People’s cognitive strategies are jointly shaped by function and
computational constraints. Resource-rational analysis lever-
ages these constraints to derive rational models of people’s
cognitive strategies from the assumption that people make
rational use of limited cognitive resources. We present a
resource-rational analysis of planning and evaluate its predic-
tions in a newly developed process tracing paradigm. In Ex-
periment 1, we find that a resource-rational planning strategy
predicts the process by which people plan more accurately than
previous models of planning. Furthermore, in Experiment 2,
we find that it also captures how people’s planning strategies
adapt to the structure of the environment. In addition, our ap-
proach allows us to quantify for the first time how close peo-
ple’s planning strategies are to being resource-rational and to
characterize in which ways they conform to and deviate from
optimal planning.