GeistHaus

Personality / Capacities

Capacity for Mentalization

When a friend doesn’t text back, you might think “She’s angry with me,” or “She’s probably swamped,” or “I don’t know yet.” Mentalizing is the capacity behind that last, quietly sophisticated thought: understanding behavior, your own and other people’s, in terms of the needs, feelings, beliefs, and intentions behind it, while remembering that minds are not fully visible from outside.

The PDM-3 defines mentalization as the ability to infer and reflect on one’s own and others’ subjective states. It calls this activity both imaginative, since we imagine what others think and feel, and reality-based, since reasonable accuracy is essential for getting along with people. Most of it happens preconsciously, outside the focus of attention. It helps us describe and express our inner lives, regulate feelings, keep a coherent sense of self, read others accurately, correct our mistakes, and consider alternative explanations instead of seizing on the first one that comes to mind (Lingiardi, Muzi, & Bornstein, 2026, pp. 716–717). Quoting Allen, Fonagy, and Bateman, the manual describes it as a way to “keep in mind the mind” and to see oneself from the outside and others from the inside (p. 717).

Mentalizing is not only verbal; it can show in tone, gesture, and the body. It also shapes whom we trust to teach us things, which the PDM-3 calls epistemic trust (p. 717). Everyone’s mentalizing dips when they are frightened, furious, or in love, so this capacity describes how well and how reliably a person does it, not whether they ever lose it.

Across the Range

The PDM-3 offers three anchor points on its five-point scale (Lingiardi et al., 2026, pp. 717–718). Ratings of 4 and 2 fall between them.

5: Healthy
The person forms reasonably accurate models of their own and others’ minds and can reflect on feelings, thoughts, desires, and needs, even when challenged or distressed. They distinguish inner from outer reality, have insight into their own motives, and think about people in nuanced ways. Healthy mentalizing includes care for others and humility: some confidence in reading minds, along with awareness of how much can never be fully known.
3: Mild to moderate difficulties
The person can usually understand actions in terms of mental states and infer what others are experiencing. Under conflict, distress, or intense arousal, though, awareness of minds drops noticeably. Feelings are hard to elaborate, explanations turn to external justifications, and wishes and feelings may be acted out or expressed through the body. In a safe relationship, some people at this level can recognize these limits.
1: Major to severe difficulties
The person has great difficulty inferring or reflecting on their own feelings or symbolizing other people’s mental states, and trouble telling inner reality from outer reality. What exists in the mind may be taken to exist “out there,” and vice versa. Others’ actions are often confusing or misread, beliefs are rarely revised, and the person may stay embedded in a feeling without words for it. Under stress, the self may feel incoherent, depleted, or absent.

How It Develops

The PDM-3 locates the foundation of mentalizing in early relationships. A “psychological self” develops as an infant takes in a caregiver’s attitude that the baby is a person with a mind. Caregivers do this by taking the child’s perspective, appreciating that minds are separate, treating the child as an agent whose actions have reasons, and making sense of the baby’s intense, nonverbal feelings. Attuned caregiving builds the capacity; caregiving low in empathy or mentalizing can foster distortions, including overinterpretation of mental states, or a mentalizing capacity that breaks down easily under stress (Lingiardi et al., 2026, p. 717). Children also learn through a parent’s mirroring of their feelings that they are recognized and that their emotions can be contained, and much parental mentalizing is implicit, shown in turn-taking and matching expressions rather than in words (pp. 746–747).

Peter Fonagy and his colleagues describe a developmental sequence. Young children begin in a mode of “psychic equivalence,” in which inner and outer reality are treated as the same. Around age 2 comes a “pretend mode,” in which inner life is decoupled from reality but not yet governed by it. Around ages 4 or 5, the two are integrated, and fantasy is clearly distinguished from fact (McWilliams, 2011, p. 26).

Adolescence brings abstract and hypothetical thinking, more mentalizing language, and, by the late teens, a genuine curiosity about other minds, along with new vulnerabilities. Teenagers may project their own states onto others or build overly convoluted inferences from a few social cues. Mentalization may also be defensively inhibited when thinking about the intentions of neglectful or frightening figures would itself be painful (Tanzilli & Malberg, 2026, pp. 421–423). Recent theory describes mentalizing as having four polarities: automatic or controlled, internal or external, focused on self or others, and cognitive or affective (p. 421). In later life, some people who mentalized well earlier become still better at it, drawing on knowledge and experience, while the threats of illness and mortality can reduce access to symbolic thought (Del Corno & Plotkin, 2026, p. 909).

How It Shows Up in Personality

People at the healthy and neurotic levels, asked to describe important people such as parents or lovers, tend to give multifaceted portraits that appreciate each person’s complexity (McWilliams, 2011, p. 57). McWilliams (2011, p. 64), drawing on Fonagy, describes people organized at the borderline level as often lacking reflective function, the capacity to find meaning in their own and others’ behavior, which shows up when they are asked to describe the important people in their lives.

Among styles, the PDM-3 links mentalizing difficulties most closely to the emotionally dysregulated style. People with this style may misread others through projection or assume that others think and feel as they do. Under distress they may see people in all-good or all-bad terms, and their explanations of behavior may be naive and stereotyped or unduly suspicious (McWilliams & Shedler, 2026, p. 697). People with a paranoid style struggle to put themselves in others’ shoes, a problem the manual describes in terms of mentalization (p. 692). People with a somatizing style may lack what Elliot Jurist calls “mentalized affectivity,” the capacity to reflect on one’s own feelings (p. 684).

Mentalizing can fail in two directions. Researchers developing the Reflective Functioning Questionnaire distinguish hypomentalizing, concrete thinking that cannot consider complex models of minds, from hypermentalizing, which builds elaborate models of minds without evidence to support them (Fonagy et al., 2016). The PDM-3’s 1 anchor includes both: an inability to represent minds, and long, overly detailed accounts of minds with little relation to observable reality (Lingiardi et al., 2026, p. 718). People with a narcissistic style have been studied for their attachment and mentalizing patterns as well (McWilliams & Shedler, 2026, p. 689).

How Different Thinkers See It

Fonagy and Target

Peter Fonagy and his colleagues, drawing on attachment research and psychoanalysis, developed the theory of mentalization on which the PDM-3 draws, tracing it to the caregiver’s capacity to hold the child’s mind in mind. With Steele and Steele, Fonagy and Target created the Reflective Functioning Scale, which rates passages of the Adult Attachment Interview on an 11-point scale, from negative or “antireflective” (−1) to exceptional reflective functioning (9). Some interview questions merely permit reflection; others demand it (Lingiardi et al., 2026, pp. 734–735). In the PDM-3’s words, reflective functioning is how mentalization is measured (p. 717).

Bateman and mentalization-based therapy

With Bateman, Fonagy developed mentalization-based therapy, which McWilliams names alongside Kernberg’s transference-focused psychotherapy as one of the best-known research-tested psychoanalytic treatments for borderline-level personality (McWilliams, 2011, p. 71).

Allen

J. G. Allen’s collaboration with Fonagy and Bateman, Mentalizing in Clinical Practice (2008), gave the concept some of its most memorable phrasing, such as understanding misunderstandings and attributing a quality of mind to things (Lingiardi et al., 2026, pp. 717, 740).

Theory of mind and Klein

McWilliams notes that mentalization resembles what philosophers call “theory of mind” and what Melanie Klein called the depressive position: the appreciation that others have separate subjective lives (McWilliams, 2011, p. 26). The psychoanalytic version emphasizes feeling as well as thinking, and the relationships in which the capacity grows.

Epistemic trust

More recent work by Fonagy and colleagues ties mentalizing to epistemic trust, a willingness to treat what others communicate as relevant and trustworthy. The PDM-3 places the assessment of epistemic trust under the capacity for trust, empathy, and intimacy, but notes that mentalizing is vital to it (Lingiardi et al., 2026, pp. 717, 723).

Examples

“She’s just a regular mother”

McWilliams describes how people organized at the borderline level often answer a request to describe an important person. Instead of a three-dimensional portrait, they offer a flat or dismissive one; she gives “My mother? She’s just a regular mother, I guess” as a typical response. She links this to Fonagy’s observation that such clients lack the reflective function that finds meaning in their own and others’ behavior.

Nancy McWilliams, Psychoanalytic Diagnosis (2011), p. 64

Grace learns to read her suitors

In a PDM-3 case illustration, Grace, a strikingly beautiful 48-year-old, was inundated with dating invitations after a breakup and felt obliged to be nice to every suitor. No one had ever helped her understand how others respond to beauty, deal with envy, or tell men interested in her as a person from those interested in her as “arm candy.” Talking about this with her therapist seemed to increase her capacity to mentalize, and she began choosing rather than waiting to be chosen. She was rated 3 on this capacity.

Lingiardi & McWilliams (Eds.), PDM-3 Online Supplement (2026), pp. 47–49, 53

Emilia revises a belief about her daughter

Emilia, 84, had long believed that her daughter was still angry with her, did not love her, and preferred her mother-in-law. Over the course of brief therapy she acknowledged her own jealousy and came to recognize that her daughter was no longer angry; otherwise, Emilia reasoned, her daughter would hardly be inviting her to live in her home. Emilia was rated 4 on mentalization.

Lingiardi & McWilliams (Eds.), PDM-3 Online Supplement (2026), pp. 41, 43

History

The first PDM (2006) had no mentalization category. Its nearest neighbors were the “capacity to form internal representations” and the “self-observing capacity” (Stern, 2009); this mapping is ours, not the manual’s. The PDM-2 introduced the “capacity for mentalization and reflective functioning” (Gori et al., 2025), and the PDM-3 shortened the name to the capacity for mentalization (Lingiardi et al., 2026, p. 711).

The rise reflects the influence of Fonagy and colleagues’ work in the 1990s and 2000s, including their 1998 Reflective Functioning manual and their 2002 book on affect regulation and mentalization, both cited in the PDM-3 (Lingiardi et al., 2026, pp. 734, 742). In a study of 285 psychotherapists describing patients with Cluster B personality disorders, mentalization emerged as the most central and influential of the PDM-2’s 12 capacities (Gori et al., 2025). The PDM-3 also reports that higher mentalizing capacity was associated with better outcomes in a study of eating disorder treatment (Lingiardi & McWilliams, 2026a, p. 12).

Sources