Why Do People Gamble and Keep Gambling despite Heavy Losses?

If a long series of gambles is subjectively structured into units each consisting of a string of consecutive losses followed by a win, positive valued strings will be short and negative valued strings will be long. Long negative strings will be temporally discounted more than short positive strings, increasing the gamble's subjective value. People, therefore, may gamble because even games of objectively negative expected value may be subjectively positive. People may keep gambling despite heavy losses because reduction of degree of discounting and expansion of the behavioral unit, characteristics of self-control in other areas, fail to significantly decrease a gamble's subjective value.