ABSTRACT
This chapter begins with a dual hypothesis about amnesic Ss, first that they have normal short term memory (STM), and secondly that they have impaired long-term memory (LTM). There has in recent years been considerable controversy over the question of whether STM, retention of items over a period of seconds, and LTM, retention of items over longer intervals, are explicable in terms of a single unitary memory system. Free-recall performance presents no difficulties since the amnesic patients were normal on the labile short-term component but impaired on the more stable long-term component. For paired-associate recall Peterson's evidence for two components would predict impaired performance for amnesic Ss at longer delays, at which point the forgetting curves should have reached asymptote. Short-term forgetting curves for amnesic and normal Ss reach asymptote at the same point, and amnesic Ss appear to show a Hebb effect. In conclusion, our results show that amnesic patients combine intact STM with grossly defective LTM.
