Visual statistical learning has been established as a paradigm for testing implicit knowledge that accumulates gradually with experience. Typically, subjects are presented with a stream of scenes composed of simple shapes arranged according to co-occurrence rules. Subjects observe the scenes without a defined task, and during the test subjects’ familiarity with the building blocks of the scenes is measured. However, the test in this paradigm usually directly follows the practice, while long-term effects are usually considered to last for hours or days. In addition, while the learning is implicit, the underlying structure of scenes can be summarized by a few explicit rules, which when told to the subject, the task becomes trivial. It is not clear, however, whether the implicit learning leads to explicit knowledge of the rules, or if the two types of learning are unrelated. To address these issues, we ran a modified visual statistical learning study, where subjects were tested one hour after the practice session. In addition, we varied the length of practice from 144 to 216 to 288 scenes. At short length, subjects showed no learning (55%, p>.05), in strong contrast with earlier results (74.7%, p<0.0001) where the practice and test without intermission yielded strong implicit learning. As the length of practice increased to 216, implicit familiarity emerged (82%, p<0.004), whereas with 288 trials not only did performance improve further (85%, p<0.0004), but explicit knowledge of the rules was reported by a majority of the subjects. Thus, even though visual statistical learning contributes to immediate familiarity, it is also the basis of more prolonged representations in long term memory. Moreover, this type of learning gradually leads to the emergence of explicit knowledge of the rules observed in the scenes, thus questioning the idea that implicit statistical and explicit rule learning are two separate processes.

Leave a Reply

Your email address will not be published. Required fields are marked *