Priming effects on the N400 in the affective priming paradigm with facial expressions of emotion

We studied the effect of facial expression primes on the evaluation of target words through a variant of the affective priming paradigm. In order to make the affective valence of the faces irrelevant to the task, the participants were assigned a double prime–target task in which they were unpredictably asked either to identify the gender of the face or to evaluate whether the word was pleasant or unpleasant. Behavioral and electrophysiological (event-related potential, or ERP) indices of affective priming were analyzed. Temporal and spatial versions of principal components analyses were used to detect and quantify those ERP components associated with affective priming. Although no significant behavioral priming was observed, electrophysiological indices showed a reverse priming effect, in the sense that the amplitude of the N400 was higher in response to congruent than to incongruent negative words. Moreover, a late positive potential (LPP), peaking around 700 ms, was sensitive to affective valence but not to prime–target congruency. This pattern of results is consistent with previous accounts of ERP effects in the affective priming paradigm that have linked the LPP with evaluative priming and the N400 with semantic priming. Our proposed explanation of the N400 priming effects obtained in the present study is based on two assumptions: a double check of affective stimuli in terms of valence and specific emotion content, and the differential specificities of facial expressions of positive and negative emotions.     

Unconscious processing of dichoptically masked words

In three experiments, the subjects' task was to decide whether each of a series of words connoted something good (e.g., fame, comedy, rescue) or bad (stress, detest, malaria). One-half second before the presentation of each such target word, an evaluatively polarized priming word was presented briefly to the nondominant eye and was masked dichoptically by either the rapidly following (Experiment 1) or simultaneous (Experiments 2 and 3) presentation of a random letter-fragment pattern to the dominant eye. (The effectiveness of the masking procedure was demonstrated by the subjects' inability to discriminate the left vs. right position of a test series of words.) In all experiments, significant masked priming effects were obtained; evaluative decisions to congruent masked prime-target combinations (such as a positive masked prime followed by a positive target) were significantly faster than those to incongruent (e.g., negative prime/positive target) or noncongruent (e.g., neutral prime/positive target) combinations. Also, in two of the three experiments, when subjects were at chance accuracy in discriminating word position, their position judgments were nevertheless significantly influenced by the irrelevant semantic content (LEFT vs. RIGHT) of the masked position-varying words. The series of experiments demonstrated that two very different tasks--speeded judgment of evaluative meaning and nonspeeded judgment of word position--yielded statistically significant and replicable influences of the semantic content of apparently undetectable words. Coupled with previous research by others using the lexical decision task, these findings converge in establishing the reliability of the empirical phenomenon of semantic processing of words that are rendered undetectable by dichoptic pattern masking.     

About the impact of automaticity in the minimal group paradigm: evidence from affective priming tasks

Two experiments examined whether novel, minimal ingroups are automatically associated with positive affect while outgroups do not elicit such positive evaluative default. Participants were assigned to social categories in a typical minimal group setting and subsequently administered a masked priming task, i.e. prime words were not consciously recognized. Following either the presentation of a priori positive or negative words or the presentation of the group labels, participants classified adjectives with regard to their valence (positive/negative). In Experiment 1, a standard affective priming paradigm was realized with response latencies as dependent measures; in Experiment 2, a response window technique was used, with errors as crucial measure. In both studies, significant affective congruency effects emerged similarly for standard primes and category labels, indicating ingroup bias on an implicit level. Copyright © 1999 John Wiley & Sons, Ltd.     

Affective priming as an indirect measure of food preferences acquired through odor conditioning

The present study aimed at investigating affective priming for originally neutral food stimuli that recently acquired their affective meaning through odor conditioning. In a first phase, pictures of different brands of yogurts (CSs) were contingently presented with a positive or negative odor (US). In a subsequent phase, the yogurt CSs were used as primes in an affective priming procedure. Rating data showed that the acquisition procedure resulted in a reliable evaluative learning effect. This could be corroborated by the results of the priming task. Participants responded faster to positive target words and made fewer errors when they were preceded by a CS that had been associated with a positive odor, as compared to a CS that was associated with a negative odor. A reversed pattern was present for negative targets. Based on these findings, it is suggested that affective priming might be used as a demand-free measure of evaluative learning.     

The positivity proportion effect: A list context effect in masked affective priming

In the evaluative decision task, participants decide whether target words denote something positive or negative. Positive and negative prime words are known to engender so-called affective priming effects in this task. Primes were sandwich masked, and the proportion of positive to negative target words was manipulated. In Experiment 1, prime valence and positivity proportion interacted, so that primes of the less frequently presented target valence caused larger priming effects. Experiment 2 rendered an explanation of this interaction in terms of response bias unlikely, Experiment 3 ruled out a peripheral locus of the effect, and Experiment 4 ruled out an account in terms of stimulus repetition. The effect is explained by means of an attentional bias favoring the rare kind of valence.     

Affective priming with pictures of emotional scenes: the role of perceptual similarity and category relatedness

Prime pictures portraying pleasant or unpleasant scenes were briefly presented (150-ms display; SOAs of 300 or 800 ms), followed by probe pictures either congruent or incongruent in emotional valence. In an evaluative decision task, participants responded whether the probe was emotionally positive or negative. Affective priming was reflected in shorter response latencies for congruent than for incongruent prime-probe pairs. Although this effect was enhanced by perceptual similarity between the prime and the probe, it also occurred for probes that were physically different, and the effect generalized across semantic categories (animals vs. people). It is concluded that affective priming is a genuine phenomenon, in that it occurs as a function of stimulus emotional content, in the absence of both perceptual similarity and semantic category relatedness between the prime and the probe.     

I like the sound of your voice: Affective learning about vocal signals

This paper provides the first demonstration that the content of a talker’s speech is sufficient to imbue the acoustics of his voice with affective meaning. In two studies, participants listened to male talkers utter positive, negative, or neutral words. Next, participants completed a sequential evaluative priming task where a neutral word spoken by one of talkers was presented before each target word to be evaluated. We predicted, and found, that voices served as evaluative primes influencing the speed with which participants evaluated the target words. These two experiments demonstrate that the human voice can take on affective meaning merely based on the positive or negative value words it has spoken. Implications for affective processing, the pragmatics of communication, and person perception are discussed.     

Electrophysiological responses to evaluative priming: the LPP is sensitive to incongruity

Previous studies examining event-related potentials and evaluative priming have been mixed; some find evidence that evaluative priming influences the N400, whereas others find evidence that it affects the late positive potential (LPP). Three experiments were conducted using either affective pictures (Experiments 1 and 2) or words (Experiment 3) in a sequential evaluative priming paradigm. In line with previous behavioral findings, participants responded slower to targets that were evaluatively incongruent with the preceding prime (e.g., negative preceded by positive) compared to evaluatively congruent targets (e.g., negative preceded by negative). In all three studies, the LPP was larger to evaluatively incongruent targets compared to evaluatively congruent ones, and there was no evidence that evaluative incongruity influenced the N400 component. Thus, the present results provide additional support for the notion that evaluative priming influences the LPP and not the N400. We discuss possible reasons for the inconsistent findings in prior research and the theoretical implications of the findings for both evaluative and semantic priming.     

A different kind of pain: affective valence of errors and incongruence*

People hiss and swear when they make errors, frown and swear again when they encounter conflicting information. Such error- and conflict-related signs of negative affect are found even when there is no time pressure or external reward and the task itself is very simple. Previous studies, however, provide inconsistent evidence regarding the affective consequences of resolved conflicts, that is, conflicts that resulted in correct responses. We tested whether response accuracy in the Eriksen flanker task will moderate the effect of trial incongruence using affective priming to measure positive and negative affect. We found that responses to incongruent trials elicit positive affect irrespective of their accuracy. Errors, in turn, result in negative affect irrespective of trial congruence. The effects of conflicts and errors do not interact and affect different dimensions of affective priming. Conflicts change the speed of evaluative categorisation while errors are reflected in categorisation accuracy. We discuss the findings in light of the “reward value and prediction” model and the “affect as a feedback for predictions” framework and consider the possible mechanisms behind the divergent effects.     

情绪干扰听觉反应冲突的ERP研究

采用ERP技术研究13例正常青年人在声音诱发的不同情绪条件下,对反应抑制加工过程的影响,并试图阐明其潜在脑机制。实验中选择正、中、负三种声音各50种,作为诱发情绪的刺激材料。结果发现Go条件下的反应时在负性、中性、正性条件下依次减短;Go与Nogo刺激均诱发出显著的N1成分,中性条件下波幅显著大于正负性情绪条件。此外,三种情绪背景下, Nogo刺激诱发出显著的N2与P3成分。Nogo-N2主要分布在头皮前中部,在Fz点波幅最大。Nogo-P3主要分布在头皮中部,Pz点波幅最大。中性条件下Nogo-N2波幅显著大于负性与正性条件,而正性和负性之间差异不显著。行为结果表明,听觉负性情绪诱发对反应执行有干扰作用;ERP结果表明声音诱发的情绪对早期听觉选择性注意具有调节作用。听觉情绪诱发对反应抑制加工过程有显著影响,且该影响在早期反应冲突监控阶段最为明显。     

The influence of selection for response on repetition priming of word identification.

Repetition priming of word identification was examined using study tasks that required participants either to search for targets appearing in rapid serial visual presentation of word lists or to read aloud a list of target words. Nontarget words embedded in search lists produced a small amount of repetition priming on a masked word identification test, independent of presentation duration in the search list (200-1,000 ms), but no priming when they appeared as targets in a second search task used at test. For both test tasks, words that were originally encoded in a read-aloud task or served as detected targets during a search task generated more priming than nontarget words from search lists. These results suggest that priming effects are strongest when study tasks require an item to be selected as the basis for an overt response, even though the information on which study and test responses are based may be different.     

Word frequency effect on repetition priming as a function of prime duration and delay between the prime and the target

Two experiments studied the necessary conditions for the occurrence of repetition priming and word frequency effect on priming in a lexical decision task. To examine the role of prime processing duration, the prime was presented either for 50 ms or for 700 ms, and an interfering task was introduced between the prime and the target in order to restrict the time during which the prime was effectively processed and to limit it to exactly 50 ms or 700 ms. The interstimulus interval (ISI) between the prime and the target was 1500 ms or 3000 ms in Expt 1, and 600 ms in Expt 2. With primes presented for 50 ms, repetition priming effects were not dependent on target frequency, decreased with an increase of the ISI, and were no longer significant with an ISI of 3000 ms. With primes presented for 700 ms, repetition priming was systematically larger for low‐frequency words than for high‐frequency words, and remained reliable even with an ISI of 3000 ms. Thus, a minimum of prime duration was required both for maintaining repetition priming effects over more than some hundreds of milliseconds and for the occurrence of frequency effect on repetition priming. Theoretical interpretations of these results are discussed.     

Contingency learning with evaluative stimuli: testing the generality of contingency learning in a performance paradigm

In two experiments, we tested the generality of the learning effects in the recently-introduced color-word contingency learning paradigm. Participants made speeded evaluative judgments to valenced target words. Each of a set of distracting nonwords was presented most often with either positive or negative target words. We observed that participants responded faster on trials that respected these contingencies than on trials that contradicted the contingencies. The contingencies also produced changes in liking: in a subsequent explicit evaluative rating task, participants rated positively-conditioned nonwords more positively than negatively-conditioned nonwords. Interestingly, contingency effects in the performance task correlated with this explicit rating effect in both experiments. In Experiment 2, all effects reported were independent of subjective and objective contingency awareness (which was completely lacking), even when awareness was measured at the item level. Our results reveal that learning in this type of performance task extends to nonword-valence contingencies and to responses different from those emitted during the performance task. We discuss the implications of these findings for theories about the processes that underlie contingency learning in performance tasks and for research on evaluative conditioning.     

Biases in evaluation of neutral words due to motor compatibility effect

This study aims to demonstrate the effect of action fluency on emotional evaluation, specifically to show that neutral words can be evaluated positively or negatively depending on motor activity and evaluative setting. Right-handers naturally tend to associate positive (negative) valence to the right (left) part of space (Casasanto, 2009). We extend these associations to lateralized behaviors by studying the combined effect of motor fluency of lateral arm movements and the evaluative scale on the subjective evaluation of neutral words. Three experiments evidenced that, for right-handers, the realization of fluent rightward arm movements and the use of an evaluative scale congruent with their valence/laterality associations (left negative, right positive) led to a positive evaluation of neutral words, while non-fluent leftward movements and an incongruent scale led to a negative evaluation. This study demonstrates that emotion–action associations are experience-based, and influenced by functional and situational constraints.     

Task switches under Go/NoGo conditions and the decomposition of switch costs

Alternating switches between two simple S-R tasks are combined with Go/NoGo tasks. Non-switches after Go trials are assumed to selectively profit from stimulus driven repetition benefits, whereas switches after NoGo trials are assumed to be selectively delayed by stimulus driven negative priming. Intentionally driven reconfiguration costs are assessed by RT differences between switches after Go trials (no negative priming) and non-switches after NoGo trials (no repetition benefits). Experiment 1 indicates that with short preparation time repetition benefits, negative priming costs, and intentional components contribute approximately additively to switch costs. Experiment 2 confirms that the delay of switches after NoGo trials is indeed due to negative priming. Experiments 3 and 4 show that repetition benefits and intentional components of switch costs are properly assessed only if the settings assure that participants reconfigure the required task set in NoGo as well as Go trials.     

Evaluative priming from subliminal emotional words: Insights from event-related potentials and individual differences related to anxiety

The present ERP study investigated effects of subliminal emotional words on preference judgments about subsequent visual target stimuli (paintings, portraits). Each target was preceded by a masked 17-ms emotional adjective. Four classes of prime words were distinguished according to the combinations of positive/negative valence and high/low arousal. Targets were liked significantly more after positive-arousing primes (e.g., happy), relative to negative-arousing (brutal), positive-nonarousing (mild), and negative-nonarousing primes (lazy). In the target ERP, amplitude of right-hemisphere positive slow wave was increased after positive-arousing compared to negative-arousing primes. Evaluative priming effects on judgments and ERPs were more pronounced in high state-anxious participants. The results suggest that (1) there is indeed affective/semantic processing of unconscious words, (2) evaluative priming operates relatively late during target processing, (3) to be effective, prime words need to score high on the arousal dimension, and (4) individual differences in state anxiety modulate the susceptibility to subliminal evaluative priming.     

Automatically activated facets of ageism: Masked evaluative priming allows for a differentiation of age‐related prejudice

This study investigated the automatic activation of ageism by using a go/no‐go version of the masked evaluative priming task. Pictures of younger persons, of older persons in everyday contexts, and of older persons depicting age‐related conditions of decline were used as masked primes that preceded positive and negative target adjectives conveying either other‐relevant valence (e.g., just and mean) or possessor‐relevant valence (e.g., serene and lonely). The evaluative priming effect (denoting relative negativity of old‐everyday primes in comparison with younger primes) was significant, as hypothesized, only for possessor‐relevant targets. It was not moderated by explicit ageism. A second priming index (denoting relative negativity of old‐decline primes in comparison with old‐everyday primes) predicted, however, explicit ageism. Again, this result was, as expected, constrained to the index based on possessor‐relevant targets. This study provides further evidence that prejudice in terms of automatic evaluations of social stimuli can be more fine grained beyond a mere one‐dimensional positive–negative differentiation. Copyright © 2012 John Wiley & Sons, Ltd.     

高社交焦虑个体对正性面孔的解释偏差

本研究采用情绪启动范式考察社交焦虑个体对正性刺激解释偏差。研究以正性和打碎的面孔为启动项,正性或负性非社交词为目标项,要求高社交焦虑组被试和控制组被试判断目标项的情感色彩,并记录其反应时与准确率。结果发现,两组被试具有不同的情绪启动模式：高焦虑组被试未表现出显著地相容性效应;他们在正性-正性条件下的反应时显著慢于控制组被试。研究结果提示高社交焦虑个体具有对正性社交刺激的解释偏差,他们不能充分理解正性社交刺激的积极含义。     

How to switch on and switch off semantic priming effects for natural and artifactual categories: activation processes in category memory depend on focusing specific feature dimensions

"Semantic priming" refers to the phenomenon that people react faster to target words preceded by semantically related rather than semantically unrelated words. We wondered whether momentary mind sets modulate semantic priming for natural versus artifactual categories. We interspersed a category priming task with a second task that required participants to react to either the perceptual or action features of simple geometric shapes. Focusing on perceptual features enhanced semantic priming effects for natural categories, whereas focusing on action features enhanced semantic priming effects for artifactual categories. In fact, significant priming effects emerged only for those categories thought to rely on the features activated by the second task. This result suggests that (a) priming effects depend on momentary mind set and (b) features can be weighted flexibly in concept representations; it is also further evidence for sensory-functional accounts of concept and category representation.