The American psychologist Marvin Zuckerman defined sensation-seeking as the “need for varied, novel and complex sensations and experiences, and the willingness to take physical and social risks for the sake of such experience.” This should mean that gamblers are higher than non-gamblers on sensation-seeking measures. However, studies in this area have provided contrasting results with some studies supporting the theory, some studies showing no difference between gamblers and non-gamblers, and others showing gamblers to be lower on sensation-seeking than non-gamblers!
In studies on extraversion, the findings have again proved contradictory. Since extraverts are highly sociable, crave excitement, and enjoy noisy and active environments the theory is that gamblers are more likely to be extraverted. Although some studies have indeed found gamblers to be more extraverted than control groups, other studies have found gamblers to have lower extraversion scores or have found no difference.
One personality trait that has received more consistent findings is that of locus of control. This personality trait refers to a person’s perception of how their own efforts effect events. For instance, ‘internal’ individuals attribute their experiences to their own actions whereas ‘external’ individuals attribute their experiences to chance. Research has shown that ‘internal’ individuals gamble more persistently when chasing losses because they believe all that is required is an increase in concentration and an overall improved effort in order to win. However, one of the problems with research into locus of control is that we do not know the direction of causality, that is, whether their particular locus of control preceded the gambling, or whether the gambling preceded their locus of control.
So why are there so few consistent results surrounding personality and gambling? One of the most obvious answers is that gambling is multi-faceted and not a unitary phenomenon. Treating all forms of gambling as equivalent in terms of underlying psychology, personality or motivation may cloud the issue rather than clarify it. For instance, can we really say that a regular lottery player has similar underlying psychology to a regular slot machine player? Is an online poker player similar to a roulette gambler? Of course not. And that is one of the main reasons for inconsistent findings. Psychologists have tended to clump gamblers together as if they were a unified and homogenous group of people.
It would appear from the research carried out to date that the usefulness and the value of psychometric-based personality studies remain doubtful. The notion that gamblers possess a unique set of variables or traits is a naive over-simplification and appears to be a fruitless direction for research. Gambling is complex and multidimensional, and personality factors are too 'global' to serve as the single cause. Research into gambling is still at a relatively early stage, and it is clear that a person’s gambling behaviour results from an interaction between many different variables including environmental, social, psychological and biological.