An idea for an experiment:

Sub-part one: Ask participants various questions to determine the minimum value of x for them to agree to the former option in, "Would you rather we give $100+x to a perfect stranger, or $100 to you?". (Initial prediction: values will vary widely, from particularly generous people with an x of -$99.99, to particularly selfish people with an x of infinity.)

Sub-part two: Ask participants various questions to determine the minimum value of y for them to agree to the former option in, "Would you rather we give $100+y to you in 5 years, or $100 to you now?".

Initial prediction: x and y will be closely correlated; the more a person is willing to give money to perfect strangers, the more they'll be willing to give money to their future selves.

Possible variation: Change 'perfect stranger' in sub-part one to people with varying levels of closeness to the participant: distant acquaintance, close friend, family member.

Possible variation: Change '5 years' in sub-part two to different time-scales.

If both variations are included: Then, possibly, the data may converge into a simple shape. Possible complications for that shape may arise from how likely the participant feels they're likely to still be alive in n years; and in how strongly they trust the experimenters to actually distribute the money.

Additional complications: I am completely unaffiliated with any university or other educational institution, have never performed a psychological experiment, and have no budget to perform any such experiment.