The theory on which this technique is based is one of circular causality: there is an assumption that human behaviour can best be understood from a point of view that regards actions as both responses to other actions and the triggers for further actions.

While it is possible to describe behaviour so as to show a linear connection between cause and effect:

"She is ‘mad’ because this is the only way she can show her anger towards her parents"

...a circular construction is less likely to lead to ideas of blame, and more likely to enable families to alter their interactions and belief systems:

"Regardless of who ‘first’ had the problem, even if it were possible to establish that, the whole family can be seen as caught in a circular loop whereby symptomatic behaviours lead to carers’ responses, such as high levels of criticism, that in turn reinforce those same symptoms, which in turn lead to more critical responses on the carers’ part, and so on..."

How to do circular interviewing:

The practice of interviewing follows a circular (or spiralling) pattern, where the feedback to the KW's question will influence and shape the KW's next question, and so on.

This is a purposive and responsive interviewing style: Purposive... because the KW is central as the primary asker of questions. Yet responsive to feedback and openings offered by the various family members.

In this way both KW and family together can construct a new understanding of the situation. Circular interviewing involves a particular interest in questions of difference, since it is through the perception of difference that we construct new information, and different perceptions of self and others become possible.

There are a variety of questioning techniques which make it possible for KW and family to explore issues of difference and the definition of relationships, such as:

Comparison questions

"Were you closer before or after he became psychotic?"

Ranking questions

Who would be most surprised if she stopped being low and withdrawn?" "...Who the second-most?" etc

Triadic questions

One person is asked to comment on the relationship between the two others, e.g. "When her father got ill, did your mother become closer to her father or more distant?" The answer to questions such as these will stimulate further exploration, e.g. by asking another family members to comment on the answer of the first one, and then exploring differences or similarities in their perceptions of relationships and events etc.

By participating in such an interview the family members perceive themselves through the eyes of the other; not only may they hear other people's views differently, but also their own views, expressed in this context, may look different to them. The links between this style of questioning and Mentalization are obvious.

Thus for the KW and the family, their interest and curiosity about one another remains stimulated, and changed perceptions of actions or relationships may lead to new and different behaviours and relationships, as well as a re-examination of belief systems which had to date been held with firm conviction.

Hypothetical questions

A special sub-category of this style of questioning is known as hypothetical questions. These are particularly useful when individuals or couples are locked in a rigid stance of blaming about who is "at fault" or "ill" and who is not. In the face of such a stuck interactional pattern the KW can proceed via an "as-if" stance, which makes it possible to consider change in fantasy, even if it does not - yet - seem possible in reality.
These are a particular form of hypothetical questions, where couples are invited to project current relationship patterns and problems into the future, and consider the effects of such lack of change on their future lives:

"So if you continue to argue in this way about James coming home late for the next week, do you see anything changing? ...What about for the next couple of months? for the next 2 years?..."

Aim of circular questioning

The effect of circular questioning is to invite the family's curiosity about the history, context and pattern of their unsatisfactory interactions, which includes any psychiatric disorder and associated symptoms. Just as the KW gains an understanding of how these interactions fit together to result in a relationship pattern which is stressful to the family, so the aim is to help the family members themselves see their situation differently, make new connections, and see new opportunities for change and flexibility.

Another effect of circular interviewing is to disrupt and perturb set patterns of thinking and action, functioning as an intensive but contained challenge to the family's previously held views. Thus while overtly it may seem less challenging than some more directive techniques (see under Challenging techniques), it tends to have similar effects, namely of altering set balances in relationships by interrupting habitual patterns.