Abstract:

The self-reference effect is the enhanced speed and quality of processing and memorization observed with respect to information that is related to the individual’s self-concept. According to the preceding research, self-reference effect have the different with degree, and different degree of intimacy with the core self. Then, the brain on the depth of its reference treatment is different, also. Highly self-relevant stimulus will get faster response compared with minimally self stimulate in the brain. This is called the degree of self-reference processing effect. On the basis of summarizing the preceding research, this study uses the event related potential technology, through ERPs experiments investigation the degree of extroversion individuals of self-reference processing effect and neural mechanisms. Experiment adopted three kinds of classic oddball models, using an implicit way to investigate the extroversion individual self-reference processing degree effect. Used three-character non-name lexical phrases served as the standard stimulus, and a three-character non-lexical phrase served as target stimuli. Six categories of stimuli were used in a three-stimulus oddball paradigm. Three sets of self-relevant stimuli, the non-self- relevant stimulus, and two filler stimuli, served as distracters. The name of the participant was used as the highly self-relevant stimulus, the name of participant’s father as the moderately self-relevant stimulus, the name of China’s leaders the minimally self-relevant stimulus, and the name of the president of the United States, served as the non-self-relevant stimulus. All names are three Chinese characters long. Familiarity was equivalent across all sets of stimulus names. All name stimuli were made into images on a PC using Microsoft Office Picture Manager. Image size, word length, and complexity were matched across the name conditions. Experiment found that on the P2 amplitude, highly self-related stimuli induced greater P2 amplitude than other stimulation. On the latent period of P2, the electrode in the front, central, and parietal position, highly self-related to stimulate induced the short latent period than other stimulation. In N2 amplitude, highly self-related name induced larger N2 amplitude than other stimulus; comparing extroversive subjects, control group subjects of highly self-relevant names induced larger amplitude of N2 than other stimulation. On the latent period of N2, highly self-relevant stimuli in the whole brain induced the short latent period of N2, it is better than other stimulation, and the parietal position of the electrode is the shortest possible; Highly self-relevant name of two types of personality subjects induced shorter latent period of N2 than other stimulation, but control group subjects is the shortest. On average amplitude of P3, highly self-relevant stimuli in whole brain induced the P3 amplitude is bigger than other stimulation. The effect of midline brain regions is largest. Comparing extroversive subjects, control group subjects of highly self-relevant names induced larger amplitude of P3 than other stimulation. Research results show that self-reference processing with the degree of effect is actually existence, highly self-relevant stimuli will get deeper and exquisite processing than moderately and minimally self-relevant stimuli. Comparison control group individuals, introversion subject was weaker in the degree of self-reference processing effect. And in early stage, highly self-relevant stimuli of control group individuals will be faster being noticed than minimally self-related stimuli by the brain. In the late stage of cognitive, highly self-relevant stimuli will get deeper and elaborating processing.

Key words: extroverted, self-reference effect, degree effect, event-related potential, N2, P3