What does IDI measure? Three dimensions and the research behind them

Every tool that describes how people behave makes a choice, usually without saying so: which dimensions should behavior be described in? That choice decides what shows up in the result and what does not.

IDI (Interpersonal Dynamics Inventory) describes social interaction at work with three dimensions: Affiliation, Directiveness and Adaptability. This article sets out where they come from, how they are defined and where their limits lie.

Two axes the research keeps returning to

The first two dimensions are grounded in the interpersonal circumplex, a model developed by Timothy Leary (1957) and Jerry Wiggins (1979). The circumplex arranges interpersonal behavior along two axes: one about closeness and warmth, and one about influence and control. Interpersonal psychology has repeatedly identified this structure as the most stable way to describe how people perceive each other's behavior.

The structure has not weakened under scrutiny. In current research the two axes are usually called communion and agency, what Andrea Abele and Bogdan Wojciszke (2014) describe as the two fundamental dimensions of social perception, often called the "Big Two". If anything, later work has strengthened their standing.

A parallel line of research has reached the same conclusion from another direction. Susan Fiske and her colleagues have shown that warmth and competence are the two enduring dimensions of how we judge other people and groups (Cuddy, Fiske & Glick, 2008; Fiske, 2018).

IDI's Affiliation corresponds to the interpersonal expression of communion, and Directiveness to the interpersonal expression of agency.

A conceptual match, not an exact one

The correspondence between IDI and the broad fundamental dimensions is conceptual rather than exact, in two respects.

The first is scope. Agency and communion span the whole of personality and can even be recovered from the five-factor model, the Big Five (Entringer, Gebauer & Paulhus, 2022). IDI measures something narrower: their specifically interpersonal, context-bound form. What it describes is how a particular individual is perceived to behave by particular respondents in a shared work context, not a stable trait of the person.

The second is how the axes relate to each other. IDI treats Affiliation and Directiveness as conceptually distinct, not as statistically fully independent. In practice the dimensions are partly related, and impressions of communion and agency can covary in non-linear ways (Imhoff & Koch, 2017). But they mean different things, and it is this conceptual distinctness, repeatedly validated across interpersonal measures (Locke, 2000; Hopwood, 2018; Pincus, Hopwood & Wright, 2020), that the IDI structure rests on.

Affiliation: relationships or tasks

Affiliation is defined as the degree of orientation towards interpersonal closeness and relationship building in a given work context.

A high score means respondents perceive the individual as relationship-oriented: someone who invests in personal contact, creates a sense of safety and prioritizes cohesion. A low score means the individual is perceived as task-oriented: someone who focuses on the issues at hand, builds trust through competence rather than personal closeness and keeps interaction professionally bounded.

The dimension is not a value judgment. Both ends describe patterns of behavior that work well in some contexts and less well in others.

Directiveness: setting direction or giving room

Directiveness is defined as the degree of taking influence and setting direction in a given work context.

A high score means the individual is perceived as the one who takes initiative, drives decisions and shapes the situation. A low score means the individual is perceived as the one who listens, gives others room and contributes through reflection rather than steering.

The same value neutrality applies. High Directiveness is not the same as better leadership. It is a pattern of behavior that is effective when a situation calls for clarity and pace, and that can be counterproductive when it calls for reflection and broad buy-in.

Adaptability: a third dimension

The two axes of the circumplex describe what a person does, whether they seek closeness or distance and whether they take up space or give it. They say nothing, however, about whose perspective drives the behavior. That gap is why Adaptability emerged as a third dimension in IDI's own research.

Adaptability is defined as the degree to which attention shifts between one's own needs and the needs of others in a given interaction. A high score means respondents perceive the individual as accommodating: someone who checks in, adjusts and prioritizes the needs of others. A low score means the individual is perceived as steadfast: someone who holds their line, communicates their own needs clearly and is predictable in their behavior.

This orientation has a conceptual parallel in later interpersonal research. Vicki Helgeson and Heidi Fritz (2000) distinguished between a focus on the self to the exclusion of others and a focus on others to the exclusion of the self. They treated the direction of attention, towards one's own or others' needs, as a dimension of its own, separable from warmth and dominance. Later work has supported that distinction: orientations towards the self and towards others appear as distinct individual differences with their own outcomes, not as restatements of agency and communion (Helgeson & Palladino, 2012).

Adaptability is not another point on the circumplex but a separate dimension. It is measured with the same method, from the same respondents and in the same context as the other two, and that is what makes it a genuine third dimension rather than an add-on.

Adapting is not the same as being changeable

The most important distinction for Adaptability is the one between adjustment and variability. What the dimension captures is functional flexibility: the ability to read a situation and adapt to what it requires (Paulhus & Martin, 1988). That is not the same as behaving differently from one time to the next.

The research draws that line sharply. The ability to fit one's response to the situation, to be sensitive to context, to have a repertoire of responses and to take in feedback, is associated with better adjustment, not worse (Bonanno & Burton, 2013). A meta-analysis of coping flexibility shows the same thing: it is the fit between response and situation that predicts good adjustment, while indiscriminate variability predicts considerably less (Cheng, Lau & Chan, 2014).

The reverse also holds. Indiscriminate swings in interpersonal behavior, variability that is not guided by what the situation requires, are associated in research with poorer social functioning. Large shifts in how much warmth and dominance a person expresses from one interaction to the next, sometimes called interpersonal "spin", are a sign not of responsiveness but of instability (Moskowitz & Zuroff, 2004). The costs are concrete: people who shift style indiscriminately tend to have more distant relationships at work and meet lower satisfaction and more avoidance from their coworkers (Côté, Moskowitz & Zuroff, 2012).

High Adaptability in the IDI sense therefore does not mean being changeable, and a low score is not a shortcoming to be corrected. The dimension separates calibrated adjustment from inconsistency, and it credits only the former.

No end of the scale is better

Like the other two dimensions, Adaptability is value-neutral. Steadfast behavior offers predictability and a clear sense of where a person stands. Accommodating behavior offers responsiveness. Each works in some contexts and limits in others.

What you do, and for whose sake

Taken together, IDI rests on two axes that research on social perception has returned to for almost seventy years, and on a third that captures what those two cannot show. Affiliation describes whether you seek closeness or keep your distance. Directiveness describes whether you take up space or give it. Adaptability describes whether your attention is on your own needs or on those of others.

None of the dimensions says who you are, and none of them ranks behavior. They describe how you are perceived by the people you work with, in the context you share. Whether a behavior works is decided by the situation, not by the scale.

Two dimensions describe what you do. The third describes for whose sake.