Slot machine games, as found on the fixed odds betting terminals of many high street betting shops, have subtle ways of telling players not just whether they have won or lost, but also whether they “almost won”.
One of the best-understood ways is called the near-miss effect: that is, when the display on a losing slot machine physically resembles an actual win display (such as two out of three matching symbols on the pay-line). Near-misses are actually losses, but previous research shows they may promote continued gambling because the brain interprets them as being similar to wins.
New research shows that near-misses are underpinned by changes in the brain’s electrical activity, particularly in the theta (4-7 Hz) frequency range, a frequency known to be involved in processing win and loss outcomes. These changes occur in similar brain regions to actual wins and are linked to both how severe someone’s gambling history might be and how susceptible they are to developing a future gambling problem.
“Problem gambling is a growing social concern, and the brain and behavioural effects of ‘almost winning’ are now well documented. Advances in brain imaging techniques mean we are now able to pinpoint the precise brain regions involved in the near-miss effect and identify how they interact with people’s vulnerability to problem gambling”, explained Dr. Simon Dymond, Reader in Psychology at Swansea University who led the research, which was published in NeuroImage*.
The researchers studied male gamblers and non-gamblers and exposed them to simulated slot machines presenting win, loss and near-miss outcomes. They underwent a brain scan using a technique called magnetoencephalography (MEG), which measures both the timing and location of brain responses to different gambling outcomes. The team found that theta activity increased in response to near-misses relative to other losses in brain regions such as insula and orbitofrontal cortex (OFC), which was linked to gambling severity.
These findings show, for the first time, that “gamblers have an exaggerated theta response to almost winning in brain regions related to reward processing, which could contribute to them continuing to gamble despite their losses”, commented Dr. Natalia Lawrence, Senior Lecturer at Exeter University, and joint first author on the study. “If replicated, these brain activity changes could help us identify those vulnerable to gambling addiction and might be a useful measure of the effectiveness of therapy for gambling related problems”, said Dr. Lawrence.
What this study does show:
- Brain responses to near-misses resemble those to actual wins.
- Brain responses to near-misses are associated with increased theta activity in gamblers.
- Gamblers’ level of reported gambling severity and susceptibility to thoughts about gambling predicted activity in brain regions responsible for the near-miss effect.
What this study does not show:
- That brain responses to near-misses cause gambling problems.
- That the present findings apply to everyone – here, only males with some gambling experience were included.
- That vulnerability to gambling problems can be predicted by theta changes.
Dymond, S., Lawrence, N.S., Dunkley, B., Yuen, S.L.K., Hinton, E.C., Dixon, M.R., Hoon, A.E., Munnelly, A., Muthukumaraswamy, S.D., & Singh, K.S. (in press). Almost winning: Induced MEG theta power in insula and orbitofrontal cortex increases during gambling near-misses and is associated with BOLD signal and gambling severity. NeuroImage. doi: 10.1016/j.neuroimage.2014.01.019
- Friday 3 January 2014 10.07 GMT
- Tuesday 25 February 2014 21.15 GMT
- Ian Russell