Repeated checking induces uncertainty about future threat

Studies have shown that obsessive-compulsive (OC) -like repeated checking paradoxically increases memory uncertainty. This study tested if checking also induces uncertainty about future threat by impairing the distinction between danger and safety cues. Participants (n = 54) engaged in a simulated checking task, in which they completed two series of 19 checking trials. The experimental group checked burners on a stove and the control group checked light bulbs. Participants completed two pre-tests (before the first series of checks) and two post-tests (one after the first series of checks, the other after the second series). In these tests, they first checked the stove and answered questions about memory confidence and accuracy. Then one of two conditioned stimuli (CS; i.e., a circle) was presented. A CS+ replaced a burner that was on, and a CS- replaced a burner that had been switched off. During each CS presentation, participants rated their shock (UCS) expectancy and confidence about UCS occurrence. Next, the CS+ was followed by the UCS. Analyses showed that the first series of checks did not affect memory accuracy and UCS expectancy, but did reduce confidence about memory and about UCS occurrence in the experimental group, relative to the control group. The second series of checks did not lead to these group differences, compared to the first series. The results demonstrate that repeated checking increases uncertainty not only about memory, but also about future threat.