Evaluation: Strengths: A major strength of this study was the amount and type of data collected. The behavioural data such as fruit machine gambling was quantitative and this allows for comparisons and statistical analysis to be made. Furthermore the qualitative data collected from the verbalisations were quantified using content analysis again allowing statistical comparisons to be made. The transcripts and the post experimental semi-structured interview also provided qualitative data allowing the research greater insights into the heuristics used by the participants.The thinking aloud method can be seen as a very useful way of assessing private thought processes as it allows the research to capture some of the thoughts of the participants as they actually gambled. Weaknesses: It is doubtful whether this technique did capture all of the thoughts of the participants for example some participants may have censured their thoughts, would not be able to put into words their thoughts and of course their were periods of time (up to 30 seconds) when the participants were silent. Griffiths did recognise that there was a problem with the inter-rater reliability of the coding system. Griffiths completed the coding of the verbalisations himself and had a second researcher code the same results but the inter-rater reliability was low. There could be issues with demand characteristics in the study. The participants were aware they were being studied and may have responded when verbalising their thoughts, playing the fruit machine or responding to the interview in ways they thought the experimenter wanted them to behave.There could also be issues with social desirability particularly with the regular gamblers. There was a problem in the study in that some of the regular gamblers did not want to play on the chosen fruit machine and instead chose to play on their favourite one. Therefore some of the differences between regular and non-regular gamblers could have been caused by the different machine.