On the Marginal Value Theorem

I am still reading Randolph Nesse’s, Good Reasons for Bad Feelings. I got stuck on Chapter 6, “Low Mood and the Art of Giving Up.”

He talks about the Marginal Value Theorem, which is mathematical behavioral ecologist Eric Charnov’s solution presented to a question best imagined by you foraging for berries. At first, the berries are easy and delicious to grab. The more time you spend at a particular bush however, the less accessible the berries become.

At what point do you leave the bush in favour of finding another one?

The question may really be:

When do you give up on a goal, dream, or activity?

Activity could be extended to include a mode of being.

At what point do you let go?

The answer presented by Nesse is this:

“…all the action is at that spot “on the margin” where the rate of getting berries at the current bush dips below the number of berries you can get per hour by moving to a new bush.”

Walking away from anything you love is hard. Easier to weigh the future, that place that doesn’t exist yet. The value in looking ahead is that it allows us to form conceptions of what we want more. Are your hands tired of being bruised when reaching further and further into the bush?