關鍵詞：自主和非自主抑制；認知老化；反應時間分布分析 ;Inhibition is a core executive function and can be theoretically categorized into voluntary and involuntary. Whereas voluntary inhibition requires conscious process and active suppression, involuntary inhibition proceeds unconsciously and cannot be actively initiated. The aims of the current study were to assess the age difference and relationship between voluntary and involuntary inhibition across age groups. All participants (young: 21.9±1.14 yrs, N= 41; elderly: 66±5.45 yrs, N= 41) completed voluntary (Stop Signal and Go/NoGo) and involuntary (Negative Priming and Inhibition of Return) tasks. The results revealed that the young group had shorter stop-signal RT and larger difference between go-go and nogo-go RT, indicating stronger manifestation of voluntary inhibitory mechanism. In contrast, there was no significant difference between age groups in NP and IOR effects. In addition, the results of the correlations across inhibitory effects of all inhibitory tasks showed weak correlation between voluntary and involuntary tasks in the young but no correlation in the elderly group. Further analysis on RT distributions revealed that the elderly group showed slower central tendency, larger variance, and higher extent of right-tailedness than the young group. Taken together, the results suggested that voluntary inhibition is more sensitive to aging than involuntary inhibition, and raised questions about the scope of the de-differentiation theory of cognitive aging.
Keywords: voluntary and involuntary inhibition; cognitive aging; distribution analysis of reaction time