Brain Scans Used To Replicate Jung’s Word Association Test

A central tenet of CG Jung’s analytical psychology is that the unconscious has drives strong enough to override conscious will. Hence, he stressed ‘listening’ to dreams and fantasies that arise from unconscious stirrings through active imagination and other forms of creative expression. Jung believed listening to the unconscious could increase psychological integration and reduces internal conflict — if not decrease the likelihood of behaving in ways we later regret.

Jung theorized that the unconscious contains complexes, which he described as

… psychic entities which are outside the control of the conscious mind … always contain something like a conflict … are the ‘sore spots’, the bêtes noires, the ‘skeletons in the cupboard’ which we do not like to remember but still come back to mind unbidden in the most unwelcome fashion …. (Jung 1921, paras. 923-27)

Jung also wrote the following about complexes, thus connecting them to a history of trauma:

…the aetiology of their origins is frequently a so-called trauma … [or] … a moral conflict.” (ibid., Jung 1934, para. 204)

Jung believed that when a complex is activated, such as when something in the environment triggers reminders of a past trauma, an internal conflict resulted between the stimulated unconscious content and the equally strong impetus to ignore what was activated. Jung theorized this interaction between activation and repression is at the core of complexes and internal conflicts.

To test his theory of complexes, Jung devised the Word Association Test (WAT), which Leon Petchkovsky and colleagues have reformulated as a fMRI brain scan study (2013, citation below). They describe Jung’s original WAT experiment as follows:

As we know, Jung noticed that when a person presented with a word from a standard list is asked to respond as quickly as possible with the first word that comes to mind, most responses tend to be bland and neutral, but every so often there are long pauses, often with unusual behavioral and semantic features (the so-called ‘complex indicators’), and physiological disturbances (heart rate, breathing rate, skin conductance). Such responses typically organize around themes. From these responses, a ‘map’ of psychological ‘hot spots’ can be built. Jung called these affect-bound thematic nodes the ‘complexes’. But more importantly, both he and Freud viewed complexed reactions as evidence of ‘repression’, a state in which the subject’s experience collides with an internal opposition, generating internal conflict.

Petchkovsky and his colleagues identified a specific activation pattern in the brain that they believe corresponds to the complexes Jung was searching for with his WAT experiment. This pattern begins with high levels of interhemispheric symmetry (for about 3 seconds) before the activation shifts to right hemispheric dominance. Petchkovsky and colleagues explained this shift in terms of research on the brain unavailable to Jung when he conducted the WAT experiment:

The right hemisphere develops first (the first 2 to 3 years of life) and processes incoming data (including proprioceptive ‘body field’) holistically and emotionally. It mediates highly affect-loaded attachment and threat patterns. Right hemispheric over-activity in vertebrates is associated with wariness and depression (the subject as prey). Left hemisphere circuitry develops later, and processes in a linear rather than gestalt fashion, organized around language, logic and abstractions. At the affective level, left hemisphere is more curious, exploratory, danger-denying, even hypomanic (the subject as predator).

Petchkovsky and colleagues gave the following explanations for why the bilateral activation and subsequent shift to right hemispheric dominance occurs:

… the pattern of symmetrical activation suggests that the hemispheres are talking with each other, at least initially, and we surmise that the word-processing left hemisphere ‘conveys its concerns’ to the right hemisphere very early on in the piece.

They also theorized:

The right hemisphere probably carries more of the fearful response …. But within 3 to 5 seconds, the left hemisphere has ‘won’ the dialogue ….

Petchkovsky and colleagues believe their results also support the “Resonance Circuity” proposed by Dan Siegel, which has been associated with self and other awareness, mindfulness, and empathy. Petchkovsky and colleagues believe the resonance circuity is activated internally during complexes much the way it is activated interrelationally. They wrote:

While Siegel and his colleagues talk of the ‘resonance circuits’ primarily in the context of the relationship between the individual and his significant others, in the complexed response the process is a highly internalized one. What is being accessed is some representation of the ‘internal other’ which seems in conflict with the self.

The results of the fMRI brain scans are very strong, although the sample size was small (12 subjects). Of note, there has been much criticism of making bold claims about human nature based on brain scan studies, especially when the number of subjects in the study are relatively low. (Some writings on the topic are written by Raymond TallisJay Van Bavel & Dominic Packer, and Sally Satel & Scott Lilienfeld.) I think the value of this particular article and study is the researchers attempt to test Jung’s theory with modern technologies as well as connect his ideas to researches in neuroscience and human development not available when Jung first penned his theory of complexes.

As of October 10, 2013 the full article was available for free downloaded at The Journal of Analytical Psychology.


Petchkovsky, Leon, Michael Petchkovsky, Philip Morris, Paul Dickson, Danielle Montgomery, Jonathan Dwyer, and Patrick Burnett. “fMRI responses to Jung’s Word Association Test: implications for theory, treatment and research.” The Journal of Analytical Psychology, 2013, 58 (3), 409-431.

References (both quoted in Petchkovsky et al.):

CG Jung (1921). ‘Psychological Types.’ Collected Works, Volume 6.

CG Jung (1934). ‘A review of the complex theory.’ Collected Works, Volume 8.

By Laura K. Kerr, PhD
SJS Contributor

The post Brain Scans Used To Replicate Jung’s Word Association Test was written by  and was syndicated with the authors permission. Visit her website at Laura K Kerr, PhD.

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