Subliminal priming of winning images prompts increased betting in slot machine play

Abstract In2experiments( n = 327),participantsplayedacomputerizedslotmachinegame.Someparticipantshadthejackpotsymbolsrepeatedlyﬂashedfor30msduringpre-liminaryplay.Exposuretothesubliminaljackpotprimeledtomorebettingandcon-ﬁdence on a ﬁnal spin. In Experiment 2, this effect only occurred for those whoplaced their bets immediately following exposure to the primes.Betting and conﬁ-dence returned to baseline levels if participants were forced to wait for 5 minutesbefore betting.This ﬁnding supports a category priming explanation rather than agoal activation explanation for the effect. Results are discussed in the context ofresearch on subliminal priming,and as an example of an application of subliminalprimingeffectstoconsumerpsychology.Ontario’s provincial gambling operator has pulled 87video slot machines out of service or physicallyremoved them from its casinos after a CBC investiga-tion found what appear to be subliminal messagesﬂashing at players (Canadian Broadcasting Corpora-tion,2007).Gamblingisbigbusinessanditgarnersasigniﬁcantportionofconsumers’entertainmentdollars.RecentdatareportthatthegrossrevenueforthegamingindustryintheUnitedStatesin2006 (including casinos, lotteries, legal bookmaking, horseracing, and bingo) was over $90 billion (American GamingAssociation,2008).Notincludedinthisestimateareavarietyof illegal forms of gambling and small stake bets placedbetween individuals. Clearly, many people are interested ingambling,andwillgambledespitethenegativeexpectedvalueofmostofthebetsofferedbycasinosandlotteries.Avarietyofpsychologicalmechanismshavebeenexploredinanattempttounderstandpeople’swillingnesstobet.Somehavefocusedonindividualdifferencesinpropensitytogamble(CoventryB Gibson & Sanbonmatsu, 2004; Hong & Chiu,1988)whileothershavefocusedoncognitivemechanismsthatcould increase the appeal of certain bets (Gibson, Sanbon-matsu,PGilovich,1983;GilovichD Langer, 1975; Windschitl & Chambers, 2004). Inthe current research, we address the possibility thatpriming players with subliminal winning images couldalteragambler’sevaluationof agivenbet,therebyincreasingthelikelihoodthatalargerbetisplaced.Could casinos potentially manipulate betting throughpresentation of subliminal winning images? Certainly, themundane, supraliminal cues in a casino environment aremanipulated in a variety of ways to prompt and maintainbetting from casino patrons (Kranes, 1995). For example,casinos attempt to encourage longer periods of betting, andhence more losses, by limiting cues to the passage of time.Thus,windows and clocks are scarce within the casino envi-ronment. Similarly, casinos make wins noticeable by havingbellsringorsirensplaywhenajackpotishit,orbyannounc-ing big winners over a public address system. These supra-liminalremindersof winningmayservetomakeconceptsofwinning more accessible in the minds of casino patrons,potentiallyalteringplayers’evaluationsof theirownchancesof winning. We propose that similar processes may beengaged by the presentation of subliminal winning images.Patrons who played the slot machines in the Ontario casinothought so. Although the slot machine’s manufacturerclaimed that the ﬂashed images were an unintentional glitchinthemachines,someplayersreportedthattheseimagesledthem to bet more (CBC News, 2007). Although we wouldquestiongamblers’abilitytointrospectabouttherootcausesof their gambling choices, let alone how unnoticed imagesaffected their bets, the possibility that subliminal imagescouldincreasebettingshouldnotbedismissedoutof hand.