing down of reaction time appeared to build up with time, consistent with the instatement of a defensive emotional state. With a randomized picture presentation, only a transient interference effect was observed, consistent with increased attentional demands during the processing of unpleasant pictures. During blocked presentation of affiliative pleasant pictures, reaction times were faster, suggesting the activation of appetitive motivational systems. Ultimately, both attentional and motivational systems are intricately tied in the brain and, together, determine behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention and emotional vulnerability: Assessing the causal basis of their association through the experimental manipulation of attentional bias.

Although it is well-established that vulnerability to negative emotion is associated with attentional bias toward aversive information, the causal basis of this association remains undetermined. Two studies addressed this issue by experimentally inducing differential attentional responses to emotional stimuli using a modified dot probe task, and then examining the impact of such attentional manipulation on subsequent emotional vulnerability. The results supported the hypothesis that the induction of attentional bias should serve to modify emotional vulnerability, as revealed by participants' emotional reactions to a final standardized stress task. These findings provide a sound empirical basis for the previously speculative proposal that attentional bias can causally mediate emotional vulnerability, and they suggest the possibility that cognitive-experimental procedures designed to modify selective information processing may have potential therapeutic value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subliminal processing of smoking-related and affective stimuli in tobacco addiction.

Cognitive processing biases toward smoking-related and affective cues may play a role in tobacco dependence. Because processing biases may occur outside conscious awareness, the current study examined processing of smoking-related and affective stimuli presented at subliminal conditions. A pictorial subliminal repetition priming task was administered to three groups: (1) Nonsmokers (n = 56); (2) Smokers (≥10 cigarettes/day) who had been deprived from smoking for 12 h (n = 47); and (3) Nondeprived smokers (n = 66). Prime stimuli were presented briefly (17 ms) and were followed by a mask (to render them unavailable to conscious awareness) and then a target. Participants were required to make a speeded classification to the target. A posttask awareness check was administered to ensure that participants could not consciously perceive the briefly presented primes (i.e., smoking paraphernalia, neutral office supplies, and happy, angry, and neutral facial expressions). The groups differed in the degree to which they exhibited a processing bias for smoking-related stimuli, F(2, 166) = 4.99, p = .008. Deprived smokers exhibited a bias toward processing smoking (vs. neutral office supply) stimuli, F(1, 46) = 5.67, p = .02, whereas nondeprived smokers and nonsmokers did not (ps > .22). The three groups did not differ in the degree to which they exhibited a subliminal processing bias for affective stimuli. Tobacco deprivation appears to increase smokers' subliminal processing of smoking-related (vs. neutral) stimuli but does not influence subliminal processing of affective stimuli. Future research should investigate whether subliminal biases toward smoking-related stimuli influence relapse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of facial expressions of emotion during binocular rivalry.

Binocular rivalry is the perceptual alternation between two incompatible stimuli presented simultaneously but to each eye separately. The observer's perception switches back and forth between the two stimuli that are competing for perceptual dominance. In two studies, pictures of emotional faces (disgust and happy) were pitted against each other or against pictures of faces with neutral expressions. Study 1 demonstrated that (a) emotional facial expressions predominate over neutral expressions, and (b) positive facial expressions predominate over negative facial expression (i.e., positivity bias). Study 2 examined individual differences in emotional predominance and positivity bias during binocular rivalry. Although the positivity bias was not affected by the levels of depressive symptoms, results demonstrated that emotional predominance diminished as the level of depressive symptoms increased. These results indicate that individuals who report more depressive symptoms compared to their less depressed counterparts tend to assign more meaning to neutral faces. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional scenes in peripheral vision: Selective orienting and gist processing, but not content identification.

Emotional-neutral pairs of visual scenes were presented peripherally (with their inner edges 5.2° away from fixation) as primes for 150 to 900 ms, followed by a centrally presented recognition probe scene, which was either identical in specific content to one of the primes or related in general content and affective valence. Results indicated that (a) if no foveal fixations on the primes were allowed, the false alarm rate for emotional probes was increased; (b) hit rate and sensitivity (A') were higher for emotional than for neutral probes only when a fixation was possible on only one prime; and (c) emotional scenes were more likely to attract the first fixation than neutral scenes. It is concluded that the specific content of emotional or neutral scenes is not processed in peripheral vision. Nevertheless, a coarse impression of emotional scenes may be extracted, which then leads to selective attentional orienting or--in the absence of overt attention--causes false alarms for related probes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determinants and effects of attentional bias in smokers.

Much research has shown that individuals exhibit an attentional bias to stimuli related to their current concerns or pathologies. Using the emotional Stroop task, we investigated attentional bias in smokers. Ninety-six smokers either abstained from smoking for 24 hrs or smoked normally before color-naming smoking-related and neutral words. Both a blocked format (smoking and neutral words presented in separate blocks) and an unblocked format (smoking and neutral words presented in a mixed random sequence) were used. In the blocked format, abstinence caused an attentional bias to smoking-related stimuli, and the degree of attentional bias predicted the latency to the first cigarette of the morning. However, different results were obtained from the unblocked version of the task. We conclude that the emotional Stroop task is a useful tool to measure attentional bias in smokers and could be used in cessation studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)