Slots are arguably the most popular casino games. They’re flashy, offer multiple incentives to players and can provide countless hours of entertainment. They also vary in their pay-outs, volatility and features. So how do players choose the right machine for them? The answer is based on their personal preferences and gaming habits.

The first slots machines were introduced in the 19th century. They were operated in saloons and were not regulated, with purchase and payout (usually in drinks and cigars) taking place surreptitiously across a counter. However, forces of morality and the clergy increasingly opposed their operation and by the end of the ’20s many states had banned them except for private social clubs.

In the 1950s electromechanical sensors replaced mechanical slides and allowed for new types of payout schemes, including diagonal and multiple coin multipliers. Microprocessors also enabled manufacturers to assign a different probability to each symbol on each reel, so that it might appear that a winning symbol was close even though the odds were against it.

Dixon et al. (2019) showed a correlation between dark flow and enjoyment during slots play, but the measures they used were not designed to distinguish between reward reactivity and enjoyment attributable to dark flow. This study builds upon their findings by analyzing the effects of reward reactivity on enjoyment during slots. To do this, we measured the pressure of each spin button press using a force transducer fixed underneath each of three separate slot simulators housed in a single cabinet. The force was converted to a volt signal that was recorded by an AD Instruments PowerLabs device and saved in Labchart.