Memory pt3

• Retrieval failure


  Forgetting in long-term memory occurs because of insufficient cues to trigger a memory
• Encoding specificity principle


  A cue that is going to be helpful has to be (1) present at encoding (when we learn the material) and (2) present at retrieval when we are recalling it
• Types of retrieval failure due to absence of cues


  • Context-dependent forgetting
  • State-dependent forgetting
• Context-dependent forgetting


  Recall depends on external cue (e.g. weather or place)
• State-dependent forgetting


  Recall depends on internal cue (e.g. feeling upset, being drunk)
• Research on context-dependent forgetting: Godden and Baddeley (1975)


  • Divers learned words either underwater or on land, then recalled them either underwater or on land
  • Accurate recall was 40% lower when learning and recall contexts did not match
• Research on state-dependent forgetting: Carter and Cassaday (1998)


  • Participants learned words and prose while on antihistamine drugs, then recalled them either on or off the drugs
  • Performance was significantly worse when internal state at learning and recall mismatched
• Eyewitness testimony (EWT)


  The ability of people to remember details of events, such as accidents and crimes, which they have observed
• Misleading information


  When the wording of a question leads or misleads a witness to give a certain answer
• Research on leading questions: Loftus and Palmer (1974)

  1. Participants watched film clips of car accidents, then were asked questions using different verbs (e.g. smashed, hit) to describe the speed

  2. The leading question biased the eyewitnesses' recall of the event
• Response-bias explanation


  The wording of the question has no real effect on the participants' memories, but just influences how they decide to answer
• Substitution explanation


  The wording of a leading question changes the participants' memory of the film clip
• Research on post-event discussion: Gabbert et al. (2003)


  1. Participants watched a video of a crime from different viewpoints, then discussed what they saw before recalling it

  2. 71% of participants mistakenly recalled aspects they did not see, due to memory conformity or contamination
• The consequences of inaccurate eyewitness testimony (EWT) can be very serious
• Loftus (1975) believes that leading questions can have such a distorting effect on memory that police officers need to be very careful about how they phrase their questions when interviewing eyewitnesses
• Psychologists are sometimes asked to act as expert witnesses in court trials and explain the limits of EWT to juries
• Psychologists can help to improve the way the legal system works, especially by protecting innocent people from faulty convictions based on unreliable EWT
• Sutherland et al (2001) found that when participants were shown a video clip and then later asked misleading questions, their recall was more accurate for central details of the event than for peripheral ones
• The original memories for central details survived and were not distorted, an outcome that is not predicted by the substitution explanation
• Anxiety has strong emotional and physical effects, but it is not clear whether these effects make eyewitness recall better or worse
• Anxiety creates physiological arousal in the body which prevents people from paying attention to important details, leading to worse recall
• The weapon focus effect is where a witness focuses their attention on the weapon being used in a crime, leading to difficulties in recalling other details accurately
• Johnson and Scott (1976) study


  1. Participants exposed to 'no-weapon' (low anxiety) condition or 'weapon' (high anxiety) condition

  2. Participants later picked out the target from a set of photos

  3. Participants who saw the weapon were more likely to identify the target
• Participants who were exposed to the knife had higher levels of anxiety and were more likely to focus their attention on the weapon and not the face of the target, a phenomenon known as the weapon focus effect
• Witnessing a stressful event creates anxiety through physiological arousal within the body, which may improve memory for the event as we become more aware of cues in the situation
• Yuille and Cutshall (1986) study


  1. Interviewed 13 witnesses of a real-life shooting 4-5 months after the incident

  2. Compared accuracy of recall to original police interviews

  3. Witnesses who reported higher levels of stress were more accurate in their accounts
• Yerkes-Dodson law


  The relationship between emotional arousal and performance looks like an inverted U - performance increases with stress up to an optimal level, then decreases
• Deffenbacher (1983) reviewed studies on the effects of anxiety on EWT and used the Yerkes-Dodson law to explain the contradictory findings
• Valentine et al found that anxiety (measured by heart rate) clearly disrupted participants' ability to recall details about an actor in the London Dungeon's Labyrinth