Hidden covariation detection might be very hidden indeed

P. Lewicki and colleagues (see, e.g., P. Lewicki, T. Hill, & M. Czyzewska, 1992, for a review) have demonstrated that people can unconsciously detect and retain a nonsalient covariation embedded within presented stimuli. In 9 conceptual replications of the hidden covariation detection (HCD) paradigm, there was little evidence for HCD. In exact replications of 3 of Lewicki's studies (T. Hill, P. Lewicki, M. Czyzewska, & G. Schuller, 1990; P. Lewicki, 1986a, Experiment 6.1, 1986b, Experiment 1a; P. Lewicki, T. Hill, & I. Sasaki, 1989), only 1 yielded HCD. These results cast doubt on the generality and robustness of HCD. Candidate boundary conditions for HCD are considered on the basis of the available data.