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effect of practice cannot be explained by means of the transfer-of-training theory,

This study would only lead to strong presumptions as to which central abilities will be affected by practice. It has to be left to further investigations to find an unambiguous answer.

E X P E R I M E N T A L I N V E S T I G A T I O N S OF P R O A C T I V E

I N H I B I T I O N A N D R E C A L L

M, WASIM AND A. SUMMERF1ELD London (England)

There is increasing evidence that proactive interference contributes to forgetting (1, 2). Overiearning of one kind or another is a feature of much ordinary learning but has not received a lot of attention in experimental studies. The object of the investigations which are discussed was to examine effects of repeated learning and overlearning on recall; and, in particular, to test the results of other investigations: (a) that repeated learning of similar materials leads to poorer recall, owing to proactive interference, but that impairment of recall does not extend to relearning, (b) that positive transfer in learning continues under these conditions.

Two related experiments were carried out. In each expe.rimcnt sub- jects learned a new serial lean)ing task at the same time each day on four successive days. Retention was tested by recall and relearning either 4 or 20 hours after learning. In the first experiment learning each day was to a criterion of bare mastery (one perfect trial) or of uverlearning (50% more trials than for mastery). On the first day of the second experiment half the subjects learned to bare mastery and half overlearn- ing by 5 0 % ; on subsequent days subjects learned new tasks for the same number of trials as on the first day, so they were in fact subjected to increasing amounts of overlearning. In previou s investigations the same subjects have often learned under several di~terent conditions of overlearaing and retention. In these investigations each subject belonged to only one condition of overlearning and retention since cumulative effects were themselves being studied.

Results. (a) Recall after 20 hours was progressively worse from day to day when learning had been to bare mastery; recall after 4 hours showed the same trend, but less reliably so. (b) �9 reversed

352 THEMA 8

this trend for recall over the shorter, 4 hour interval; it was less elrec- tive over tile longer, 20 hour interval and mo;e tban 50% overlearning had an adverse effect. (c) Relearning improved from day to day and as a result of overlearning, except that the most massive amount of overlearning in the second experiment produced some deterioration. (d) All measures of retention showed bet terretent ion after 20 hours than after 4 hours. (e) There was cumulative positive transfer in learning from day to day under ,all conditions, but positive transfer was reduced by the most massive amounts of overlearning in the second experiment.

Similar results have been reported by other investigators, except for the effects of overlearning which have not previously been examined in this way. Interpreted in terms of interference, the results suggest that overlearning (i) reduces intraserial interference or inhibition, which also decreases over time, (ii) increases proactive interference or inhibition which, as has previously been suggested (1), increases over time.

REFERENCES

1. UbrOERWOOD, B. J., P.rychd. Rev., 1957, 64, 49-60. 2. - - - and POSTM^r~, L., Psychol. Rev., 1960, 67, 73-95.

L E A R N I N G D U R I N G A " L E C F U R E " .

E X P E R I M E N T A L I D E N T I F I C A T I O N OF SOME V A R I A B L E S

SUMAYA A. FAHMY Cairo (Egypt)

This study is an attempt to define and isolate some variables in the teaching situation known as the "lecture" method, and ~o investigate the effects of each on the recall of information contained in the lecture. These probable variables are: (1) Writing the lecture; (2) Listening to the lecture; (3) Alternate listening and summarizing.

EXPERIMENT I

99 female students of Education from Ein-Sharns University, Cairo, between the ages 20-23 years, taking introductory Psychology, were divided at random into three groups. The experiment was conducted on each group separately. For all groups: The material of the lecture was a prose passage on a topic in Psycholo~gy; mode of presentation was reading passage by E (author) in a speaking manner; the period of presenting material and the