Fogetting And Retention

Retention and Forgetting 1

Factors affecting forgetting/retention • Time (decay theory) • Interference -> the majority of this research is based on explicit memory • Strength of original learning • Acquisition Schedules • Acquisition Variability • Acquisition Feedback 2

Time Theory • Popular forgetting functions • Y = memory strength • T = time • b = forgetting • a = some initial memory strength 3

Time Theory Functions Linear Function: does not ﬁt well with most forgetting Y = a - bT rate of forgetting is constant over time. Exponential Function: is based on physical decay, does not ﬁt forgetting well Y = ae-bT forgetting slows as a function of memory strength over time Exponential Power Function (1-c) Y = ae-bT Wickelgren - “c” approximates .75 for most forgetting data. Fits Wickelgren’s data well Logarithmic Functions Y = a - b(logT) Ebbinghaus = rate of forgetting slows w/Time Fits data very well Power Function -b Y =aT rate of forgetting declines w/Time. Fits Ebbinghaus data even better 4

Woltz Study 5

Woltz Study • With short intervals (up to 90 minutes) the logarithmic, exponential-power, and power-forgetting funcitons ﬁt the data almost equally as well 5

Woltz Study • With short intervals (up to 90 minutes) the logarithmic, exponential-power, and power-forgetting funcitons ﬁt the data almost equally as well • on delayed intervals, the exponential and exponential power functions were both poor ﬁts eight days later (after learning). Both of these functions overestimated the amount of forgetting compared to the data. 5

Woltz Study • With short intervals (up to 90 minutes) the logarithmic, exponential-power, and power-forgetting funcitons fit the data almost equally as well • on delayed intervals, the exponential and exponential power functions were both poor fits eight days later (after learning). Both of these functions overestimated the amount of forgetting compared to the data. • The power function was within the 95% confidence interval in latency means. 5

Woltz Study • With short intervals (up to 90 minutes) the logarithmic, exponential-power, and power-forgetting funcitons fit the data almost equally as well • on delayed intervals, the exponential and exponential power functions were both poor fits eight days later (after learning). Both of these functions overestimated the amount of forgetting compared to the data. • The power function was within the 95% confidence interval in latency means. • BTW, this was implicit memory data 5

Interference • Is there interference in implicit memory? • Graf & Schacter (1987): the critical manipulation involved an AB, AC interference paradigm. Interference condition subjects required to study a list of target words (e.g., shirt - window) that had the same stimuli (or A words) as the interference pairs (e.g., shirt - ﬁnger). • Under the control conditions, the target and interference lists had no words in common. (AB, CD lists) • Proactive: AB lists before interference list; Retroactive: AB lists after interference list • cued recall and completion: ( shirt - win_____) • same ( shirt - win_____) vs. different (bottle - win___) 6

Interference • Is there interference in implicit memory? • Same vs. different manipulation: if recall and completion are based solely on memory for individual B words, type of context should not affect performance. However, if recall and completion are based on associative memory for word pairs, performance should be higher in the same condition. 7

Interference • Is there interference in implicit memory? • Same vs. different manipulation: if recall and completion are based solely on memory for individual B words, type of context should not affect performance. However, if recall and completion are based on associative memory for word pairs, performance should be higher in the same condition. • no interference in the fragment completion (implicit) but interference did occur in the cued recall (explicit). Is it the explicit act of recall that causes interference? does this imply different memory systems? 8

Strength of learning • Slamecka: most people believed better the initial learning, the slower that memory fades. Slamecka provided evidence this may not be the case. Rate of forgetting does not necessarily depend on initial learning. Level of processing and type of encoding do have an effect on initial learning but so do motivation and attention. 9

Acquisition Schedule Spacing • Expanding the rehearsal schedule such that as much time is allowed to go by before the repetition of the learning event is repeated and yet still allow for successful retrieval. • Both implicit and explicit memory are affected by spacing. 10

Acquisition Variability • more variability equals better retention but slower initial acquisition • general vs. speciﬁc transfer • more elaborate memories • Things that improve retention also promote transfere • frequent, speciﬁc and immediate feedback (that’s troublesome is it not?) 11

• retrieval induced forgetting--losing some information based on the retrieval of other information. 12

Fogetting And Retention

by fazel10 on Mar 31, 2009

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Fogetting And Retention — Presentation Transcript