COM-B Model

COM-B Model is a psychological model of behavior developed by health psychologist Susan Michie with Maartje van Stralen and Robert West at University College London, in which capability, opportunity, and motivation interact to generate behavior, and enacted behavior feeds back on those three conditions (Michie, van Stralen, & West, 2011).

What it is

• Capability — the individual’s psychological and physical capacity to engage in the behavior, including the necessary knowledge and skills. Psychological capability covers comprehension, reasoning, memory, attention, and self-regulation; physical capability covers skill, strength, and stamina.

• Opportunity — all factors outside the individual that make the behavior possible or prompt it. Physical opportunity is afforded by the environment (time, resources, access, cues); social opportunity is afforded by the cultural milieu, including language, norms, and social cues.

• Motivation — all brain processes that energize and direct behavior, not only goals and conscious decisions. Reflective motivation involves evaluations, beliefs, intentions, and plans; automatic motivation involves emotions, impulses, and associative learning.

• Interaction and feedback — capability, opportunity, and motivation interact to generate behavior, and enacting a behavior can alter capability, motivation, and opportunity in turn.

Use in nutritional psychology

In nutritional psychology, COM-B is used to analyze eating behavior and design dietary interventions by mapping capability (nutrition literacy, interoceptive awareness, self-regulation), opportunity (food environments, access, social and cultural food norms), and motivation (reflective goals alongside automatic food reward, cravings, and habit) as interacting determinants of what and how people eat.