Abstract
Lewicki and colleagues have demonstrated that people can implicitly learn hidden covariations between elements of presented stimuli. Under conditions of tight experimental control, we obtained little evidence for such Hidden Covariation Detection (HCD) in both conceptual and exact replications of Lewicki’s studies. The results of that HCD research are summarised and reviewed in this paper. These results cast doubt on the generality and robustness of HCD and suggest that HCD is subjected to various boundary conditions. Other paradigms more easily result in implicit covariation detection and provide a good starting point for more process-related investigations into implicit covariation learning. More specifically, we investigated whether the classical conditioning phenomenon of ‘blocking’ can also be observed in implicit learning No evidence for blocking was obtained suggesting that blocking does not necessarily represent an acquisition failure but may be the result of a performance deficit. The consequences of this finding for the implicit/explicit distinction are discussed.