Why do people work intermittently and why do they synchronize their wo
rk schedules? A group of interacting workers who differ in tastes is a
nalyzed. A lifetime labor supply model is developed which combines tir
ing, rhythmic changes in the environment and interactions among worker
s, arising from communication and coordination. A multiplicity of sync
hronized equilibria arises. These equilibria can be ranked according t
o the length of the work period. Equilibria with longer hours are pref
erred by all workers in the group. The worker with the highest aversio
n to work sets the standard and others conform to him.