要旨
Given the option, humans and other animals elect to distribute their time between work and leisure, rather than
choosing all of one and none of the other. Traditional accounts of partial allocation have characterised behaviour on a
macroscopic timescale, reporting and studying the mean times spent in work or leisure. However, averaging over the
more microscopic processes that govern choices is known to pose tricky theoretical problems, and also eschews any
possibility of direct contact with the neural computations involved. We develop a microscopic framework, formalized as
a semi-Markov decision process with possibly stochastic choices, in which subjects approximately maximise their
expected returns by making momentary commitments to one or other activity. We show macroscopic utilities that arise
from microscopic ones, demonstrate how facets such as imperfect substitutability can arise in a more straightforward
microscopic manner, and consider extensions to satiation and fatigue.
