Psychology Memory Studies

Baddeley (1966) – Encoding in short and long- term memory Method: Participants were given four sets of words to recall in order. For the STM task they had to recall them immediately following presentation and for the LTM task they had to be recalled following a longer time interval. Set 1 were words that all sounded similar, for example: cat, mat, cap, map… Set 2 were words that sounded differently for example: dog, bin, cup, pen…. Set 3 were words of similar meaning for example: big, large, huge, vast… Set 4 were words of different meaning for example: huge, good, light, blue…. The researchers then recorded the how many mistakes were made in recalling the sets of words. STM: Findings In the STM procedure participants made significantly more mistakes on words that sounded alike so for example would confuse cat and cap etc. Similarly with letters, S and X would be confused as would M and N and P and B etc. Conclusion It was concluded that in STM information is encoded by its sound (acoustically) so when we recall information from STM similar sounding words get confused. LTM: Findings In the LTM procedure participants were far more likely to confuse words of similar meaning replacing huge with vast or night and dark etc. Conclusion It was concluded that in LTM information is encoded by its meaning (semantically).

Bahrick et al. (1975) – Duration of long-term memory Method: participants (ex-high-school students aged from 17 to 74) memory was tested in various ways: Free recall of names Photo recognition test from 50 photos (visual recognition) Name recognition test Name and photo matching test Findings: Face and name recognition was 90% accurate for those who had left high school 34 years previously. After 48 years, name recognition declined to 80%, face recognition decline to 40%. Free recall was 60% accurate after 15 years and 30% accurate after 48 years. Strengths: high mundane realism, testing real life memory the findings are likely to generalise to other situations Limitations classmates’ faces are likely to have emotional significance different individuals in each age group – on average, younger adults received more years of education. The differences could be due to the negative effects of age on memory, or greater length of education

Jacobs (1887) – Capacity of short-term memory Method: Participants were read lists of either words or numbers that they had to recall immediately after presentation. Jacobs gradually increased the length of these digits etc. until the participant could only accurately recall the information, in the correct order, on 50% of occasions. Recall has to be in the correct order (serial recall). Findings: Jacobs found a difference between capacity for numbers and for letters. On average participants could recall 9 numbers but only 7 letters. Strengths later studies (Miller 1956) have supported Jacobs’ findings and conclusions - the magic number seven, plus or minus two Miller and others have also discovered that chunking can increase capacity Limitations artificial stimuli was used- lacking ecological validity and mundane realism

Peterson and Peterson (1959) – Duration of short-term memory Method: Participants were presented with a trigram consisting of three random consonants, which they were then asked to recall in the correct order after a delay of 3, 6, 9, 12, 15, or 18 seconds. During this time, the participants were asked to count backwards in threes from a random three-digit number (a distracter task to avoid rehearsal). Findings: After 3 seconds, 80% of the trigrams were recalled, after 6 seconds 50% were recalled, and after 18 seconds fewer than 10% were recalled. Strengths Repeats of the study have found similar findings Limitations artificial stimuli was used- lacking ecological validity and mundane realism participants were given many trials with multiple trigrams and may have become confused

Baddeley (1986) – Working memory Method: got participants to complete two tasks simultaneously: 1. To remember a list of numbers (a so called digit span task) 2. To answer true or false to a number of problems such as BA; A follows B (true or false) Findings: participants were able to correctly answer the second question, although the speed at which they answered slowed and the number of digits increased. Strengths If STM is a unitary (single store) as proposed by the multi-store model, and has a capacity of around 7, then as task 1 reached 7 digits there would be no capacity left to carry out task 2. In fact this was not the case. Both tasks could be performed at the same time.

Loftus and Palmer (1974) – Effects of misleading information Method 1: participants saw a short film of a multiple-car accident. After this, they answered specific questions about the film. Some were asked “how fast were the cars going when they hit each other?” while others were asked the same question but “hit” was replaced with “smashed”, “collided”, “bumped”, or “contacted”. Speed estimates were higher (40.8mph) when “smashed was used as opposed to “collided” (39.3mph), “bumped” (38.1mph) and “hit” (34.0mph) Method 2: participants watched a film of a multiple car accident and either asked “how fast were the cars going when the smashed into each other?” or “hit each other”. One week later they were asked “did you see any glass?” (there was no glass). 32% of those in the “smashed” group claimed that they saw glass but only 14% of those in the “hit” group claimed to see glass. The figure was 12% in controls. Strengths Showed that memory is fragile and easily manipulated Limitations laboratory based and unlikely to engage the witness emotionally artificial stimulus material was used, the eyewitness may not have done their utmost to produce accurate answers (lacks ecological validity) doesn’t show whether the memory itself is altered – information may have just produced response bias.

Dodson and Krueger (2006) – Age and EWT (older) Method: focused on the effect of misleading information for different ages. Younger (college students) and older (60-80) participants were matched in terms of their general memory abilities. Shown a five-minute video clip of a burglary and asked 24 yes/no questions, 4 of which contained misleading information. They were also asked to rate their confidence in the answer. Findings: both had similar rate of suggestibility errors (no difference in the effects of misleading information). Older adults were more likely to believe their answers were accurate, even when wrong. Strengths has important real-world implications: juries tend to be more influenced by an older, confident witness results suggest that this issue of confidence may be an important explanation of wrongful eyewitness convictions matched pairs ensured that differences will not be due to better/worse memories. Limitations laboratory based and unlikely to engage the witness emotionally artificial stimulus material was used, the eyewitness may not have done their utmost to produce accurate answers (lacks ecological validity)

Pozzulo and Lindsay (1998) – Age and EWT (children) Method: meta-analysis of 2000 participants, drawing data from a number of studies which had tested 51 hypotheses. Focused on facial recognition in line-ups. Also compared target-absent and target-present line-ups. Findings: under 5s were less likely to make correct identifications when the target was present did not differ significantly from adults in target-present condition. Children under the age of 13 are more likely to make a choice in the target-absent condition. This is thought to be because they feel compelled to do what they were asked and give an answer. Limitations may lack ecological validity – it may be that young children respond artificially to the controlled conditions of the lab, suggesting that more realistic research needs to be conducted doesn’t explain why children might be more inaccurate – researchers only suggest why young children may be less correct. This is important because sometimes children are the only available source of evidence

Anastasi and Rhodes (2006) – Age and EWT (own age bias) Method: Three age groups of participants recruited: young adults (18-25); middle-aged adults (35-45); and older adults (55-78). Participants were then asked to rate the attractiveness of 24 photographs (Caucasian male and female), drawn from the three age groups. Photos were displayed on PowerPoint at 7-second intervals. There was then a distractor task. They were then shown 48 photographs and asked to indicate, after each one, whether or not they had seen the photo before. Findings: younger and middle aged groups were most accurate. Younger participants recognised younger and middle-aged photos the best, middle-aged participants recognised middle-aged photos the best, and older participants recognised older and middle-aged participants the best. This demonstrates that people recognise people of a similar age the best (own-age bias). Strengths real-world applications to EWT - eyewitnesses will be more reliable is suspect is of a similar age group Limitations may be extraneous variables – Dodson and Krueger research suggests that older participants may be as accurate as other participants but over-identify photographs making them appear less accurate

Johnson and Scott (1976) – Effects of weapon focus on EWT Method: Were asked to sit on their own in a waiting room until it was there turn to be tested. They overheard two people in the next room: (1 high anxiety) two people having a heated argument then one of two people ran through the waiting room holding a letter opener covered in blood. (2 low anxiety) quiet conversation and someone walked through the room holding a pen. The person spoke one line and was in the room for 4 seconds. Participants were asked to identify the person from 50 photographs. Findings: 33% of participants in the high anxiety condition identified the person compared to 49% in the low anxiety condition. Few people noticed the pen whereas most participants noticed the letter opener, suggesting that focus on the weapon may prevent people from noticing important aspects of crime scenes. Limitations the weapon focus effect may be more complex – some studies have shown that it may not effect ability to recognise target person (Loftus et al. 1987) study may test surprise rather than anxiety – Pickrell (1998) conducted an experiment using scissors, handgun, wallet and raw chicken as hand-held items in a hairdressers. Accuracy was much poorer in highly unusual conditions.

Valentine and Mesout (2008) – Effects of anxiety on EWT Method: 56 volunteered were offered reduced ticket price to the London Dungeon if they filled in a questionnaire at the end their visit. During their visit an actor (the scary person/target), dressed in a dark robe, stepped out in front of the participant and blocked their path to prevent them from passing. At the end of the tour they filled in an anxiety questionnaire. Participants were also: asked to recall as many details about the target (free recall); asked specific questions (cued recall); and to identify the target from a line-up of 9. Findings: participants who scored high on state anxiety had less accurate recall than participants who scored low on state anxiety and made fewer correct line-up identifications. There was no effect of anxiety on overall recall (memory). Strengths high ecological validity no demand characteristics because the participants were not aware that their behaviour was going to be assessed important extraneous variables were controlled – although it is a natural experiment some causal assumptions can be made