International Journal of Mental Health and Addiction

, Volume 9, Issue 1, pp 60-71

First online:

What Does a Random Line Look Like: An Experimental Study

  • Nigel E. TurnerAffiliated withCentre for Addiction and Mental HealthDepartment of Public Health Sciences, University of Toronto Email author 
  • , Eleanor LiuAffiliated withCentre for Addiction and Mental Health
  • , Tony ToneattoAffiliated withCentre for Addiction and Mental HealthPublic Health Sciences and Psychiatry, University of Toronto

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The study examined the perception of random lines by people with gambling problems compared to people without gambling problems. The sample consisted of 67 probable pathological gamblers and 46 people without gambling problems. Participants completed a number of questionnaires about their gambling and were then presented with a series of random and non-random lines. The participants rated lines as random if the pattern stayed near zero (the middle of the screen) and did not form anything that resembled waves. The probable pathological gamblers rated 2 of the patterns (jumps, and multi-wave) as significantly less random than non-problem gamblers. They also rated random lines significantly less random than the non-problem gamblers. That is, they seem to be able to find patterns both when they are really there and when they only appear to be there as in the case of random drift.


Problem gambling Random chance Erroneous beliefs