1. Trace Decay Trace decay The theory suggests that learning causes a physical change in the neural network of the memory system, creating a memory trace or “engram” The theory suggests that learning causes a physical change in the neural network of the memory system, creating a memory trace or “engram” Hebb (1949) looked at the brain and showed that a memory occurs when a group of nerve cells excite (stimulate) one another Hebb (1949) looked at the brain and showed that a memory occurs when a group of nerve cells excite (stimulate) one another

2. engramengram nounnoun a postulated biochemical change (presumably in neural tissue) that represents a memorya postulated biochemical change (presumably in neural tissue) that represents a memory Engram = biochemical change (presumably in neural tissue) that represents a memory

3. Once this memory trace has been created, it must be reinforced through repetition to strengthen it If the trace is not reinforced by practice it will simply weaken and decay, causing forgetting to occur. We need to use it or lose it!

4. Trace Decay (STM)

6. So, trace decay explains forgetting as a problem of availability – that is, the information is lost completely from the memory system through disuse and passage of time Biological processes in the brain cause the trace to decay until eventually the message it carried, is lost

8. Trace Decay Experiment Ethics This experiment aims to investigate one aspect of memory. This experiment aims to investigate one aspect of memory. You do not have to participate. You do not have to participate. You may withdraw at any time. You may withdraw at any time.

9. Trace decay You will see a trigram card After this you will be asked to count backwards from 50 in 3’s Ready…..

10. FHT

11. Count

12. Recall

13. KLB

14. Count

15. Recall

16. MCF

17. Count

18. Recall

19. HYC

20. Count

21. Recall

22. DJR

23. Count

24. Recall

25. MCG

26. Count

27. Recall

28. PDC

29. Count

30. Recall

31. PSF

32. Count

34. KCB

35. Count

36. Recall

37. HSJ

38. Count

39. Recall

41. Supporting Evidence for Trace Decay Theory Peterson & Peterson (1959) Had participants recall trigrams after varying intervals Had participants recall trigrams after varying intervals During rehearsal an Interference task was given (counting backwards in threes) to prevent rehearsal During rehearsal an Interference task was given (counting backwards in threes) to prevent rehearsal They found less that 10% of information was recalled after 18 seconds They found less that 10% of information was recalled after 18 seconds This is evidence for trace decay in STM. Participants weren’t able to practice/repeat the information/memory, and so the memory traces decayed This is evidence for trace decay in STM. Participants weren’t able to practice/repeat the information/memory, and so the memory traces decayed-

42. Evaluation However, a weakness of this research is that it was conducted in a laboratory. Consequently, the experiment involved artificial tasks (lacked --------------------------) and an unnatural setting, and therefore (lacked________________) So the results may not be valid in the “real world”, and therefore this study cannot easily be generalised to how we use memory in the real world.

43. Evaluating the trace decay theory of forgetting – AO2 -One problem is the theory is limited. There are things that it cannot explain. The problem is that we do recall things we have not thought about for a long time. For example we can ride a bike after a long period. We have not been renewing the physical memories in the meantime, but the memory is still there.

44. Sometimes, after being presented the appropriate cues, memories are triggered and long-forgotten memories remembered This suggests the engram did not decay

45. -Many elderly people can recall incidents from their youth in great detail. Unless they have recalled the instance many times throughout their lives, the trace should have decayed according to trace decay theory. -If the trace decay theory is correct, and you hadn’t played the guitar for 20 years then not only would you be unable to recall the chord sequence for a particular song, but it would also take you as long to learn the song the second time as it did the first. This simply isn’t true. -People under hypnosis can often recall things that they haven’t thought about for years, so their traces may still be intact. -Trace decay cannot explain why some people seem to have poor recall of even recent events, while others have incredible memories going back for decades.