FORGETTING DURING SLEEP AND WAKING
Recently, several psychological experimenters have undertaken to compare the amount of forgetting which takes place during sleep and during waking. In reality, all such experiments are primarily studies of retroactive inhibition. This term may be defined as the inhibitory effect exerted upon the retention of any activity (or material) by other activities intervening between the original learning and the retention test. The existence of such inhibitory effects was first demonstrated by two German psychologists, Müller and Pilzecker,1 in 1900, but the importance of their discovery was so little realized that for 24 years the topic was relatively neglected in experimental psychology.
In 1924, however, there appeared the study of Jenkins and Dallenbach which is reviewed in this chapter. The results of their experiment were so striking as to give a new impetus to work in this field. At present, the investigation of retroactive inhibition has become one of the principal experimental problems in the psychology of retention and memory. Moreover, the phenomenon itself has been widely recognized as one of the most important causes of forgetting and, consequently, as the cause of much of our habitual failure to remember accurately the things which we have learned.
The purpose of the experiment of Jenkins and Dallenbach was "to compare the rate of forgetting during sleep and waking." Their specific incentive for undertaking this problem derived from their desire to account for certain unexplained discrepancies in some of the curves____________________