Automatic Stimulus Processing Research Articles

The influence of threat and aversive motivation on conflict processing in the Stroop task.

Motivated attention can be driven by the desire to maximize gains or escape punishment. In the Stroop task, when rewards can be obtained by responding quickly to certain colors, corresponding color words are prioritized and produce enhanced interference, suggesting transfer of an attentional bias from color hues to color words. In the present study, we replicated this transfer effect using reward and conducted a parallel experiment exchanging the prospect of reward (appetitive motivation) with the opportunity to avert punishment (aversive motivation). Participants were required to identify the color (hue) of color words and received electric shocks for responses to particular hues that were slow or incorrect. Shock-related words similarly impaired color-ink naming performance. In contrast to prior studies with reward, however, responding to hues associated with shock was also impaired, with threat producing an increase in error rate that ironically resulted in more frequent shocks. Our results suggest that aversive and appetitive motivation affect attention to task-relevant information differently, although each produces a common bias in automatic stimulus processing presumably driven by valence.

And one more for the road: Commentary on the Special Issue on alcohol and eyewitness memory

SummaryStudies examining the influence of alcohol intoxication have reported mixed findings on whether it impairs eyewitness memory. Although the studies in this Special Issue investigated different questions and tested different variables, the findings of these studies collectively provide insight into mechanisms and methodological issues that may explain the ambiguous findings of alcohol intoxication and eyewitness memory. In this commentary, we first describe the experimental studies of this Special Issue. We then discuss four mechanisms that could underlie those mixed findings (alcohol myopia, disinhibition, hypervigilance, and metacognitive processes at retrieval). Last, we address methodological issues that may have contributed to those ambiguous findings (i.e., alcohol intoxication levels, automatic processing of stimuli, sensitivity of dependent variables, and possible interactions with arousal) and provide suggestions for future research to address these issues.

Gender Differences in Implicit Processing of Sexual Stimuli

The present studies investigated whether men and women differ in cognitive–motivational processing of sexual stimuli in order to better understand the commonly observed gender differences in sexual outcome variables. Because these processes often operate without conscious control, we focused specifically on automatic stimulus processing. Using a series of implicit tasks, we measured inhibition, attentional orientation, appraisal and approach–avoidance motivation regarding sexually explicit stimuli in male and female students. Results showed that men were more strongly motivated to approach sexual stimuli than women and were better able to inhibit sexual information as to prevent activation of the sexual response. With regard to attentional orientation, men were more easily drawn by sexual cues than women, yet only when the cues were presented long enough to allow more elaborative processing. No gender differences were found in the implicit evaluation of sexual information, although men and women did differ at the level of self–reported sexual evaluations. Our results indicate the importance of incorporating information–processing mechanisms and emotion regulation strategies into the conceptualization of the sexual response and promote further research on the specificity, robustness, predictive validity and malleability of the cognitive–motivational processes underlying sexual arousal. Copyright © 2015 European Association of Personality Psychology

The Stroop effect at 80: The competition between stimulus control and cognitive control.

For more than 80 years, researchers have examined the interference between automatic processing of stimuli, such as the meaning of color words, on performance of a controlled-processing task such as naming the color in which words are printed. The Stroop effect and its many variations provide an ideal test platform for examining the competition between stimulus control and cognitive control of attention, as reflected in behavior. The two experiments reported here show that rhesus monkeys, like human adults, show interference from incongruous stimulus conditions in a number-Stroop task, and that the monkeys may be particularly susceptible to influence from response strength and less able, relative to human adults, of using executive attention to minimize this interference.

On the malleability of automatic attentional biases: Effects of feature-specific attention allocation

In two experiments, we examined the extent to which automatic attentional biases, as indexed by performance in the emotional Stroop task (Experiment 1) and the dot-probe task (Experiment 2), are modulated by feature-specific attention allocation. In both experiments, participants were encouraged to attend to either affective stimulus information (affective groups) or non-affective semantic stimulus information (non-affective groups). In both experiments, an attentional bias towards negative stimuli was found in the affective groups but not in the non-affective groups. In Experiment 1, we also observed an attentional bias towards non-affective semantic stimulus information in the non-affective group but not in the affective groups. We argue that these effects are due to a modulation of automatic stimulus processing by feature-specific attention allocation. Our data demonstrate that automatic attentional biases toward negative stimuli are not unconditional but instead depend on the relevance of negative information. Moreover, the results of Experiment 1 suggest that attention is automatically biased towards non-affective stimulus dimensions that are currently relevant.

Using auditory event-related EEG potentials to assess presence in virtual reality

The feeling of presence in a virtual reality (VR) is a concept without a standardized objective measurement. In the present study, we used event-related brain potentials (ERP) of the electroencephalogram (EEG) elicited by tones, which are not related to VR, as an objective indicator for the presence experience within a virtual environment. Forty participants navigated through a virtual city and rated their sensation of being in the VR (experience of presence), while hearing frequent standard tones and infrequent deviant tones, which were irrelevant for the VR task. Different ERP components elicited by the tones were compared between participants experiencing a high level of presence and participants with a low feeling of presence in the virtual city. Early ERP components, which are more linked to automatic stimulus processing, showed no correlation with presence experience. In contrast, an increased presence experience was associated with decreased late negative slow wave amplitudes, which are associated with central stimulus processing and allocation of attentional resources. This result supports the assumption that increased presence is associated with a strong allocation of attentional resources to the VR, which leads to a decrease of attentional resources available for processing VR-irrelevant stimuli. Hence, ERP components elicited by the tones are reduced. Particularly, frontal negative slow waves turned out to be accurate predictors for presence experience. Summarizing, late ERPs elicited by VR-irrelevant tones differ as a function of presence experience in VR and provide a valuable method for measuring presence in VR.

Subliminal Sexual Stimuli Facilitate Genital Response in Women

Visual sexual stimuli (VSS) are believed to undergo an automatic process of stimulus appraisal and (genital or subjective) response generation. Consistent with this belief, studies have found that subliminal VSS can facilitate responses to subsequent sexual stimulus presentations. We tested whether subliminal sexual stimuli facilitated a genital response in women and, furthermore, whether this genital response could be modulated by both opposite-sex stimuli and same-sex stimuli (i.e., whether the genital response to subliminal stimuli is category-specific or nonspecific). Twenty heterosexual women underwent vaginal photoplethysmography while being subliminally (20 ms) exposed to same-sex, opposite-sex, and nonsexual slides in a priming experiment. Vaginal pulse amplitude was increased when target stimuli were preceded by both opposite-sex and same-sex priming stimuli relative to nonsexual priming stimuli. This finding suggests that subliminal VSS were subjected to automatic stimulus processing, thereby facilitating nonspecific genital response preparation. Results are discussed in terms of implicit and explicit memory access and the evolutionary benefit of female nonspecific genital response.

Automatic affective stimulus processing is intact after unilateral resection of the anterior temporal lobe in humans

Only hundreds of milliseconds after an incoming stimulus is perceived, we make an evaluation of whether it is good or bad. This evaluation seems to occur automatically and can significantly influence behavior. According to several functional imaging studies, the amygdala, which is localized in the temporal lobes of the brain, is an important structure for the automatic processing of affective stimuli. To investigate how critical a role the amygdala plays in this process, we had 20 participants with unilateral resection of the temporal lobe and 20 controls perform an affective priming task. Both controls and patients demonstrated shorter response latencies on trials where prime and target had the same valence than on trials where prime and target had the opposite valence. This finding is generally known as the affective priming effect and is considered to reflect automatic stimulus evaluation. More specifically, it is assumed that the valence of the prime stimulus is activated automatically and exerts an influence on the speed by which the target stimulus is evaluated. Given that the affective priming effect is equally large in both groups, our results suggest that the automatic processing of stimulus valence is intact in participants who sustained unilateral resection of the temporal lobe.

ERPs reveal deficits in automatic cerebral stimulus processing in patients with NIDDM.

We compared auditory event-related potentials (ERPs) and neuropsychological test scores in nine patients with non-insulin-dependent diabetes mellitus (NIDDM) and in nine control subjects. The measures of automatic stimulus processing, habituation of auditory N100 and mismatch negativity (MMN) were impaired in patients. No differences were observed in the N2b and P3 components, which presumably reflect conscious cognitive analysis of the stimuli. A trend towards impaired performance in the Digit Span backward was found in diabetic subjects, but in the tests of secondary or long-term memory the groups were comparable. Patients with NIDDM may have defects in arousal and in the automatic ability to redirect attention, which can affect their cognitive performance.