Slot machines are by far the most popular games at online casinos, even though the average return they offer is lower than some other game categories. There are two reasons usually attributed for this. One reason is that slot machines require no skill and the second reason is that they have potential for high payouts. Recent revelations by software providers indicate that there could be a third reason which contributes to a greater extent. Slot machines are visually compelling and they arrest the attention of the online casino player. Software providers now intentionally enhance the visual appeal when they design and develop the slot games.

More and more slot games now begin with an animated introductory clip. This is almost mandatory for branded slot games. Software providers include a provision to skip the introductory clip because the fascination usually wears off after some time. The symbols are often crafted in bright colours and stand out boldly on the reels. Software providers are beginning to pay detailed attention to every aspect that appears on the screen. There integrate the background to the reels, the payline indicators and the operating buttons with the theme of the slot so that a unified visual is presented on the screen. Backgrounds with subtle animations are getting more frequent.

The next set of visuals comes into play when winning combinations are hit. Once upon a time the win animations were restricted to the flashing of the symbols in the winning combination. In some of the latest slot machines the win animations break through from the symbol and encompass the entire screen. Or there are characters standing outside the reels cheering the players for the wins. When players hit big wins with four of five high paying symbols the visual experience is something great. Often there is a shower of gold coins across the screen or something with a similar effect. This is backed by appropriate audio like the cash register ringing in an old fashioned electro mechanical slot machine. The effect is so powerful that players want to experience it again and again and it motivates them to continue wagering.

Brett Jackson, director of game development at Bally Technologies, recently referred to another subliminal factor that compels players to persist wagering on slot machines. He claimed that when players see like symbols falling in place on an active payline the experience stimulates “the pleasure regions of the human brain”. He refers to this psychological enticement as “the machine zone”. Jackson adds that the machine zone is so compelling that it suppresses normal bodily functions and sensations, like hunger, thirst and everyday concerns, so that the player is able to wager for longer periods.