Lesson 3 of 6 · Why checking makes it louder
And it does something worse than that
Checking does not only fail to settle the doubt. It wears away the very thing you were checking with.
Researchers had people check a set of gas hobs over and over. Their memory did not get more accurate. Their confidence in their memory fell, and the memory itself became less vivid and less detailed the more they checked.
Read that twice, because it is the whole mechanism. The more carefully you check, the less you trust what you saw. Which makes you check.
What the research says
In the original experiment, checking the same thing over and over left accuracy untouched but made the memory less confident, less vivid and less detailed. Checking manufactures the doubt it is meant to settle.
The original experiment. Repeatedly checking the same thing left accuracy untouched and lowered confidence in the memory, along with its vividness and its detail. Checking manufactures the doubt it is meant to settle.
van den Hout M, Kindt M (2003). Repeated checking causes memory distrust. Behaviour Research and Therapy, 41(3), 301 to 316 doi
After repeated checking the memory shifts from something you actually recollect to something you merely know. That is why it stops feeling like proof, however many times you look.
The companion paper, on what changes in the memory. After repeated checking the memory shifts from something you recollect to something you merely know, which is why it stops feeling like proof.
van den Hout M, Kindt M (2003). Phenomenological validity of an OCD-memory model and the remember or know distinction. Behaviour Research and Therapy, 41(3), 369 to 378 doi
The model behind those experiments: checking is driven by an inflated sense of being responsible for harm, and each check erodes the very confidence that would have ended it.
The account these experiments were built to test. Checking is driven by an inflated sense of responsibility for harm, and each check erodes the confidence that would have ended it.
Rachman S (2002). A cognitive theory of compulsive checking. Behaviour Research and Therapy, 40(6), 625 to 639 doi