Fig 1. Hypothesized dyadic version of the Health Action Process Approach in couples where one’s own volitional processes predict better own health behavior (actor effects represented with solid lines) and one’s partner’s volitional processes predict better own health behavior (partner effects represented with dashed lines).

Note: The conceptual model is based on the Actor-Partner Interdependence Model (APIM; [24]) depicting two dyad members, Partner A and Partner B, with predictors and outcome for each member. The dyadic models were calculated separately for each volitional predictor.