To explore how the sentence contexts affect self-positivity bias, we presented the participants with negation and affirmation sentences. Each sentence was ended with an adjective word describing human being's personality. The participants were asked to judge whether the sentences correctly described their own personalities. In affirmation sentences, the behavioral data showed that self-positivity bias occurred when participants considered the sentences to be in accordance with their personality; the ERP data showed that P200 amplitude was consistent with this behavioral result. In negation sentences, behavioral data showed self-positivity bias, regardless of whether the sentences were in accordance with participants' personality or not. However, the self-positivity bias was not observed in the ERP results from negation sentence. In summary, sentence type modulated the effect of self-positivity bias. The reason could be that processing affirmation and negation sentences requires different amount of cognitive resources.
Keywords: Affirmation; Negation; P200; Self-positivity bias.