Assessing implicit learning with indirect tests: Determining what is learned about sequence structure.

These studies investigated the unconfounding of learning of simple frequency information from complex structure during sequenced serial reaction time (RT) trials. Experiment 1 demonstrated that disruptions in RTs that occur when Ss are transferred to random trials (e.g., A. Cohen, R. Ivry, & S. W. Keele, 1990) may result from a change in simple frequency information. The implication is that negative transfer effects cannot be attributed to the learning of complex information if simpler information is also allowed to vary between training and transfer trials. Experiment 2 used a procedure in which simple frequency information remained constant between training and transfer trials, which provided evidence of complex sequence structure learning while subjects were engaged in a secondary tone-counting task