When effort fails: Instances and reasons for effort-performance decoupling.

Across domains, effort is often assumed to support performance, and performance is frequently used to infer effort. However, observed effort-performance relationships are less straightforward than these assumptions suggest, highlighting conditions under which effort and performance can become decoupled. Here, we review four broad factors that contribute to apparent decoupling: (1) system limits, (2) inefficiency and noise, (3) measurement mismatches, and (4) motivational misdirection. We show how these factors can underlie instances of concurrent decoupling (real-time) and prospective decoupling (over time) in the cognitive, as well as in the physical domain. By framing these factors ontologically as structural, statistical, epistemic, and psychological sources of decoupling, we identify commonalities in effort-performance relationships across research fields. We highlight how they can account for apparent non-linearities, including trade-offs and plateaus in the effort-performance relationship. This perspective can serve as a transdisciplinary agenda for studying effort-performance dynamics, helping researchers and practitioners to better describe, report, and understand effort-performance (de)coupling.