Abstract: Implicit learning, after implicit memory, is becoming one of the most important research topics in the current field of cognition and learning. Using serial reaction time (SRT) paradigm, we conducted two experiments to study the mechanism of implicit learning of sequence positions. The results showed: (1) In the serial reaction time task, with the lengthening of response-stimulus interval (RST), the amount of implicit learning decreased. (2) Subjects' implicit learning score of isomorphic transfer group was almost the same with that of nonisomorphic transfer group, the subjects could not implicitly acquire the underlying abstract pattern of sequence locations. These indicated that implicit learning of sequence positions mainly depended on horizontal associations of events, not vertical associations.

Key words: implicit learning, serial reaction time (SRT) task, response-stimulus interval (RSI), horizontal associations, vertical associations