In P. Lewicki's (1986b) demonstration of hidden covariation detection (HCD), responses of participants were slower to faces that corresponded with a covariation encountered previously than to faces with novel covariations. This slowing contrasts with the typical finding that priming leads to faster responding and suggests that HCD is a unique type of implicit process. The authors extended Lewicki's methodology and showed that participants exposed to nonsalient covariations between hair length and personality were subsequently faster to respond to faces with those covariations than to faces without, despite lack of awareness of the critical covariations. This result confirms that people can detect subtle relationships between features of stimuli and that, as with other types of implicit cognition, this detection facilitates responding.