Hidden covariation detection: a fundamental and ubiquitous phenomenon.

H. Hendrickx, J. De Houwer, F. Baeyens, P. Eelen, and E. Van Avermaet (1997) reported a series of (mostly unsuccessful) studies on nonconscious hidden covariation detection (HCD); for example, they reported that out of 3 attempts to replicate P. Lewicki et al.'s studies, only 1 produced the expected results. They concluded that HCD may be not as general and robust as the previous research suggested, and they considered boundary conditions. In this article, the authors discuss a number of weaknesses of H. Hendrickx et al.'s experiments (and systematic deviations from the original methodology) that are potentially responsible for the lack of the expected results and discuss missing facts in their arguments (e.g., they failed to mention any published replications of the HCD studies from other than the present authors' laboratories). It is argued that when all evidence is considered, the proper conclusion is that nonconscious processing of covariations is not only general and robust but also a ubiquitous phenomenon mediating a variety of processes of acquisition of information.