Systemic therapists assume, but have not yet proved that ordinary people: (i) normally do not use triadic thinking and (ii) are able, thanks to therapists' interviewing techniques, to construct triadic explanations. To test these assumptions this study analyses the explanations provided by 400 undergraduates of an unexpected piece of behaviour framed in four stimulus situations where the breadth of the observation field was manipulated. The results show that triadic explanations are unusual and increase with the widening of the field of observation from the monad to the triad. It is the ‘enigmatic’ triadic situation – adding a puzzling discrepancy between the actors' forms of behaviour – that elicits more triadic explanations. This suggests that therapists should explore with clients the contradictions disclosed by the widening of the field of observation and support reframings actively co-constructed with them instead of ‘pre-packaged’ ones.