KF case study (Shallice and Warrington)

case

case

KF suffered from brain damage due to a motorcycle accident

issue

what they realised was that the digit span of KF was only 2 digits (normal people on average can remember 7). Shallice and Warrington also realised that KF's short term forgetting of auditory letters and digits was much greater than his forgetting of visual stimuli. They also learned that KF's short term memory deficit was limited to verbal materials (letters and words) and not not to meaningful sounds (cats mewing).

methods

They used triangulation techniques to find these defects

They conducted 5 different experiments, the 1st one:

1. Free recall: 10 high frequency words each of 4-5 letters were read to KF at a rate of 1 word per 2 seconds. Kf was then given 1 minute for the recall. 30 words were presented over 3 testing sessions

Second experiment

2. Modified Peterson Procedure three three letter words were voiced to him at a rate of 1 word/second. And then he was asked to count in ones from 1 as fast as e could. The end of each counting interval was signalled by the instructor saying "now". A new trial was begun when it KF could have recalled no more. There were 5 initial trials followed by 16 trials.

Third experiment

3. Proactive Interference test: Ten series each containing 10 pairs of letters were spoken to K.F. The two letters of a pair were separated by 1 second. and there was 5 seconds to recall the 2 letters before the next pair was presented. there was a minute gap between each series.

4. Recognition using a Probe Technique : The experimenter spoke a string of 5 letters to K.F. at a one per second rate, a tap marking the end of the series. Three retrieval conditions were used.

A, the experimenter presented a probe letter to K.F., who had to say whether or not it had appeared in the string.

B, K.F. had to repeat the last letter of the string before being presented

C there was a 20-sec. interval between the end of the string and the presentation of the probe letter. Sets of 8 strings were used, 4 in which the
probe letter had not occurred and 4 in which each of the first 4 serial positions were probed.
Before each set K.F. was told which retrieval condition was to be tested. Twenty-seven sets
of each of the three conditions were presented to K.F. in a randomised design.

K.F.'s missing scan was tested for digit sets of size 3,4

strengths

Triangulation because Shall-ice and Warrington analysed this case study through various different experimental techniques.

Provides information from unreachable situation AKA KF.

This provides stimulating new research on aspects of cognitive psychology that was not considered before.

limitations

It is only one source do there is limited generalisability

These studies were mainly in a lab environment so there is low ecological validity

These studies also lacked mundane realism

Low levels of replicability because this data is only specific to KF