But the tactic had a physical limit. To fit more symbols on the reels, either the symbols had to shrink - making them harder for players to see - or the reels had to get bigger - resulting in an unwieldy machine.
Problem Gambling Research Team, has uncovered other methods that slots designers and casino operators use to keep players on the machines. Video slot machines allow players to place multiple bets on how winning symbols might line up on the screen when the spinning stops.
Microprocessors and random-number generators dictate the outcome. Actual reels have been replaced by digitized "virtual" ones. The advanced slots are more reliable and tamper-resistant than their mechanical ancestors. The computer's versatility means faster, more exciting games, and the possibility of bigger payouts.
The slots all appeared the same, but varied in their "payback percentage" - the portion of a gambler's wager that, on average, the machine is programmed to return. The identical-looking machines had payback percentages ranging from 85 to 98 percent, meaning the casinos kept between.
State gambling regulations, including ones recently drafted for Ohio, permit holds as large as 15 percent on slot machines. It's also not uncommon for regulators to allow a casino to have identical machines with varying holds, as Ontario did.
Virtual reels alter odds of winning With the rise of computer technology in the 1980s, Norwegian mathematician Inge Telnaes devised a brilliant, if devious, solution. In 1984, he patented a revolutionary invention that made it possible for a standard-sized three-reel slot machine to offer the.