The Near-Miss in Slot Machines: Over Half a Century Later Jeffrey M

The near-miss in slot machines: Over half a century later Jeffrey M. Pisklak1*¶, Joshua J.H. Yong1¶, Marcia L. Spetch1 1 Department of Psychology, University of Alberta, Edmonton, Alberta, Canada * Corresponding author E-mail: [email protected] (JMP) ¶These authors contributed equally to this work. Abstract In games of chance, a near miss is said to occur when feedback for what is otherwise a loss approximates a win. For instance, obtaining “cherry-cherry-lemon” on a slot machine could be considered a near miss. Sixty-six years after B. F. Skinner first proposed the idea that near- miss events might reinforce continued play in slot machines, belief in this ‘near-miss effect’ has remained strong despite some inconsistencies in the experimental literature. The present study reviewed and experimentally assessed the near-miss effect as it pertains to the frequency of the gambling response. Experiment 1 used a tightly controlled resistance-to-extinction procedure in pigeons to evaluate the putative reinforcing effect of near misses relative to a control “far-miss” reel pattern. Experiment 2 extended Experiment 1’s procedure to human participants. The results of both experiments failed to support the near-miss effect hypothesis. Experiment 3 used a further simplified procedure to assess the validity of the resistance-to-extinction paradigm when a probable conditional reinforcer was present on the reel stimuli. Although a clear discriminative function was obtained from the reel, subsequent testing in extinction revealed no reinforcing function of this stimulus. Introduction Near misses, also called near-hits or near wins, can generally be said to occur when the elements of a game or task “suggest” to a player that they have almost achieved a favourable result. A good example is provided by Witts, Ghezzi, and Manson [1]: Consider a novice player making repeated free throws in basketball. With each successive throw, variations in the throwing technique that get the ball closer towards the net and eventually into the hoop tend to 2 increase in probability (i.e., are selected for). This is an instance where the “near miss” can be said to have a clear reinforcing function on the player’s free-throw behaviour. Near misses are not exclusive to games of skill – they also occur in games of chance. However, the crucial difference is that in a game of chance, the outcome is practically a random event. On a standard slot machine, if a win can be signalled by “cherry, cherry, cherry” then a combination of “cherry, cherry, lemon” would be considered a near miss. Modern slot machines contain a pseudo-random number generator (RNG) that cycles through about 4.3 billion distinct values continuously at approximately one thousand values per second. When a player places a bet, the machine selects the cycle’s current position and correlated reel positions are subsequently output onto the display [2]. Unlike the basketball player practicing his free throw however, no amount of practice will ever produce the type of superhuman reflexes and discriminative capacity that a gambler would need to improve at slot machine playing. Moreover, even if one possessed such powers, the random number generation employed by the machine means that receiving a near miss is no more informative to understanding the RNG cycle than any other type of miss (e.g. cherry, bell, lemon). In other words, the “cherry, cherry, lemon” combination is no “nearer” to a win than any other possible combination. This raises an important question: if the near miss inside a game of chance is independent of a win (i.e., cannot be used to help to determine the occurrence of a win) then why is it considered a “near” miss? The obvious answer seems to be that the near miss is visually “nearly” a win. For example, if three cherries constitute a win, then receiving two cherries and a lemon necessarily looks more similar to that win than receiving a single cherry and two lemons. In the case of the basketball free throw, the visual aspects of the situation provide helpful feedback to the player. Near-miss feedback on slot machines, however, offers no practical use for improving 3 performance. One possibility is that the visual aspect of the near miss is exploiting learning processes evolved to detect contingent (i.e., non-random) outcomes inside the environment. Conditional reinforcement is one such learning process that has been hypothesized to fall victim to this exploitation. Conditional Reinforcement Conditional reinforcement has long been assumed to play a significant role in various instances of gambling behaviour. As early as 1953, B.F. Skinner utilized conditional reinforcement in what is likely the first scientific account of near misses [3]. Skinner’s account drew upon conditional reinforcement as one of a set of plausible methods casinos were using to exploit their patrons and it is still cited as an explanation of the near-miss effect – the idea that near-miss events contribute to an increased frequency of gambling by the player – a widely held belief among many gambling researchers. More formally, in this paper we define the near-miss effect as the hypothesis that near-miss events in a game of chance have a reinforcing function on the player’s total frequency of play. Skinner’s original hypothesis rested on two critical factors: 1) that the pairing (i.e., contiguity) hypothesis of conditional reinforcement is correct, and 2) that near misses do in fact cause an increase in the frequency of betting responses. At the time Skinner proposed this, the available lines of evidence had been largely supportive of a basic pairing account of conditional reinforcement, and the reinforcing effect of near misses would have been a sensible a priori prediction. Since that time, however, research has shown that the basic pairing account is inaccurate and predicating near-miss effects based on this is questionable. Early theorizing conceptualized conditional reinforcement effects as a product of respondent (i.e., Pavlovian) conditioning, which was heavily dominated by accounts of temporal contiguity (i.e., pairing). Although it is parsimonious, referring to “pairing” as the circumstance 4 under which respondent conditioning will occur is now widely acknowledged as overly simplistic since it ignores the many nuances that influence and characterize this type of learning [4-5]. Additionally – and irrespective of contemporary discussions of respondent conditioning – evidence suggests that pairing is not sufficient to produce a conditionally reinforcing effect [6-7]. Contemporary accounts of conditional reinforcement now place a stronger emphasis on the role of contingency, as opposed to strict pairing, and are usually framed in terms of two prominent mathematical models: delay reduction theory and the hyperbolic decay model [8]. Despite wide acceptance of the delay reduction theory and the hyperbolic decay model in behaviour analysis, contemporary near-miss studies still conceptualize the near-miss effect through the pairing formulation [9]. Also, although there is considerable evidence that near miss events can affect subjective measures (e.g. self reports) and physiological responses (e.g. skin conductance, heart rate or brain activity), and some studies have shown effects on betting size, there have been surprisingly few direct experimental tests of the presumed reinforcing function of near misses on gambling persistence. Effects on subjective motivation or physiological responses are consistent with a reinforcing effect on gambling frequency, but without a direct behavioral measure of persistence, they do not actually demonstrate such an effect [10-14]. Moreover, attempts at assessing near-miss effects in terms of delay reduction theory or the hyperbolic decay model are essentially nonexistent. This may be due to the manner in which conditional reinforcement studies are often conducted. Most experimental paradigms testing conditional reinforcement employ some type of chained schedule of reinforcement. Two or more schedules of reinforcement are presented one after the other and are signalled by unique exteroceptive stimuli. Even complex paradigms such as observing response procedures and token economies are considered as such. One means of 5 assessing the conditionally reinforcing effect of a stimulus within the chain is to institute an extinction contingency and then compare the responding in the presence and the absence of the putative conditional reinforcer. This procedure is known as the established response technique and, as noted by Kelleher and Gollub in their exhaustive review of early conditional reinforcement literature [15], has the benefit of excluding the confounding effects of known reinforcers from testing, but the procedure may inadvertently introduce other problems. For example, extinction may alter the context such that the stimuli no longer function in the same way that they did during training (i.e., the stimuli may be “viewed” differently by the organism). An additional problem noted by Kelleher and Gollub is that breaking the chain via extinction in the established response technique tends to produce only small effect sizes – presumably because the conditional reinforcer is being simultaneously tested and extinguished. This creates a difficulty for investigating the near-miss effect because even if near misses have a reinforcing effect, the observed effect may be small. Conventional chained procedures that successfully produce conditional reinforcement in laboratories have a logical predictability (i.e., contingency); the same cannot necessarily be said of the classic slot-machine scenario where randomness interrupts any logical predictability. This could diminish or even remove any conditionally reinforcing effect. Near Misses as Global and Local Events An overlooked point in near-miss articles is that near misses can be conceptualized globally or locally. For instance, the elements that occur on a basic three-reel slot machine (e.g., cherry, cherry, lemon) could be viewed globally, as a single stimulus, or they could be viewed locally, as three separate stimuli. This distinction matters according to conditional reinforcement.

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