MEMORY IN THE BRAIN

The single most well-known person in the history of the neuroscientific study of memory was not a scholar but a patient: Henry Gustav Molaison (1926–2008), known from the literature as H.M. (Carey 2008; Eichenbaum 2012: 87–92; Squire & Kandel 1999: 11–4). In 1953, in an attempt to relieve his severe epilepsy, a part of H.M.'s brain was removed, including his hip-pocampus (Figure 4.1). From the day of his operation, H.M. forgot new events as soon as they happened. Whenever psychologist Brenda Miller entered his room for the forty years during which they worked together, H.M. failed to recognize her. As years went on, he could not recognize himself on a photo, because he was not able to make memories of his own changing appearance. At the same time, he did not lose his memories from the time well before the operation and retained his cognitive abilities. In order to remember new pieces of information (such as numbers or words) he performed various mental manipulations, but he eventually forgot them after a few minutes. His favorite pastime was to solve difficult crossword puzzles. Remarkably, although he was unable to memorize events or faces, he was able to learn new skills, such as drawing a figure by looking at its reflection in a mirror.

Cognitive psychologists traditionally distinguish three stages involved in learning and memory: encoding, storage, and retrieval (Eysenck 2004: 291).