Since the emergence of multimedia cellular phones in the mid-1990s, mobile phone gaming has claimed some degree of presence in our continuous, ‘on-the-go’ lifestyle. From the initial craze surrounding the game “Snake” on early Nokia devices, our mobile gaming habits have been transformed by the ever-expanding quality, sophistication and overall usage of smartphone technology. Of particular interest is the surging popularity of Candy Crush Saga—a free-to-play, candy themed puzzle game that has captivated at least 93 million daily active users in 2014, and generated $2.2 billion in profits (mostly from in-app purchases) in that same year (King Ltd 2015).
To play Candy Crush, players are allotted a fixed number of moves in which they can swap symbol positions with the goal of horizontally or vertically aligning three (or more) matching symbols. When matched symbols are aligned, points are awarded and the ‘captured’ matching symbols are removed from the game matrix (and replaced by other symbols). A single match constitutes one move. In each level of the game, the player must achieve a specific objective within a limited number of moves before the player can unlock the next level. The objectives can include bringing a certain number of ‘ingredient’ symbols to the bottom of the game matrix (in game play players are instructed to “Collect all 6 ingredients!”), or ‘freeing’ candy symbols encased in ‘gelatine’ or ‘jelly’ tiles (e.g. “Clear all the jellies!”). If the player meets the objective within the allotted number of moves they win, and move on to play the next level (colloquially known as “levelling up”). If they fail to meet the objective in the allotted number of moves they lose, and remain at the current level, which they must repeat if they wish to move on in the game.
Since games like Candy Crush are typically played on smartphones, they encompass a unique set of traits that distinguish them from console-type video games but intriguingly, bring them closer to the conceptual realm of slot machines. For example, like slot machines, smartphone games are easy to learn, and players are frequently reinforced as each successful move is accompanied by eye-catching animations of points being accrued as the aligned symbols are captured. Perhaps most importantly, play is continuous- there is always a next level to play (The Economist 2013). Although Candy Crush (like most phone games) lacks a direct gambling element in that no money is wagered on outcomes, money nevertheless can change hands. Players can, if they wish, purchase game currency that can be used to gain extra lives, extra moves or bonus accessories as a way to maximize their likelihood of winning and advancing in the game. Although less than 3 % of players end up making such transactions (Grubb 2014), the players who do, spend on average $23.42 per month on these micro-transactions (Grubb 2014).
The monetization of gaming through these micro-transactions blurs the dividing line separating regular video-gaming and gambling for money. In addition to the negative impact of excessive video-game play on overall social, physical and psychological well-being (Ferguson et al. 2011), some players can, and do spend more than they can afford on these games (Lloyd 2016).
Structural Similarities Between Casual Games and Gambling Games
Several speculations comparing the structural similarities of Candy Crush and slot machines have been made in attempt to explain why Candy Crush has such an ‘addictive’ quality (see Smith 2014; Gardner 2014). Tellingly, Candy Crush players often specifically liken Candy Crush to slot machine play to convey its appeal. They highlight the enticing animations that accompany successful moves, and levelling up (Smith 2014). Moreover, the fact that a correct move is characterized by the alignment of matching candies parallels the alignment of matching symbols on the pay-line in slot machines. Furthermore, players attempting to gather (or capture) candies may allude to the indirect consumption of these forms of foods—a pleasurable experience which many of us are motivated to repeat (Lowe and Butryn 2007; Gardner 2014). Such game themes where food symbols are paired with reward are evident in many slot machines. In fact, in the United Kingdome, slot machines are colloquially referred to as ‘fruit’ machines (Griffiths 1993).
The parallels between slot machine play and Candy Crush involve not only rewarding events (winning spins, levelling up), but also frustrating events. Near-misses are outcomes that come close to, but fall just short of a win (Reid 1986). In traditional 3-reel slot machine games, a classic near-miss is represented by two high paying symbols matching up on the first two reels, and a 3rd matching symbol stopping right before or just after the pay-line (“7-7-X”). Thus, the player falls just short of the big win. In Candy Crush, the program specifically highlights attempts that fall just short of the goal of levelling up. For example, if the player needed only 2 moves to level up, but ran out of the allotted number of moves they would see the move counter drop to zero, followed by a message claiming “Out of moves! You only needed 2 more jellies”. In contrast, if the player was not close to levelling up, the move counter would simply drop to zero and the message would simply state “out of moves”. As such there is a clear attempt to highlight to the player those instances where players came close to, but fell just short of the goal of the game. We refer to these outcomes as Candy Crush near-misses.
Although no studies have investigated the ramifications of Candy Crush near-misses, one can make reasonable inferences based on near-misses in other scenarios. In slot machine games, near-miss outcomes encourage the urge to continue play despite the absence of reward (Côté et al. 2003; Kassinove and Schare 2001; Clark et al. 2009; Billieux et al. 2012). In general, the idea of falling just short of a big win appears to facilitate players wanting to continue with the game in the belief that practice makes better, or more spins will eventually lead to success (Kassinove and Schare 2001).
Because a near-miss reflects a thwarted goal, it tends to provoke a negative emotional experience. While players rate slot machine wins as being pleasant, they rate near-misses as being unpleasant and more aversive than regular losses (Clark et al. 2009; Chase and Clark 2010). One means of capturing the rewarding property of wins and the aversive property of near-misses during actual play is by measuring a combination of Post-reinforcement Pauses (PRPs) and Skin Conductance Responses (SCRs). Post-reinforcement pauses are typically defined as the time it takes to initiate a new response after a specified reinforcement (Felton and Lyon 1966). In slot machine play, PRPs are operationalized as the time interval between the delivery of an outcome (e.g. win, loss, or near-miss) and the initiation of the next spin (Dixon et al. 2013; Dixon and Schreiber 2004; Delfabbro and Winefield 1999). After having participants play a slot machine, Dixon et al. (2013) found relatively long PRPs for winning outcomes compared to near-misses (and other standard losses). Players’ faster initiation of the next spin following a near-miss outcome was seen as an attempt to escape the unpleasantness of just missing the win (Dixon et al. 2013). Research measuring arousal (quantified by SCRs) complement this interpretation (Lobbestael et al. 2008; Civai et al. 2010). During slot machine play, wins trigger significantly larger arousal responses than losses, presumably due to their exciting properties. Near-misses, however also trigger large skin conductance responses than regular losses—a finding Dixon et al. (2011, 2013, 2015) attributed to their frustrating properties. In sum the combination of long PRPs and large SCRs was viewed as a signature of reward-induced arousal, whereas the combination of large SCRs but small PRPs was seen as a hallmark of frustration. Based on the slot machine literature, it is reasonable to surmise that near-misses in Candy Crush (just failing to level up by one, two or three moves) might induce similar frustration that could be operationalized by the combination of large elevations in skin conductance and short PRPs.
Near-misses influence players in different forms of gambling. For example, a recent study by Stange et al. (in press) investigated near-misses in scratch card play. Players uncovered a series of symbols hoping to find three matching symbols within a 3 × 2 symbol matrix. They compared losing outcomes (no matching symbols), winning outcomes (three $5 symbols leading to a small win) and near-miss outcomes (where only two of three “jackpot” symbols were uncovered and players “just missed” winning a large prize). In such a game, the outcomes are only known once the last symbol in a matrix is revealed. Stange et al. (in press) showed that during near-misses (compared to regular losses), as players successively revealed a first, then a second jackpot symbol their skin conductance levels (SCLs) increased presumably due to increases in arousal in anticipation of the big win. Elevations in Heart Rate (HR) also took place during near-misses as the first and second symbol were uncovered. They also found that subjective frustration ensued when players uncovered the last symbol and their hopes were dashed. We surmise that this anticipatory build up as players get closer and closer to their goal and the frustration encountered when they “just miss” achieving their goal may occur not only during scratch card play but also during Candy Crush gameplay. As players make more and more moves, they accrue points and get closer and closer to levelling up. When they run out of moves it is reasonable to assume that frustration will ensue.
To summarize, most current research on near-misses pertains to studies of gambling, limiting their application to the smartphone gaming context. Here we will examine how winning (levelling up), losing, and just failing to win (a near-miss) in Candy Crush affects players’ levels of physiological arousal (as indexed by HR and SCL), emotional reactions (as indexed by subjective ratings) and reward responses (indexed by PRPs). We hypothesize that near-miss outcomes will produce greater physiological arousal (higher HR and SCL) than full loss outcomes during the game. Here, following Stange et al. (in press), we will measure SCL changes that occur during the game as players get closer and closer to levelling up. We expect near-misses to trigger similar SCL changes to actual wins since the anticipatory build up period prior to winning or proximally winning should be comparable. Based on previous findings by Dixon et al. (2013), we hypothesize that players will produce longer PRPs following wins than either regular losses or near-misses. If indeed we see high arousal but small PRPs for near-misses (the aforementioned signature of frustration), we should also see greater subjective ratings of arousal and frustration for near-misses than for losses. Finally, consistent with gambling studies where near-misses trigger the urge to continue gambling, we predict that subjective ratings of urge to continue play will be stronger for near-misses compared to regular losses.