In the four empirical chapters to follow, the effects of approach and avoidance related bodily cues on cognitive control processes will be systematically investigated. The general prediction underlying this research line is that avoidance-related bodily signals enhance cognitive control relative to approach-related bodily signals. We will investigate the effects of approach-avoidance bodily cues on different cognitive control functions to corroborate our central hypothesis. Furthermore, the mechanisms that underlie performance differences resulting from approach and avoidance motor signals will be addressed (Chapter 3). Across studies, different operationalizations of approach and avoidance bodily cues are used. In part, we rely on well-established manipulations of approach and avoidance such as arm flexion and extension (Chapter 2 and Chapter 3). In Chapter 4 we will introduce forward and backward locomotion as a novel procedure to manipulate approach and avoidance. Finally, Chapter 5 examines the effects of overt head movements on cognitive control.
Chapter 2 aims at providing first evidence for the regulatory function of approach and avoidance motor actions in activating cognitive control processes. We will compare the performance of participants executing either approach or avoidance arm movements on tasks tapping into different control functions. More specifically, in Study 2.1 performance differences on a Stroop (1935) color naming task will be investigated, a task that draws on the ability to inhibit automatic response tendencies. We expect that performing an avoidance movement will significantly enhance task performance compared to performing an approach movement. In Study 2.2 we try to generalize this effect to a different executive function, task switching, which refers to the ability to shift focused attention between different tasks.
Importantly, in this study approach and avoidance motor actions are manipulated within-subjects. That is, participants alternate between approach and avoidance arm movements
while performing the task. Again, we predict that approach and avoidance movements will have a differential influence on task performance.
Chapter 3 is directed at identifying the mechanisms that underlie the performance differences resulting from approach and avoidance bodily signals. We hypothesize that approach and avoidance cues may directly regulate the mobilization of energy, such that they lead to the up- or down-regulation of cognitive functioning. More specifically, avoidance cues are predicted to boost cognitive functioning through the mobilization of cognitive resources. Approach cues, in contrast, are predicted to lower the amount of cognitive energy mobilized, resulting in poorer cognitive performance. These predictions are tested with a cognitive functioning task followed by a cognitive depletion task. To confirm our resource allocation account, performance on the cognitive functioning task should be mediated by the degree of cognitive depletion on the later task, implying that performance is dependent on the expenditure of cognitive resources. More specifically, we expect participants in the avoidance condition to display superior performance on the initial switching task compared to the approach condition, but at the same time they are predicted to be more prone to resource depletion on the second task. Notably, such a mediational effect of resource allocation would sketch a more nuanced picture of approach and avoidance bodily signals: Avoidance cues might be functional in the short run, as performance benefits from the greater immediate allocation of cognitive resources. However, in the long run performance may suffer when cognitive resources become depleted.
In Chapter 4 we turn to a novel embodied manipulation of approach and avoidance that more directly taps into the fundamental nature of these action tendencies. Prior research has mainly been directed at the effects of approach-avoidance arm movements. However, body locomotion may be argued to constitute a more ecologically valid form of approach and avoidance behavior, as individuals typically approach desired objects by stepping forward
and avoid aversive objects by stepping backward. Study 4.1 introduces forward and backward body locomotion as a novel form of manipulating approach and avoidance behavior, and investigates the effects of stepping direction on cognitive control processes. Immediately after participants stepped either in the forward (approach), backward (avoidance), or sideways (control) direction, cognitive functioning is assessed by means of a Stroop (1935) task. Study 4.1 aims at further validating the findings of the previous chapters, while at the same time establishing a new procedure with higher ecological validity.
In Chapter 5 we examine the effects of head nodding and head shaking on cognitive control processes. Head nodding constitutes the embodied expression of agreement or approval, whereas head shaking stands for disagreement or disapproval. Overt head movements can be broadly considered a form of approach and avoidance behavior, as head nodding is associated with the acquirement of desired outcomes, and head shaking with the avoidance of undesired outcomes. Moreover, the processing requirements associated with overt head shaking and nodding are similar to those associated with avoidance and approach contexts, respectively. More specifically, head shaking is indicative of an undesirable state that requires cognitive effort in order to be dissolved. Hence, this bodily signal is associated with effortful processing and the need for cognitive control. Head nodding, in contrast, is associated with beneficial, optimal conditions that do not require cognitive effort on the part of the individual. We predict that unobtrusively inducing participants to nod or shake their heads will activate the cognitive modality habitually associated with these movements.
Consequently, a period of head shaking is predicted to enhance performance on a task switching paradigm compared to a period of head nodding.
Finally, in Chapter 6 the results of the present dissertation will be summarized and integrated. Furthermore, implications of the current findings and possible directions for future research will be discussed.
Please note that each of the four empirical chapters of the present dissertation comprises a published or submitted article that can be read independently. As a consequence, some minor overlap in terms of theoretical background and methodology may be encountered.