Abstract: Behavioral inhibition and uninhibition is one of the most important dimensions of temperament which influences individual's personality and social development. Laboratory observation which included three strange situations were adopted. 122 subjects around 2-year-old (aged from 21 to 27 months), were randomly selected from Beijing residents. The results showed : (1) The behavioral inhibition and uninhibition toddlers constituted the extreme 20% and 10% from each end of the distribution respectively: (2) Inhibited and uninhibited behaviors were consistently shown across different strange situations.

Key words: two-year-old toddlers, behavioral inhibition, behavioral uninhibition