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.