Post-reinforcement pauses during slot machine gambling are moderated by immersion.

The post-reinforcement pause (PRP) is an operant effect in which response latencies increase on trials following the receipt and consumption of reward. Human studies demonstrate analogous effects in electronic gambling machines that utilise random ratio reinforcement schedules. We sought to identify moderators of the human PRP effect, hypothesising that the magnitude of gamblers' PRPs is moderated by the type of reinforcing outcome (genuine wins vs. losses-disguised-as-wins [LDWs] vs. free-spin bonus features) and individuals' level of gambling immersion, a cognitive state linked to problem gambling. Experienced slot machine users (N = 53) played a real slot machine for 20 min. The dependent variable was defined as the time delay in the initiation of each bet ("Spin Initiation Latency"; SIL). Using 80% of trials, a linear model was fit regressing SIL on the independent variables (outcome type, immersion, and outcome-by-immersion interaction), and a larger group of covariates (participant ID, trial number, winnings, etc.) selected using double-robust LASSO-regularised regression. The previously unseen 20% of cases were used to validate the model. Positively reinforcing outcome types (wins, LDWs, bonus spins) showed significantly larger SILs than losses, indicating a PRP effect. Immersion did not predict response latencies, but win-by-immersion and LDW-by-immersion interactions indicated that pauses were greater among more immersed participants. The small number of free-spin bonus features showed similar trends that were not statistically significant. These results indicate that gamblers immersed in play remained sensitive to in-game reinforcement (contrary to a prevailing account), and provide guidance for researchers bridging laboratory research and real-world behaviour.

Using machine learning to retrospectively predict self-reported gambling problems in Quebec.

BACKGROUND AND AIMS: Participating in online gambling is associated with an increased risk for experiencing gambling-related harms, driving calls for more effective, personalized harm prevention initiatives. Such initiatives depend on the development of models capable of detecting at-risk online gamblers. We aimed to determine whether machine learning algorithms can use site data to detect retrospectively at-risk online gamblers indicated by the Problem Gambling Severity Index (PGSI). DESIGN: Exploratory comparison of six prominent supervised machine learning methods (decision trees, random forests, K-nearest neighbours, logistic regressions, artificial neural networks and support vector machines) to predict problem gambling risk levels reported on the PGSI. SETTING: Lotoquebec.com (formerly espacejeux.com), an online gambling platform operated by Loto-Québec (a provincial Crown Corporation) in Quebec, Canada. PARTICIPANTS: N = 9145 adults (18+) who completed the survey measure and placed at least one bet using real money on the site. MEASUREMENTS: Participants completed the PGSI, a self-report questionnaire with validated cut-offs denoting a moderate-to-high-risk (PGSI 5+) or high-risk (PGSI 8+) for experiencing past-year gambling-related problems. Participants agreed to release additional data about the preceding 12 months from their user accounts. Predictor variables (144) were derived from users' transactions, apparent betting behaviours, listed demographics and use of responsible gambling tools on the platform. FINDINGS: Our best classification models (random forests) for the PGSI 5+ and 8+ outcome variables accounted for 84.33% (95% CI = 82.24-86.41) and 82.52% (95% CI = 79.96-85.08) of the total area under their receiver operating characteristic curves, respectively. The most important factors in these models included the frequency and variability of participants' betting behaviour and repeat engagement on the site. CONCLUSIONS: Machine learning algorithms appear to be able to classify at-risk online gamblers using data generated from their use of online gambling platforms. They may enable personalized harm prevention initiatives, but are constrained by trade-offs between their sensitivity and precision.

EEG complexity during mind wandering: A multiscale entropy investigation.

Our attention often drifts away from the ongoing task to task-unrelated thoughts, a phenomenon commonly referred to as mind wandering. Ample studies dedicated to delineating its electrophysiological correlates have revealed distinct event-related potentials (ERP) and spectral patterns associated with mind wandering. It remains less clear whether the complexity of the electroencephalography (EEG) changes when our minds wander, a metric that captures the predictability of the time series at varying timescales. Accordingly, this study investigated whether mind wandering impacts EEG signal complexity. We further explored whether such effects differ across timescales, and change in a context-dependent manner as indexed by global and local levels of processing. To address this, we recorded participants' EEG while they completed Navon's global and local processing task and occasionally reported whether they were on-task or mind wandering throughout the task. We found that brain signal complexity as indexed by multiscale entropy decreased at medium timescales in centro-parietal regions and increased at coarse timescales in anterior and posterior regions during mind wandering, as compared to the on-task state, for global processing. Moreover, global processing showed increased complexity at fine to medium timescales compared to local processing. Finally, behavioral performance revealed a context-dependent effect in accuracy measures, with mind wandering showing lower accuracy compared to the on-task state only during the local condition. Taken together, these results indicate that changes in brain signal complexity across timescales may be an important feature of mind wandering.

Do pupillary responses during authentic slot machine use reflect arousal or screen luminance fluctuations? A proof-of-concept study.

Modern slot machines are among the more harmful forms of gambling. Psychophysiological measures may provide a window into mental processes that underpin these harms. Here we investigated pupil dilation derived from eye tracking as a means of capturing changes in sympathetic nervous system arousal following outcomes on a real slot machine. We hypothesized that positively reinforcing slot machine outcomes would be associated with increases in arousal, reflected in larger pupil diameter. We further examined the contribution of game luminance fluctuations on pupil diameter. In Experiment 1A, experienced slot machine gamblers (N = 53) played a commercially-available slot machine in a laboratory for 20 minutes while wearing mobile eye tracking glasses. Analyses differentiated loss outcomes, wins, losses-disguised-as-wins, and (free-spin) bonus features. Bonus features were associated with rapid increases in pupil diameter following the onset of outcome-related audiovisual feedback, relative to losses. In Experiment 1B, luminance data were extracted from captured screen videos (derived from Experiment 1A) to characterize on-screen luminance changes that could modulate pupil diameter. Bonus features and wins were associated with pronounced and complex fluctuations in screen luminance (≈50 L and ≈25L, respectively). However, the pupil dilation that was observed to bonus features in Experiment 1A coincided temporally with only negligible changes in screen luminance, providing partial evidence that the pupil dilation to bonus features may be due to arousal. In Experiment 2, 12 participants viewed pairs of stimuli (scrambled slot machine images) at luminance difference thresholds of ≈25L, ≈50L, and ≈100L. Scrambled images presented at luminance differences of ≈25L and greater were sufficient to cause pupillary responses. Overall, pupillometry may detect event-related changes in sympathetic nervous system arousal following gambling outcomes, but researchers must pay careful attention to substantial in-game luminance changes that may confound arousal-based interpretations.

Investigating Flow State and Cardiac Pre-ejection Period During Electronic Gaming Machine Use.

Flow activities (e.g. sports and gaming) have been associated with positive affect and prolonged engagement. In the gambling field, modern electronic gaming machines (EGMs, including modern slot machines) have drawn concern as a potentially flow-inducing activity that may be associated with gambling-related harms. Current research has heavily relied on self-reported flow, and further insights may be afforded by physiological methods. We present data from three separate experiments in which self-reported gambling flow and cardiac pre-ejection period (PEP; a measure of sympathetic nervous system arousal) were examined. Male undergraduate participants gambled on a genuine EGM in a laboratory setting for a period of at least 15 min, and completed the Flow subscale of the game experience questionnaire (GEQ). Aggregated data were analyzed using multilevel regression. Although EGM gambling was not associated with significant changes in PEP across participants, we found that self-reported flow states were associated with significant decreases in PEP during the first five minutes of EGM use. Thus, participants who experienced flow showed a greater sympathetic nervous system response to the onset of gambling. Though these effects were consistent in experiments 1 and 2, in experiment 3 the effect was inverted during the same time window. We conclude that flow during EGM gambling appears to be associated with early changes in sympathetic nervous system activity, but stress that more research is needed to characterize boundary conditions and moderating factors.

Zoned in or zoned out? Investigating immersion in slot machine gambling using mobile eye-tracking.

BACKGROUND AND AIMS: Immersion during slot machine gambling has been linked to disordered gambling. Current conceptualizations of immersion (namely dissociation, flow and the machine zone) make contrasting predictions as to whether gamblers are captivated by the game per se ('zoned in') or motivated by the escape that immersion provides ('zoned out'). We examined whether selected eye-movement metrics can distinguish between these predictions. DESIGN AND SETTING: Pre-registered, correlational analysis in a laboratory setting. Participants gambled on a genuine slot machine for 20 minutes while wearing eye-tracking glasses. PARTICIPANTS: Fifty-three adult slot machine gamblers who were not high-risk problem gamblers. MEASUREMENTS: We examined self-reported immersion during the gambling session and eye movements at different areas of the slot machine screen (the reels, the credit window, etc.). We further explored these variables' relationships with saccade count and amplitude. FINDINGS: The ratio of dwell time on the game's credit window relative to the game's reels was positively associated with immersion (t(51)  = 1.68, P = 0.049 one-tailed, R2  = 0.05). Follow-up analyses described event-related changes in these patterns following different spin outcomes. CONCLUSIONS: Immersion while gambling on a slot machine appears to be associated with active scanning of the game and a focus on the game's credit window. These results are more consistent with a 'zoned in' account of immersion aligned with flow theory than a 'zoned out' account based on escape.

Interoception and respiratory sinus arrhythmia in gambling disorder.

Gambling has longstanding links with excitement and physiological arousal, but prior research has not considered (a) gamblers' ability to detect internal physiological signals, or (b) markers of parasympathetic functioning. The present study measured interoception in individuals with gambling disorder, using self-report measures and a heartbeat counting task administered at rest. Resting state respiratory sinus arrhythmia (RSA), an index of heart rate variability, was measured as a proxy for parasympathetic control and emotional regulation capacity. In a case-control design, 50 individuals with gambling disorder were compared against 35 controls without gambling problems. Participants completed two self-report measures of bodily awareness and a behavioral test of heartbeat counting. A resting state electrocardiogram (5 min) was used to calculate RSA. There were no significant differences on the self-report or behavioral interoception probes. The group with gambling disorder displayed significantly reduced RSA, which at face value is consistent with reduced parasympathetic control. However, the group difference in RSA did not survive controlling for age and smoking status, as established predictors of heart rate variability. Our findings do not support any changes in interoceptive processing in people with gambling disorder, at least under resting conditions. Our observation that group differences in RSA are partly explained by smoking behavior highlights the importance of controlling for nicotine use in future research characterizing physiological functioning and emotional regulation in disordered gambling.

Effects of bet size and multi-line play on immersion and respiratory sinus arrhythmia during electronic gaming machine use.

Electronic Gaming Machines (EGMs) are regarded as a relatively harmful gambling product, and are associated with psychological immersion (the 'machine zone') and physiological arousal. Specifically, immersion is a phenomenon of attention manifesting as an intense focus on the game at the expense of peripheral stimuli and goals. Past research has indicated significant levels of immersion in response to modern multi-line EGMs when the overall bet is increased, which further scales with risk for problem gambling (Dixon et al., 2014). The present study sought to separate the effects of multi-line play and bet size, on measures of immersion and cardiac activity. Seventy-six male undergraduate students played an authentic EGM on each of 4 pre-defined play strategies while providing electrocardiogram data. The strategies varied the number of paylines and the bet multiplier. From the physiological data, we extracted Respiratory Sinus Arrhythmia (RSA), a marker of task attention derived from heart rate variability. We found that immersion ratings were significantly greater when both paylines and bet-size were high. Importantly, selectively increasing the paylines, but not bet multiplier, produced significant increases in immersion. RSA change indicated parasympathetic withdrawal, consistent with increases in attention during EGM use, but did not differentiate game settings. These results suggest that multi-line EGMs capture attention across a range of play-styles, and that immersion may be effectively amplified by multi-line play.

Measuring the slot machine zone with attentional dual tasks and respiratory sinus arrhythmia.

Recent accounts of problematic electronic gaming machine (EGM) gambling have suggested attentional pathology among at-risk players. A putative slot machine zone is characterized by an intense immersion during game play, causing a neglect of outside events and competing goals. Prior studies of EGM immersion have relied heavily upon retrospective self-report scales. Here, the authors attempt to identify behavioral and psychophysiological correlates of the immersion experience. In samples of undergraduate students and experienced EGM users from the community, they tested 2 potential behavioral measures of immersion during EGM use: peripheral target detection and probe-caught mind wandering. During the EGM play sessions, electrocardiogram data were collected for analysis of respiratory sinus arrhythmia (RSA), a measure of calming self-regulation governed by the parasympathetic nervous system. Subjective measures of immersion during the EGM play session were consistently related to risk of problem gambling. Problem gambling score, in turn, significantly predicted decrements in peripheral target detection among experienced EGM users. Both samples showed robust RSA decreases during EGM play, indicating parasympathetic withdrawal, but neither immersion nor gambling risk were related to this change. This study identifies peripheral attention as a candidate for quantifying game immersion and its links with risk of problem gambling, with implications for responsible gambling interventions at both the game and venue levels. (PsycINFO Database Record

Chronic atomoxetine treatment during adolescence does not influence decision-making on a rodent gambling task, but does modulate amphetamine's effect on impulsive action in adulthood.

In addition to the symptoms of inattention, hyperactivity, and impulsivity, individuals with attention deficit hyperactivity disorder exhibit impaired performance on tests of real-world cost/benefit decision-making. Atomoxetine, a nonstimulant drug approved for the treatment of attention deficit hyperactivity disorder, is a selective norepinephrine reuptake inhibitor administered chronically during adolescence, a time during which the frontal brain regions necessary for executive function undergo extensive maturation. This treatment protocol can affect behavior well into adulthood, but whether it produces long-term changes in complex decision-making has not been investigated. Twenty-four Long-Evans rats were administered saline or 1.0 mg/kg atomoxetine daily from postnatal day 40 to 54. Two weeks after treatment, the adult rats were trained and assessed on the rodent gambling task, in which the animals chose from four options varying in reward, punishment, and uncertainty. Impulsive action was also measured by recording the number of premature responses made. Regardless of the treatment administered during adolescence, rats learned to favor the advantageous options characterized by small, low-penalty rewards in lieu of the larger, higher-penalty reward options. Rodent gambling task performance was then assessed following acute treatment with atomoxetine (0.1-1.0 mg/kg) and amphetamine (0.3-1.5 mg/kg). Across groups, the highest dose of atomoxetine impaired decision-making and decreased premature responding at all doses tested. Amphetamine also impaired choice performance, but selectively increased impulsive action in rats that had previously received atomoxetine treatment during adolescence. These findings contribute to our understanding of the long-term effects associated with chronic adolescent atomoxetine exposure and suggest that this treatment does not alter decision-making under conditions of risk and uncertainty in adulthood.

Games in the Brain: Neural Substrates of Gambling Addiction.

As a popular form of recreational risk taking, gambling games offer a paradigm for decision neuroscience research. As an individual behavior, gambling becomes dysfunctional in a subset of the population, with debilitating consequences. Gambling disorder has been recently reconceptualized as a "behavioral addiction" in the DSM-5, based on emerging parallels with substance use disorders. Why do some individuals undergo this transition from recreational to disordered gambling? The biomedical model of problem gambling is a "brain disorder" account that posits an underlying neurobiological abnormality. This article first delineates the neural circuitry that underpins gambling-related decision making, comprising ventral striatum, ventromedial prefrontal cortex, dopaminergic midbrain, and insula, and presents evidence for pathophysiology in this circuitry in gambling disorder. These biological dispositions become translated into clinical disorder through the effects of gambling games. This influence is better articulated in a public health approach that describes the interplay between the player and the (gambling) product. Certain forms of gambling, including electronic gambling machines, appear to be overrepresented in problem gamblers. These games harness psychological features, including variable ratio schedules, near-misses, "losses disguised as wins," and the illusion of control, which modulate the core decision-making circuitry that is perturbed in gambling disorder.