@phdthesis{Flechsenhar2019,
  author    = {Flechsenhar, Aleya Felicia},
  title     = {The Ubiquity of Social Attention - a Detailed Investigation of the Underlying Mechanisms},
  doi       = {10.25972/OPUS-18452},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184528},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {This dissertation highlights various aspects of basic social attention by choosing versatile approaches to disentangle the precise mechanisms underlying the preference to focus on other human beings. The progressive examination of different social processes contrasted with aspects of previously adopted principles of general attention. Recent research investigating eye movements during free exploration revealed a clear and robust social bias, especially for the faces of depicted human beings in a naturalistic scene. However, free viewing implies a combination of mechanisms, namely automatic attention (bottom-up), goal-driven allocation (top-down), or contextual cues and inquires consideration of overt (open exploration using the eyes) as well as covert orienting (peripheral attention without eye movement). Within the scope of this dissertation, all of these aspects have been disentangled in three studies to provide a thorough investigation of different influences on social attention mechanisms. In the first study (section 2.1), we implemented top-down manipulations targeting non-social features in a social scene to test competing resources. Interestingly, attention towards social aspects prevailed, even though this was detrimental to completing the requirements. Furthermore, the tendency of this bias was evident for overall fixation patterns, as well as fixations occurring directly after stimulus onset, suggesting sustained as well as early preferential processing of social features. Although the introduction of tasks generally changes gaze patterns, our results imply only subtle variance when stimuli are social. Concluding, this experiment indicates that attention towards social aspects remains preferential even in light of top-down demands. The second study (section 2.2) comprised of two separate experiments, one in which we investigated reflexive covert attention and another in which we tested reflexive as well as sustained overt attention for images in which a human being was unilaterally located on either the left or right half of the scene. The first experiment consisted of a modified dot-probe paradigm, in which peripheral probes were presented either congruently on the side of the social aspect, or incongruently on the non-social side. This was based on the assumption that social features would act similar to cues in traditional spatial cueing paradigms, thereby facilitating reaction times for probes presented on the social half as opposed to the non-social half. Indeed, results reflected such congruency effect. The second experiment investigated these reflexive mechanisms by monitoring eye movements and specifying the location of saccades and fixations for short as well as long presentation times. Again, we found the majority of initial saccades to be congruently directed to the social side of the stimulus. Furthermore, we replicated findings for sustained attention processes with highest fixation densities for the head region of the displayed human being. The third study (section 2.3), tackled the other mechanism proposed in the attention dichotomy, the bottom-up influence. Specifically, we reduced the available contextual information of a scene by using a gaze-contingent display, in which only the currently fixated regions would be visible to the viewer, while the remaining image would remain masked. Thereby, participants had to voluntarily change their gaze in order to explore the stimulus. First, results revealed a replication of a social bias in free-viewing displays. Second, the preference to select social features was also evident in gaze-contingent displays. Third, we find higher recurrent gaze patterns for social images compared to non-social ones for both viewing modalities. Taken together, these findings imply a top-down driven preference for social features largely independent of contextual information. Importantly, for all experiments, we took saliency predictions of different computational algorithms into consideration to ensure that the observed social bias was not a result of high physical saliency within these areas. For our second experiment, we even reduced the stimulus set to those images, which yielded lower mean and peak saliency for the side of the stimulus containing the social information, while considering algorithms based on low-level features, as well as pre-trained high-level features incorporated in deep learning algorithms. Our experiments offer new insights into single attentional mechanisms with regard to static social naturalistic scenes and enable a further understanding of basic social processing, contrasting from that of non-social attention. The replicability and consistency of our findings across experiments speaks for a robust effect, attributing social attention an exceptional role within the general attention construct, not only behaviorally, but potentially also on a neuronal level and further allowing implications for clinical populations with impaired social functioning.},
  subject      = {Aufmerksamkeit},
  language  = {en}
}