Dinkar Sharma

Intrusive Cognitions: An Investigation of the Emotional Stroop Task

The role of intrusive cognitions was investigated using the emotional Stroop effect, in which irrelevant threat-related words interfered more with color naming than neutral words. In Experiment 1, the emotional Stroop effect decreased over blocks, indicating habituation. In Experiment 2, the interference persisted when different words were used in each block, suggesting that the habituation occurred at the level of the individual stimulus. However, there was some evidence for a decline in interference, suggesting some category-based habituation. In Experiment 3, the interference continued for emotional words relative to neutral words even when the neutral stimuli formed a category. In Experiment 4, neutral words were contrasted with positive and negative words; interference occurred only for the negative words. This result undermines alternative interpretations in terms of emotionality or self-relevance and highlights the critical role of threat.

Reversing the emotional Stroop effect reveals that it is not what it seems: the role of fast and slow components.

The relative contributions of slow and fast (online) components in a modified emotional Stroop task were evaluated. The slow component, neglected in previous research, was shown to lead to the prediction of a reversed emotional intrusion effect using pseudorandomly mixed negative and neutral stimuli. This prediction was supported in Experiments 1 and 2. In Experiments 3 and 4, a new paradigm was developed that allowed a more direct observation of the nature of disruptive effects from negative stimuli. The results provided a clear demonstration of the presence of the slow component. The fast component, which has generally been assumed to be the source of the interference, was shown, in fact, to have little or no role in the disruption.

The Role of Fear-Relevant Stimuli in Visual Search: A Comparison of Phylogenetic and Ontogenetic Stimuli

It has been argued that phylogenetic fear-relevant stimuli elicit preattentive capture of attention. To distinguish between fear relevance and time of appearance in evolutionary history, the authors compare phylogenetic and ontogenetic fear-relevant and fear-irrelevant stimuli in a visual search task. The authors found no evidence for a special role of phylogenetic fear-relevant stimuli; it seems that fear relevance in general is more important than is the evolutionary age. The pattern of results indicates that attention toward threatening stimuli is mainly affected by a late component that prolongs the disengagement of attention.

Emotional activation in the first and second language

Late Finnish–English bilinguals were presented with neutral, positive, negative and taboo words in a modified Stroop paradigm in both Finnish and English. Significant interference from negative and taboo words compared to neutral words was found in both languages, whereas positive words were not found to differ significantly from neutral words. Furthermore, no differences in the size of the interference were present between languages. This suggests that, for late bilinguals with good knowledge of their second language, the first (L1) and second (L2) language are equally capable of activating the emotional response to word stimuli representing threat, and thus interfering with the cognitive processes involved in responding to colour. This effect was equivalent for negative and taboo words.

The role of time pressure on the emotional Stroop task

Although a wide range of methodologies have been employed in examining the emotional Stroop effect, little systematic investigation of these experimental manipulations has taken place. Two experiments were designed to investigate the role of time pressure in the emotional Stroop effect. It is shown that time pressure has an important role to play in determining not only the magnitude of the effect but also in whether it is possible to observe any effect at all.

Differential components of the manual and vocal Stroop tasks

In this study, four components of the Stroop effect were examined for manual word and vocal responses. The components were lexical, semantic relatedness, semantic relevance, and response set membership. The results showed that all four components were present in the vocal response task. However, in the manual word response task, the only component that produced significant interference on its own was response set membership. These results do not support predictions made by recent translation models (see W. R. Glaser & M. O. Glaser [1989] and Sugg & McDonald [1994]). A possible solution was suggested that located two sites for Stroop interference. The lexical, semantic relatedness, and semantic relevance effects were located in the lexical system, whereas the response set membership effect was located at a response selection stage.

Orienting to exogenous cues and attentional bias to affective pictures reflect separate processes

On the basis of psychophysiological research it has been argued that pleasant and unpleasant pictures inhibit orienting to abrupt startle stimuli. Converging psychophysical evidence was sought for this finding using a modified version of the spatial precueing paradigm (Posner, 1980). Specifically, exogenous cues were presented to the left and right of neutral, pleasant and unpleasant picture stimuli. In contrast to the experimental hypothesis, pleasant and unpleasant pictures failed to affect attention to exogenous cues despite slowing overall reaction times in comparison to neutral pictures. This null finding was replicated in a further experiment where rate arousal was varied within the pleasant and unpleasant picture groups. However, unpleasant pictures produced more task interference than pleasant pictures and highly arousing pictures produced more interference than pictures rated low in arousal.

The addiction Stroop task: examining the fast and slow effects of smoking and marijuana-related cues

Abstract Research has shown that attentional bias toward smoking-related stimuli is related to the maintenance of smoking behaviour and the chance of a relapse during a quit attempt. Effects of smoking attentional bias can occur both during smoking stimulus presentation (fast effect) and on stimuli that immediately follow smoking stimuli (slow effect). The current research builds on these findings by closely examining the temporal aspects of these fast and slow effects across groups of different smoking status. In Experiment 1 (n = 64), smokers, smokers attempting to quit (SATQ) and non-smokers completed an addiction Stroop task using smoking related, negative emotion and neutral stimuli. In Experiment 2 (n = 32), marijuana smokers and non-marijuana smokers completed an addiction Stroop task using marijuana and neutral stimuli. Results showed fast effects across all smoking groups (except non-smokers) and slow effects in SATQ and marijuana smokers. Furthermore, marijuana smokers showed slow effects over extended periods of time. Results also show a relationship between anxiety, nicotine dependence and attentional bias in SATQ. The implications of these findings are discussed.

Exploring the temporal dynamics of social facilitation in the Stroop task

The importance of social context in affecting attention has recently been highlighted by the finding that the presence of a passive, nonevaluative confederate can improve selective attention. The underlying mechanism, however, remains unclear. In this paper, we argue that social facilitation can be caused by distractor inhibition. Two distinct sources of evidence are provided from an experiment employing the Stroop task with and without social presence. First, analysis of the response time (RT) distribution indicates that interference is reduced at relatively long RTs. This is consistent with an inhibitory mechanism, whose effects build up slowly. Further support is provided by showing that social facilitation is prevented by using short response-to-stimulus intervals that are thought to reduce cognitive control processes.

Strategic regulation of cognitive control by emotional salience: A neural network model

We present a neural network model of stimulus processing, which uses a mechanism of adaptive attentional control to regulate the moment to moment deployment of attention according to both the demands of the current task, and the demands of emotionally salient information. This mechanism allows negative emotional information to reduce cognitive control to aid in the detection of threats, which produces a momentary withdrawal from the current task set to allow unbiased processing of available information. The combination of cognitive and emotional regulation of task set allows this model to address inter-trial aspects of emotional interference in colour naming. In particular, we focus on the nature of the emotional interference in colour naming (McKenna & Sharma, 2004) as well as in word reading (Algom, Chajut, & Lev, 2004) and show how this form of interference is functionally distinct from the classic Stroop effect. Our model addresses a range of findings in colour naming and word reading tasks and is informed by recent neuroimaging data concerning the interaction between the anterior cingulate and prefrontal cortices. The model is used to explore the interface between cognition and emotion with a series of predictions, including a qualitative distinction between state and trait forms of anxiety.