Apart from the uncertainty about whether an agency will deliver a future reward at all, there is also the expenditure of resources in keeping track of and following up on a debt. If you have to keep track of a debt for a year, and take action to claim it at the end of that time, that could very well cost more than $50 worth of time and energy, particularly when you take into account the need to spend resources retaliating if the debtor fails to pay. I think it is much more plausible that people use ad hoc heuristics developed to deal with these issues, than that we actually use a hyperbolic discount function.
… as, according to the paper you linked, do rats. Good point. Can this be explained in similar ways? A pigeon or rat’s environment could surely provide uncertainty about whether a future reward will be delivered at all. Time and energy spent keeping track of a future reward might still be a significant cost. Could these factors have selected for neural circuits that just apply a hyperbolic discount function as a default in the absence of specific reason to do otherwise? This does seem to be evidence suggesting the answer might be yes.
Naturally-occurring cases where hyperbolic discounting leads to suboptimal solutions are relatively rare, and at least one seems to have evolved a patch.
I think it is much more plausible that people use ad hoc heuristics developed to deal with these issues, than that we actually use a hyperbolic discount function.
Those issues seem pretty common. Why would nature not use hyperbolic discounting—and then use ad hoc heuristics to patch it in cases where it doesn’t apply?
Yeah, the paper Yvain linked, seems to be providing evidence that a hyperbolic discount function may be the first-order heuristic for handling such issues, with patches applied where appropriate.
Apart from the uncertainty about whether an agency will deliver a future reward at all, there is also the expenditure of resources in keeping track of and following up on a debt. If you have to keep track of a debt for a year, and take action to claim it at the end of that time, that could very well cost more than $50 worth of time and energy, particularly when you take into account the need to spend resources retaliating if the debtor fails to pay. I think it is much more plausible that people use ad hoc heuristics developed to deal with these issues, than that we actually use a hyperbolic discount function.
Pigeons also discount hyperbolically.
… as, according to the paper you linked, do rats. Good point. Can this be explained in similar ways? A pigeon or rat’s environment could surely provide uncertainty about whether a future reward will be delivered at all. Time and energy spent keeping track of a future reward might still be a significant cost. Could these factors have selected for neural circuits that just apply a hyperbolic discount function as a default in the absence of specific reason to do otherwise? This does seem to be evidence suggesting the answer might be yes.
http://lesswrong.com/lw/1ss/babies_and_bunnies_a_caution_about_evopsych/1o4d
Naturally-occurring cases where hyperbolic discounting leads to suboptimal solutions are relatively rare, and at least one seems to have evolved a patch.
Those issues seem pretty common. Why would nature not use hyperbolic discounting—and then use ad hoc heuristics to patch it in cases where it doesn’t apply?
Yeah, the paper Yvain linked, seems to be providing evidence that a hyperbolic discount function may be the first-order heuristic for handling such issues, with patches applied where appropriate.