Psychological Flexibility

Psychological Flexibility

Psychological flexibility is the capacity to stay in contact with difficult internal experience, thoughts, feelings and sensations, without being controlled by it, and to keep acting in the direction of what you value. It is the central process construct of acceptance and commitment therapy, and it belongs to Steven Hayes. The construct has a developed measurement literature, a mediation literature showing that it accounts for outcome change in trials, and a substantial body of randomised evidence behind the therapy built on it. Nothing in this entry is clinical guidance.

What it is

The construct is about the relationship a person has to their own internal experience rather than about the content of it. The aim is not to feel less, or to dispute a thought until it goes away, but to hold thoughts and feelings loosely enough that they stop dictating behaviour, while action continues in the direction of what the person values.

Steven Hayes is the originator, and acceptance and commitment therapy is the treatment built on it. The technique sitting most directly underneath the construct is cognitive defusion, which changes a person's relationship to a thought rather than arguing with its content.

The canonical review, and the source to reach for, is Todd Kashdan and Jonathan Rottenberg's "Psychological Flexibility as a Fundamental Aspect of Health", published in Clinical Psychology Review in 2010. It is the right place to start for what the construct predicts and how it is measured.

In effect

The construct travels well into popular writing, and its attribution usually does not. Benjamin Hardy defines it closely and accurately at page 121 of Personality Isn't Permanent, as being in touch with your emotions without being absorbed by them while actively pursuing meaningful goals. That is a fair rendering. Neither Hayes nor acceptance and commitment therapy is named anywhere in the book, in the body text, the endnotes or the acknowledgements.

The Kashdan and Rottenberg review is in the book, which is more than most trade treatments manage. It is the single note keyed to the construct, and it sits at page 49, roughly seventy pages before the discussion that actually needs it. The endnotes are keyed by page number and a catchphrase with no markers in the body text, so a reader at page 121 has no signal that a note exists, and a reader who does go looking will find nothing there.

Both sides are worth stating. Popularising a clinical construct without an academic apparatus is normal in the genre, and the right review was cited. Against that, a term of art arrives carrying the authority of a research literature while the literature's originator, its therapy and its trial base are all absent, so the reader receives the credibility with no route to the evidence. The construct is sound, the definition given is accurate, and the attribution is the problem. Cite Hayes for the construct and Kashdan and Rottenberg for the review.

What it does not say

It does not say that difficult feelings should be suppressed or reframed away. The construct is defined against that, and the distinction between changing a thought's content and changing a person's relationship to it is the whole of it.

It does not carry across to every claim made in its name. A popular account that borrows the term while omitting the therapy and its trials is borrowing credibility, not evidence.

It does not establish any of the claims it is paired with in popular writing, including claims about how quickly a feeling should pass or about how a feeling hardens into a trait.

It does not contain instructions. No technique is described here, and anyone considering treatment needs a clinician rather than an entry.

Sources

  1. Kashdan, T. B., & Rottenberg, J. (2010). "Psychological Flexibility as a Fundamental Aspect of Health." Clinical Psychology Review, 30, 865-878. The correct review to cite for the construct.
  2. Hayes, S., for the construct and for acceptance and commitment therapy. Named for attribution; no specific work was consulted for this entry, so no year is given.
  3. Hardy, B. Personality Isn't Permanent. p. 121 for the definition, given without credit; pp. 49 to 50 for the earlier use and the single keyed note. Hayes and the therapy are named nowhere in the book.
  4. Evidence review. Verdict: robust, on the strength of the therapy's literature rather than of any popular source.