Skip to main content

Relations (Commensalism, Symbiosis, Parasitism)


In his book Attention and Interpretation (1970), Wilfred R. Bion conducted a parallel study of the relations between the mystic and the group, between the container and the contained, and between a new idea and the psychism in which it appears. He used the same relations model to describe these three situations with three types of relations: commensal, symbiotic, and parasitic.

Bion uses the relation of the mystic to the group as a springboard for his developments. The mystic, whom he also calls the genius or messiah, is the individual who brings new ideas to the group. He is opposed to the establishment, whose role is to maintain the cohesion and stability of the group. The mystic and the establishment need each other. By maintaining the stability of the group, the establishment enables the advent of the mystic who is engendered by the group to which the mystic gives life (psychic, spiritual, or scientific); the mystic needs the group, therefore the establishment, in order to introduce new ideas to the greatest number of people, for example the benefits of Newton's physics or Freud's psychoanalysis.

But together the group and the mystic maintain relations which, although they include a charge of creativity, also imply a charge of destructiveness. The new idea introduced by the mystic always threatens the existence of the group or one of its sub-groups.

These are the definitions that Bion gives of the three types of relations he describes: "By 'commensal' I mean a relationship in which two objects share a third to the advantage of all three. By 'symbiotic' I understand a relationship in which one depends on another to mutual advantage. By 'parasitic' I mean to represent a relationship in which one depends on another to produce a third, which is destructive of all three" (p. 95).

In the commensal relation there is coexistence on each side of the relation in such a way that each is inoffensive to the other. In the symbiotic relation "there is a confrontation and the result is growth-producing" (p. 78). In the parasitic relation the product of the association destroys the two associated parties; it is a relation that is marked by envy that "cannot be satisfactorily ascribed to one or other party; in fact it is a function of the relationship" (p. 78).

Bion gives different examples of these three types of relations, sometimes drawn from the relations of the mystic and the group, sometimes from the relations of the contained, noted , to the container, noted : "The container," he writes, "is represented by a mouth or a vagina, the contained by a breast or a penis" (p. 95). He illustrates the parasitic, symbiotic, and commensal relations with the example of a man who wants to communicate his annoyance but who is submerged by the emotion and who begins to stutter and becomes incoherent: "Such a failure is the outcome of a 'parasitic' relationship between the contained (or rather, not contained) material and the speech devised to contain it: 'container' and 'contained' have produced a third 'object'incoherencewhich makes expression and the means of expression impossible. In so far as the imaginary episode led to a development of powers of expression and of the personality that strove to express itself, the relationship could be described as symbiotic. 'Commensal' is illustrated by supposing that the episode occurred in an age and society (as in Elizabethan England) in which language had reached a point of development where the ordinary man was inspired to speak it well: that which was to be expressed and the vehicle for its expression profited from the culture to which they belonged" (p. 96).

Didier Houzel

See also: Bion, Wilfred Ruprecht; Symbiosis/symbiotic relation.


Bion, Wilfred. R. (1970). Attention and interpretation. London: Tavistock Publications.

Grinberg, León, et al. (1991). New introduction to the work of Bion. Northvale, NJ, and London: Jason Aronson.

Symington, Joan, and Symington, Neville. (1996). The clinical thinking of Wilfred Bion. London: Routledge.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Relations (Commensalism, Symbiosis, Parasitism)." International Dictionary of Psychoanalysis. . 7 Feb. 2019 <>.

"Relations (Commensalism, Symbiosis, Parasitism)." International Dictionary of Psychoanalysis. . (February 7, 2019).

"Relations (Commensalism, Symbiosis, Parasitism)." International Dictionary of Psychoanalysis. . Retrieved February 07, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.