Griffiths core study

  • Created by: Koala
  • Created on: 16-05-15 18:38

Aim & Hypotheses

  • compare the behaviour and cognitions of regular and non-regular gamblers to see if there were differences

1. No difference between RGs and NRGs on objective measures of skill in gambling

2. RGs more irrational verbalisations than NRGs (thinking aloud method)

3. RGs will report themselves to be more skill-oriented than NRGs on subjective measures of skill

4. Participants in the thinking aloud condition will take longer to do the task compared to those not in the conidition

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  • 60 participants, mean age 23.4 years
  • 30 RGs (29M, 1F- gender imbalance due to fruit machine gamblers being mainly male in the UK)-gambled at least once a week
  • (control group) 30 NRGs (15M, 15F)-gambled once a month or less, but had used the fruit machines at least once before the study
  • Self selected volunteers- posters around local college campuses
  • Snowball sampling from a known RG to Griffiths
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  • £3 to gamble on a fruit machine in a local arcade
  • Game selected was FRUITSKILL
  • Players had to stay on their machine for at least 60 gambles
  • At that point, they could keep their £3 or carry on gambling
  • Half the participants of each group were randomly assigned the thinking aloud condition

Thinking aloud method

  • say everything and do not censor your thoughts
  • talk continuously in full sentences
  • do not try to justify your thoughts
  • verbalisations later transcribed by two raters- one knew little about fruit machine gambling and the other had no context of the study

Self report-post experimental semi structure interviews

  • three questions asked to measure perceptions of skill
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Hypothesis 1 supported: generally no significant differences, however

  • RGs had a higher playing rate- 8 per min
  • RGs who thought aloud had a lower win rate

Hypothesis 2 supported: RGs used a variety of heuristics, showing cognitive bias (verbalisations analysed using content analysis)

  • NRGS- verbalising confusion 4.81, higher than RGs e.g. 'I don't understand this'
  • RGs- machine personification 7.54, higher than NRGs
  • RGs more irrational verbalisations (14% compared to 2.5% in NRGs) e.g 'The machine likes me', 'This machine... hates me', 'It wants its money back'
  • RGs more rational verbalisations with reference to the number system

Hypothesis 3 supported: RGs/NRGs- equal chance and skill/mostly chance, above average/below average, feature skills and knowing when the machine will pay out/ no skill

Hypothesis 4 supported: RGs who thought aloud had a lower win rate in plays and therefore made fewer gambles between wins than the other groups

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  • P: RGs have different cognitive processes than NRGs
  • E: RGs think that more skills are involved, make more irrational verbalisations
  • E: However, only fruit machine gambling studied and not other forms
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Change 1


use a self report questionnaire and ask the participants what they were thinking while they were playing on the fruit machines. use all open questions, instead of the thinking aloud condition. fill out the questionnaire at the end of the 60 plays


participants could play normally without being disturbed by the thinking aloud condition, higher validity. they could explain their thoughts in phrases that the NRGs would understand- higher inter rater reliability


would allow participants to censor their thoughts- social desirability, would rely on memory- likely to be inaccurate, reduce validity


increased validity of the results- more generalizable

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Change 2


investigate different forms of gambling- e.g poker. repeat the same experiment but get participants to play poker in lab conditions. 60 participants collected using self selected/snowball sampling- 30 NRGs and 30 RGs. 15 RGs and 15 NRGs randomly assigned thinking aloud condition. each player given £5 at the beginning to play one game against a confederate of Griffiths who is a gambler- unknown to participants.


increase validity- more information about the way gamblers think, make comparisons between this repeat and the experiment with fruit machines


time consuming, thinking aloud condition may be difficult if noisier, more difficult to standardise

Implications gamblers use similar cognitive processes across different types of gambling or might find that some genuinely require more skill- use different heuristics. likely to find that RGs make more irrational verbalisations still

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