Claparède performed a fairly well known experiment in which he would test whether or not the trauma of a painful event would be retained if short term memory was lost. His experiment involved a woman who suffered from a form of amnesia. She had all of her old memories as well as her basic reasoning skills, but the recent past was not remembered. Claparède had greeted her every day, each time she could not remember his face at all. Then during one session of the experiment, Claparède hid a pin in his hand and reached to shake the woman's hand, pricking her. The next day, sure enough, she did not remember him. But when Claparède went to shake her hand, he found that she hesitated, recognizing a threat when her memory had been severely damaged.