How can people learn to make better decisions and be-come more far-sighted? To make the underlying learningmechanisms more accessible to scientific inquiry, we developa computational method for measuring the time course ofexperience-dependent changes in people’s planning strategies.We validated our method on simulated and empirical data: onsimulated data its inferences were significantly more accuratethan simpler approaches, and when evaluated on human datait correctly detected the plasticity-enhancing effect of perfor-mance feedback. Having validated our method, we illustratehow it can be used to gain new insights into the time courseand nature of cognitive plasticity. Future work will leverageour method to i) reverse-engineer the learning mechanismsenabling people to acquire complex cognitive skills such asplanning and problem-solving and ii) measure individual dif-ferences in cognitive plasticity.