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	Ego Depletion Paradigm	Within-Subjects Factorial Design
Field	Social Psychology	Social Psychology
Family	Process / pipeline	Process / pipeline
Year of origin	1998	2004
Originator	Roy Baumeister and colleagues	Experimental-design tradition (widely used in social psychology)
Type	Sequential-task experimental paradigm	Experimental design framework
Seminal source	Baumeister, R. F., Bratslavsky, E., Muraven, M., & Tice, D. M. (1998). Ego depletion: Is the active self a limited resource? Journal of Personality and Social Psychology, 74(5), 1252-1265.	Kahneman, D., Krueger, A. B., Schkade, D. A., Schwarz, N., & Stone, A. A. (2004). A survey method for characterizing daily life experience: The Day Reconstruction Method. Science, 306(5702), 1776-1780.
Aliases	Self-Control Depletion Paradigm, Dual-Task Self-Control Paradigm, Strength Model Paradigm	Repeated-Measures Factorial Design, Within-Participants Factorial, Crossed Within-Subjects Design
Related	3	2
Summary	The ego depletion paradigm, introduced by Baumeister, Bratslavsky, Muraven, and Tice in 1998, tests the strength model of self-control, which holds that acts of self-regulation draw on a limited, shared resource that becomes temporarily depleted with use. In the classic dual-task design, participants first perform a task requiring self-control -- such as resisting tempting food, suppressing emotion, or overriding a habitual response -- or an equivalent task without such demands, and then perform a second, unrelated self-control task. The prediction is that those who exerted self-control on the first task perform worse on the second, exhibiting ego depletion. The 1998 demonstrations were highly influential and generated a vast literature, but large-scale replication efforts in the 2010s yielded weak or inconsistent results, making ego depletion a central case in debates about replicability and prompting theoretical revisions and stricter methodological standards.	The within-subjects factorial design is an experimental framework in which each participant is exposed to every combination of two or more manipulated factors, allowing researchers to test the main effect of each factor and their interactions while using each person as their own control. Because the same individuals experience all conditions, between-subject differences are removed from the error term, giving within-subjects factorial designs substantially greater statistical power and efficiency than between-subjects designs for the same number of participants. This makes them a workhorse of experimental social psychology, especially for reaction-time, judgment, and affect studies where many trials per person are feasible. The design's power comes with the need to control order and carryover effects through counterbalancing, and to analyze the data with repeated-measures or mixed-effects models that respect the non-independence of observations from the same person.