The neural substrates of the self-prioritisation effect : the role of familiarity and emotionality : PhD thesis

Żochowska, Anna

The neural substrates of the self-prioritisation effect : the role of familiarity and emotionality : PhD thesis

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Title: The neural substrates of the self-prioritisation effect : the role of familiarity and emotionality : PhD thesis

Abstract:

The volume of information flowing in from the world is enormous and overwhelming. Yet, individuals may not be constantly aware of this, as they do not permanently experience the consequences of this immense influx of information. This is primarily attributed to the selection process, which is not always contingent on conscious choices. One possible criterion for the selection of information is its association with the self, leading to more efficient processing. This effect is called the self-prioritisation effect (SPE). Although SPE is observed in many different contexts, the factors driving this phenomenon are still ambiguous. Scientists propound two factors, familiarity and emotionality, focusing mainly on the former. In this thesis, using electrophysiological techniques, I aimed to investigate the role of these two factors independently. The first two studies were devoted to the emotionality factor. As emotions might be perceived objectively or subjectively, this distinction was transferred to the emotionality factor. In the first study, a plausible role of objective emotionality was investigated by comparing the processing of one’s own face and emotional unknown faces. ERPs analysis (with P3 and LPP in the focus of attention) and cluster-based permutation tests revealed that the processing of the self-face is unique and does not resemble the processing of the objectively emotional faces. In the follow-up study, subjective emotionality was in the spotlight. To assess its impact on the SPE, a face of a close person was introduced into the study. Such a person presents a similar combination of familiarity and emotionality factors as is possessed by the self; thus, the face of a close-other seems to be the best comparison to the self-face. Moreover, as the COVID-19 pandemic significantly impacted human lives in the last few years, the study's goals were expanded, and the SPE was tested for partial facial information. Source analysis indicated that the processing of partially covered faces is associated with the brain area typically linked to the face processing, fusiform gyrus. Amplitudes of early (P1) and late (P3, LPP) ERP components consistently indicated that all covered faces require more attentional resources to be processed, and SPE is not impoverished by the surgical-like masks, as the self-face in both conditions (with and without mask) evoked significantly higher P3 and LPP amplitudes. Furthermore, a significant difference between the processing of the self-face and the close-other’s face was depicted. This pattern of results undermines the plausible role of subjective emotionality, and in combination with findings from the first study, it deflates the role of emotionality in general. The last study was dedicated to the familiarity factor. The familiarity of the presented stimuli was equalised to disentangle the mutual impact of both factors. Apart from the highly familiar stimuli as one’s own and close-other’s faces, we used unknown abstract shapes assigned to the participant and freely chosen close-other. Our findings revealed no differences in the processing of newly acquired information (similar P3 and LPP amplitudes in both cases). As the typical pattern of face processing was manifested (larger P3 and LPP for the self-face), the lack of differences between the self-assigned shape and the shape assigned to the close-other might be interpreted as a further substantial argument in favour of familiarity as a driving factor of self-prioritisation. The findings presented in this thesis indicate that familiarity is a driving factor in the SPE. Through various paradigms and diverse analytical techniques, we have demonstrated that high familiarity of self-related information is crucial for the self-prioritisation effect. By shedding light on the intricate interplay between familiarity and emotionality, my work contributes to a deeper understanding of how individuals process information and make decisions based on SPE.