Radical associationism: Back to the future, or fast forward to the past?

In our commentary, we applaud Rey?s ambition to unify the fields of Hebbian, statistical, and associative learning, but speak against the radical associationist program he adopts to achieve this goal. As we point out, Rey's project faces the same obstacles that connectionists have been facing for the past three decades - demonstrating the emergence of explicit rule-based reasoning out of purely associative processing. We illustrate this point with recent work on the Perruchet effect, which shows that subjects'task performance is driven not only by associative processing, but also by explicit stimulus expectancies. In our view, current empirical evidence is insufficient to adjudicate between single- and multi-process accounts of this and many other psychological findings.