Temporal (or delay) discounting occurs when rewards are valued differently relative to each other based on points in time. For example, would you rather receive $100 today or $130 a month from today? This presents people with larger later vs. smaller sooner reward options. Present rewards tend to be valued more than future rewards, given two similar rewards. Humans are said to discount the value of the later reward. This trend is related to impulsivity and immediate gratification in self-control research. Some research (the hyperbolic discounting theory) has found that discounting does not occur at a constant rate across time. When both rewards are in the distant future (e.g. one year vs. one year and a month) the values placed on rewards decreases slower, that is people tend to wait for the larger reward. However, valuations fall rapidly for rewards in the near future (e.g., now vs. one week).