Cognitive Psychology

Short Term Memory :                                                                                                                   

Capacity : 7+/- 2 Jacobs                                                                                                                  Participants string of unrelated letters/digits increase each time by one letter. Capacity measured at point could no longer recall correctly.

Duration : 18-30 seconds Peterson and Peterson                                                                               Participnats shown a trigram then had to count down in threes from a given number. Stopped in intervals and asked to recall the trigram.

Encoding : Acoustic Baddeley                                                                                                          Participants looked at numbers and asked to recall, then read out numbers and asked to recall. Best results when the numbers were read out.

Long Term Memory :

Capacity : Potentially unlimited Wagenaar                                                                                                Created a diary of events, then tested himself and recalled a large amount

Duration : Up to a life time Bahrick et al                                                                                                     High school graduates would had graduated between 1-50 years past. They were shown a number of pictures and asked to recoginse class mates faces or the name of the person

Encoding : Semantic Baddeley                                                                                                                   Four lists of words, similar sounds, similar meaning, different sounsds and different meanings

Strengths

•  Case studies support, poor LTM but functioning STM
•  Lab experiment, contorl of extraneous variables
•  Influencial model, helped increase understanding over last 40 years

Limitations

•  Over simplistic, no explanation for flashbulb memories
•  Over use of Lab methods can reduce ecological validty
•  knowledge based on bias so is unrepresentative, reduces population validity

Memory model looking further in the STM

Baddeley and hitch (1974)

Dual tasks (speech, hearing, seeing). STM has different elements and phonologcal loop and the visuo spacial sketchpad can under go tasks simultaneously.

Baddeley et al (1973)

Dual tasks, if within the same slave system task will be hard to do

Strengths  

• Case studies such as KF better explained through the model
• PET scans show different parts of the brain used for different tasks
• helped with understanding dyslexia, real world application

Weaknesses

• Most eveidnece from damaged patients, cannot compare with un damaged and reduces population valaidity
• Overuse o the Lab method reduces ecological validity
• Information vague no indepth info about capacity, duration, encoding

Loftus and Palmer (1974) (a)

Shown video of the car crashed and put into 5 grups and asked the speed of the car using 5 different verbs Smashed, collided, bumped, hit, contacted

Smashed group : 40.8 mph

Contacted group : 31.8 mph

Misleading information can readuces accuracy of eye witness testimony

Loftus and Palmer (1975) (b)

Shown the same video as from the first experiment then asked either

Did you see a broken headlight? (7% yes)

Did you see the broken headlight? (17% yes)

IMPROVES (Christianson and Hubinette (1993)

110 people surveyed who had witnessed 22 different bank robberys

HIgher anxiety levels where seen in participants who were direct victims who gave more detailed and more accurate reall

WORSENS (Loftus (1979)

Listened to a normal converstation and saw a man walk out with grease on his hands and holding a pen

Listened to a heated converstaioin and saw a man who walked out with a knife covered in blood

asked to identify the man from 50 photos; group who saw the more violent scene wereless accurate (33%) those with lower anxiety were better (49%)

Yarmey (1993)

Found no significant differences between ages in ability of recall, younger participants where just more confident about their accuracy.

Yarmey (1984)

when asked questions about an staged event 80% of the elderly participants could not recall the weapon compared to the 20% of younger participants

1. Context reinstatement think about the weather and the feelings they encounted that day
2. Report Everything reporting even things with seem completeley irrelevant
3. Recall from a Changed Perspective recall from different points of view
4. Recall in Reverse Order recalling in different orders strengthen neuro pathways