Learning complex sequences: no role for observation?

Two experiments examined performance in a sequence learning task. Participa nts were trained on a repeating sequence which was presented as a visual di splay and learning was measured via the increase in reaction time to respon d to a new sequence. Some participants made a response to each stimulus whi le others merely observed the sequence. In Experiment 1 participants respon ding to the display via a keypress showed learning, but those merely observ ing did not. Five possible reasons for the failure to find observational le arning were considered and the Experiment 2 attempted to resolve these. Thi s second experiment confirmed the findings of Experiment 1 in a non-spatial sequence display using a cover story which encouraged attention to the dis play but not rule-search strategies. The results are discussed in relation to applied and theoretical aspects of implicit learning.