An investigation of the modulation and underlying mechanisms of the self bias effect

The self bias effect refers to the prioritised processing of self-related information (i.e. faster RTs and higher accuracy) over information about others. This phenomenon has been widely observed across many areas of cognition such as memory, attention and perception. However, current knowledge of the self bias effect is still insufficient. This thesis utilises the perceptual matching paradigm as an experimental instrument to study the self bias effect in three main aspects. First, the impact of social experiences on self bias is examined. This thesis presents data that demonstrate the modulation of self bias as a result of three factors – cultural background, situational cues and major life developments. Comparisons of the self bias between independent and interdependent cultures reveal a difference in the self bias relative to strangers. Priming of interdependent frames of mind reduces the self bias relative to friend in people with low bias, which suggests individual differences in the magnitude of the self bias effect. The transition into motherhood, as a major life development, demonstrates a loss of the self bias effect due to maternal behaviour. Second, in the attempt to explain the robustness of the self bias effect, this thesis investigates the underlying mechanisms of self bias through parallel comparisons of self-related and reward-related stimuli using the perceptual matching task. To further explain the relationship between self and reward processes, electrophysiological responses are also examined with electroencephalogram (EEG) methods. The data demonstrate partial distinctions in the neural pathway that underlie self and reward processes. Third, social psychology methods, in addition to methods from experimental psychology, are used to study the self bias effect from another perspective. However, the data are unable to link the self bias effect with trait characteristics at this stage. This thesis contributes to current understanding of self-related processing by identifying the factors that modulate self bias and exploring the underlying mechanisms of self bias.