Neural underpinnings of preparatory processes: The roles of prediction, previous experience and social context in attentional control
Every day we perform many tasks either individually or jointly with other people (joint action) which require us to deploy attention to the targets and suppress a set of distractors which otherwise impair our task performance. There are multiple factors which might boost the salience of the irreleva...
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|Summary:||Every day we perform many tasks either individually or jointly with other people (joint action) which require us to deploy attention to the targets and suppress a set of distractors which otherwise impair our task performance. There are multiple factors which might boost the salience of the irrelevant objects, making it harder to suppress them, such as selection history (Awh, Belopolsky, & Theeuwes, 2012). On the other hand, task predictability facilitates target selection and distractor suppression via the proactive control mechanism (Braver, 2012) which engages before stimulus presentation. However, selection history influences have been shown to continue capturing attention even when participants can predict the upcoming task (Kadel, Feldmann-Wüstefeld, & Schubö, 2017). The other factors which influence the salience of an object, especially in joint action tasks, are social value and social context. Previous research has reported co-representation of the partner target by an agent (Sebanz, Knoblich, & Prinz, 2003), which is present in the cooperative context and absent in the competitive context (Hommel, Colzato, & van Den Wildenberg, 2009). There are, however, still some gaps in the literature that the present dissertation will cover. Firstly, it is not well-understood how proactive preparation is implemented in the presence of selection history. Importantly, knowledge about brain activation during task preparation and the influence of selection history on that is lacking. Secondly, the influence of the social value and social context on attentional capture and its neurophysiological mechanisms need more investigation, something that is going to be covered in the present dissertation.
The present dissertation is divided into two main parts. In the first part (Studies I – III), the core research question is whether and how task predictability modulates attentional biases induced by selection history. In the second part (Study IV), the core goal is to investigate the influence of social value and social context on attentional capture by the distractor. In the first part, to induce individual selection history, participants either categorize the color of the color singleton (color group) or the shape of the shape singleton (shape group) in a categorization task. Next, all participants perform a search task wherein a diamond-shape target has to be selected while a red circle is sometimes present. Crucially the tasks are combined with different levels of predictability (Studies I and II): In Study I the task sequence is either predictable or unpredictable, while it is always predictable in Study II, but with different degrees of reliability (high-predictable vs. low-predictable). These variations of task predictability allow for a systematic examination of the influence of proactive preparation on selection history attentional biases.
Study I demonstrated the engagement of proactive preparation when the upcoming task was predictable. This proactive preparation was reflected in reduced power of posterior pre-stimulus alpha-band, but only in predictable sequence blocks. Importantly, proactive preparation was scaled by individual selection history – the color group participants who needed more task-set reconfiguration when switching between the tasks benefitted more form task predictability and exerted stronger proactive preparation. Consequently, these participants didn’t need to exert strong stimulus-driven distractor suppression after stimulus onset. This was reflected in the amplitude of the early Pd component (a marker of early distractor suppression) which remained the same irrespective of task predictability. The shape group participants, however, had to compensate for their weaker proactive preparation before stimulus onset using an early suppression of the distractor as it was reflected in a larger early Pd amplitude in predictable than in unpredictable sequence blocks. The findings of Study I were extended in Study II wherein the task sequence was constant in a session and different between sessions. Increasing predictability was shown to have a small influence on proactive distractor suppression in the shape group, maybe because the knowledge about the target dimension was enough for optimal task performance and task predictability didn’t change the dimensional information of the target and distractor for this group. However, participants in the color group exerted a stronger early distractor suppression when task predictability was more reliable, suggesting the utilization of proactive preparation when the task requires it.
Selection history increased attentional capture by the distractor’s feature within the dimension involved in previous selections. This appeared as a distractor N2pc in the color group in Study II when the task predictability was less reliable. Proactive preparation facilitated suppression of the distractor by the color group participants as the distractor N2pc became smaller and the early Pd became larger when task predictability was more reliable. Although the color group participants had a larger benefit from task predictability, the target selection by these participants remained impaired when the color distractor was present. This impaired target selection was reflected in larger behavioral distractor costs (Studies I and II) and later onset of the target N2pc (Study I) in the color group than in the shape group. These findings demonstrate that proactive distractor suppression doesn’t have the potency to negate attentional biases induced by selection history.
The impact of the selection history on the priority map was quantitatively evaluated using an algorithmic model in Study III. The model calculated the weight of four different maps such as history, color, shape, and orientation for each group. The color group showed a very prominent weight of the history map which was larger than that of the shape group. This quantified the more reliance of the color group participants on their selection history because they needed it to accomplish the categorization task. On the other hand, the weight of the shape map was the highest in the shape group. This suggests that the shape group participants could accomplish both tasks by relying on shape discrimination and without any need to refer to their history. Importantly, the color map had a larger weight in the color group than in the shape group, explaining the larger attentional capture by the distractor in the color group than in the shape group. In sum, the model could provide quantitative measures from each map, explaining how selection history interacts with physical salience in directing attention in the priority map.
In the second part of the present dissertation (Study IV), pairs of participants shared a joint task, either cooperatively or competitively, wherein participants had to respond to their own target (agent target vs. partner target). Crucially, a color distractor which was not the target for either of the participants (non-relevant distractor) was present in some trials. Although both the partner target and the non-relevant distractor were non-targets for the agent, they captured the agent’s attention differently. While the partner target captured the agent’s attention, as reflected in a negative lateralization of parieto-occipital alpha-band power and longer response time, the non-relevant distractor was suppressed and it was reflected in a positive lateralization of parieto-occipital alpha-band power. Importantly, attentional capture by the partner target depended on the social context. While the partner target captured the agent’s attention in the cooperative condition, reflected in a negative lateralization of parieto-occipital alpha-band power, the same stimulus was suppressed in the competitive condition, as reflected in a positive lateralization of parieto-occipital alpha-band power. This indicated that participants tune their attention toward their partner target depending on the social context and the task.
In sum, the four studies completed in the present dissertation examined the influence of different factors such as previous experience, task predictability, social value and social context on attentional control. Previous experience with a feature dimension was shown to increase the salience of the stimuli in that dimension, thus increasing attentional capture. Although increasing task predictability was shown to decrease the attentional biases induced by selection history, it didn’t negate the selection history influence entirely. Further, the social value was shown to change the salience of the stimuli. The partner target captured attention while the irrelevant stimulus with similar luminance was suppressed. Attentional capture by the partner target was further shown to be a function of the social context. The present dissertation, therefore, suggests that attentional control is flexible, as distractor attentional capture can vary depending on factors such as task predictability, previous experience, social value, and social context.|
|Physical Description:||156 Pages|