DITs are used in dyadic interventions in which partners are instructed to interact with each other. A detailed description and classification of different types of dyadic interventions can be found in Di Maio, Villinger, et al. (2024).

We define a DIT to change behaviors as an observable and replicable intervention technique that explicitly involves any form of interaction with, or clear reference to, a non-professional dyad member to change behavior. The technique specifies “who performs what for whom” during intervention delivery or subsequent implementation (Di Maio, Villinger, et al., 2024).

DITs that are performed by one partner alone are called cross-over techniques. For instance, one partner could be instructed to set a healthy nutrition goal for the other partner or for them as a dyad. DITs that are performed by the dyad together are called joint techniques. For instance, the dyad could be instructed to set a physical activity goal for one partner or for them as a dyad.

DITs can instruct either observable interactions (e.g., providing support, giving feedback) or mental representations (e.g., recognizing risks, planning) that are related to the behavioral outcome.