Memory and Eyewitness Testimony

A. Loftus and Palmer (1974) found that post event information has a significant effect on memory. In their study they found that when people were given different adjectives to describe a car crash (hit, smashed, collided, bumped or contacted) they would respond differently; the group that were given the word smashed estimated the highest speed 41mpg. In comparison the group given the word contacted estimated the lowest speed, 30mph.

Loftus et al (1978) found that when participants were given a misleading question only 45% of participants would give the correct answer whereas when people were given a question consistent with the slide they were shown the correct answer increased with 75%.

B. One alternative to the multi store model of memory is the levels of processing model put forward by Craik and Lockhart (1972). The levels of processing model rejects that there are different stores in memory but proposes that memory is a product on how deeply something is processed. Craik and Lockhart claimed that deep processing will lead to a longer term memory and involves understanding something semantically. In contrast shallow processing will lead to a short term memory and involves non meaningful processing – such as the shape of something. Things are initially processed on a shallow level then elaborative rehearsal will lead to deep processing.

C. One explanation of forgetting in long term memory is the decay theory; this states that memory is lost due to the brain damage or through the aging process if rehearsal is prohibited; if a memory lies dormant for an extended period of time it is likely to be forgotten. Lashley (1931) found a correlation between how much material was removed from a rats brain and the amount they forgot. The more material removed the less the rat would forget. This shows strong support for the decay theory.

However, this research can be said to be lacking in validity because humans aren't rats; this experiment may explain how rats forget but as humans are more highly evolved we may forget in different ways. The decay theory also fails to show why some memories, such as flashbulb memories are very long lasting; these memories can be learnt from a very young age and still remembered; this shows that at least one other factors plays a part in forgetting in long term memory.

Baddeley and Hitch (1977) studied rugby players and how much they remembered; they found that the more games the rugby players played the more they forgot; this disproves the decay theory because if the decay theory was correct all the players would recall a similar percentage of games.

A second explanation of forgetting in long term memory is the interference theory; this states that one memory will "block" or get in the way of another theory which will prevent retrieval; there are two types of interference, proactive interference, this is where past learning interferes with current learning and retroactive interference, this is where current learning interferes with past learning.

McGeoch and McDonald (1931) asked participants to learn lists of adjectives and then carry out unrelated tasks, they found that when participants had to rest during the interval between learning and recall forgetting was least, forgetting increased when participants had to learn unrelated material during the interval and forgetting was at its maximum when they were asked to learn adjectives similar in meaning to the original list. This shows that forgetting increases when tasks are similar to the interfering material thus supporting the interference theory.

Tulving and Pstotka (1971) found evidence for retroactive interference as when participants learnt more lists the worse their performance, however, this was overcome if participants were given cues, performance was constant at 70% showing evidence for cue dependant forgetting as opposed the interference theory.

A. Baddeley (1966) tested four groups on short term memory, each hearing one of the four lists, acoustically similar, acoustically dissimilar, semantically similar or semantically dissimilar. The list was repeated 4 times and then asked to recall them in the correct order Baddeley found that participants with acoustic similarity did worst; recall for this list was 55% whereas recall for the other three lists was 75%

B. Bartlett (1932) found that when participants were given a story from a different culture and asked to recall it they would change the story to match their own culture; Bartlett found that the order would be changed and that there would be alterations in importance. He then found that over time there would be more alterations, so much so that eventually the story would resemble an English story. Bransford and Johnson (1972) also found that when participants were given the title "making and flying a kite" they had better recall of a text to a group that didn't showing that the title became a schema and helped encode the information.

C. Williams (1994) interviewed over 100 women who had attended city hospital emergency room 20 years ago for sexual assault. No direct questions were asked about sexual assault and the experiment was double blind; the interviewers and participants were told this was a follow up study of the health of women who had received medical care for the hospital during childhood. Williams found that 38% of women has no recall for the sexual abuse and of those that did recall it, 16% said that they had repressed it at some time. Abuse at an earlier age was most likely to be forgotten.

However, it can be claimed that this research lacks population validity; the findings can only be applied to poor urban women because that was the only sample; the findings cannot be generalised beyond this sample.

It can also be claimed that some of the reports were false or that some of the women wanted to avoid the subject, sexual assault is an uneasy subject. However, the most credible reports had the highest level of forgetting, supporting the repression theory. As the research was double blind it can be said to increase in validity as there would be no interviewer bias; the interviewer doesn't know what s/he's looking for so will carry out an un-bias interview. 

Hochman (1994) found that rather then memories being repressed, memories would haunt victims through Post Traumatic Stress Disorder in a study involving children whose school was attacked by a sniper; children had false memories of the event. This is evidence against repression.