正性情绪诱导下的自我参照加工:来自ERPs的证据

The Influence of Positive Emotion on the Degree Effect in Self-referential Processes:Evidence from ERPs

采用事件相关电位考察正性情绪对自我参照加工程度效应的影响。实验采用图片启动范式,先呈现情绪图片,然后再呈现自我参照刺激。实验发现,在P2上,中性情绪条件比正性情绪条件激发了更大的波幅,高自我相关的刺激比其它刺激诱发了更短的P2潜伏期;在N2上,高自我相关名字比中等自我相关名字和非自我相关名字诱发了更小的N2的波幅和更长潜伏期;在P3上,高自我相关名字比中等自我相关名字和非自我相关名字诱发了更大的P3波幅,中等自我相关名字比非自我相关名字诱发了更大的P3波幅。实验结果表明,人类大脑对正性情绪刺激的加工可能是不敏感的。无论在正性情绪启动还是中性启动的影响下,自我参照加工都能展现出稳定的特征,而且高自我相关的刺激会得到更为深入和精细的加工,表现出自我参照加工的程度效应。

Self-reference effect refers to the accelerated process and better memorization by the individual when the information is involved with self-concept. However, previous studies have focused only on categorical differences, considering self-relevant effects as behavioral or neural activation differences between self-relevant and non-self-relevant stimuli. Thus, they failed to take into account the degree of self-relevance. In real-life situations, different correlations usually lead to various personal meanings, as the process of highly self-relevant stimulus has a more significant physical and social meaning than that of the minimally one. In addition, there are researches showing that self-relevant information is associated with positive emotional valence, that the individual inclines to attribute positive results and traits to personal characteristics and accounts the negative results or traits unrelated with their own personal characteristics. Therefore, investigating the influence of positive emotion on self-reference process is of great value. 〈br〉 We adopted picture-priming paradigm, presented emotional pictures and self-reference stimulus with participants. To be specific, each trial was initiated by a cross appearing at the centre of the screen for 200ms followed by a blank screen whose duration varied randomly from 500 ms to 1000 ms. Then a picture from one of the two emotional pictures categories was presented for 500 ms along with black screen lasting randomly for 150~300 ms in sequence. Afterwards, 500 ms self-reference stimulus and 1000 ms black screen emerged. Subjects were instructed to identify the color of self-referential stimulus as fast and accurate as possible. If the color is blue, press the “1” key; if it is green, press the “2” key. Stimulus words would disappear after a key＆amp;nbsp;press or automatically disappear after 1000ms. After the exercise experiment, the formal experiment concluded 360 trials divided into 3 blocks. 〈br〉 Results of ERP showed that under positive emotional priming condition, the target stimulus elicited smaller P2 amplitudes than neutral condition, and highly self-relevant stimulus elicited a shorter P2 latency than any other stimulus. Furthermore, highly self-relevant names elicited larger N2 amplitude than moderately and non-self-relevant names, and under neutral priming condition, the target stimulus elicited longer N2 latency than positive emotional priming condition in frontal sites; highly self-relevant stimulus elicited longer N2 latency than any other stimulus conditions in the frontal and parietal sites. In the average amplitude of P3, highly self-relevant names elicited larger P3 amplitude than moderately and non-self-relevant names, and moderately self-relevant names elicited larger P3 amplitude than non-self-relevant names. 〈br〉 Our results indicate human brain might not be sensitive on the processing of positive emotional stimulus. Self-referential processing demonstrates stability characteristics no matter whether in positive or neutral condition. Moreover, highly self-referential stimuli receive a more thorough and elaborate procession, with a representation of degree effect of self-referential processing.