Perception & Cognition
Gestalt Principles of Perceptual Grouping
(Summary 1998, J.S.Longstaff) [1]

Certain principles were identified by the Gestalt psychologists which describe how separate stimuli (visual images, sounds, physical sensations) tend to be organised into groupings during perception and memory. This spontaneous organisation of stimulations is believed to reflect basic processes in the brain [2]. Grouping separate items together can highlight a counterpoint or symmetry between them. Some of the principles of grouping have obvious similarities with other methods of counterpoint and relationships.

Gestalt psychologists referred to the fundamental organisational factor as the law of “pragnanz” [3], literally translated from German as “concise”, “terse”, “neatly brief” and “expressing much in few words” [4]. In the language of the Gestalt psychologists, the law of pragnanz means that stimulations will tend to be organised during perception into groupings which are the most “good”, “regular”, “simple”, “stable”, “logically demanded”, with “inner coherence”, “inner necessity”, “wholeness”, and that within each element exists the principle of the whole group of elements.

It is hypothesised that perceptual processes will always organise the stimuli to be as “good” (according to pragnanz) as the conditions will allow, or that “any stimulus pattern tends to be seen in such a way that the resulting structure is as simple as the given conditions permit” [5]. “Several specific manifestations of pragnanz are distinguished [6]:
“similarity”
(or “equality”) 		when stimuli have a similar shape, colour, orientation etc. as each other they tend to be grouped together relative to other more dissimilar stimuli.
“proximity” when stimuli are near to each other in time or space they tend to be grouped together relative to more distant stimuli.
“common fate” stimuli which are moving at the same time, in the same direction, or travelling the same distance, tend to be grouped together.
“continuation”
(or “direction”) 		a continual series of stimuli (eg. a row or a column of separate objects) will tend to be grouped together as a single unit. The continuation of a straight line maintains its direction and the continuation of a curved line maintains its curvature.
“closure” if a collection of stimuli completes, or nearly completes, a circuit which encloses space, this entire area will tend to be grouped together as a single enclosed unit. The principal of continuation is operating within closure.
“unum and duo” a stimuli configuration will be perceived as one figure, or perceptually divided into two or more sub-figures, depending on which of these groupings arranges the stimuli into figures which exhibit the greatest amount of simplicity and symmetry

In many cases the principles of organisation all work together in agreement to derive a particular grouping of the stimuli (eg. 2 people in proximity with unison movement - perceptually grouped as ‘together’ [7]). In other situations the principles may be in conflict and so, eg. an organisation according to proximity (eg. people nearby to each other) might dominate a different organisation which would have occurred according to similarity (people dressed the same).

The psychological causes of pragnanz can be considered within the Nature vs. Nurture debate:
Gestalt laws of perceptual organisation make reasonable intuitive sense, but they are obviously descriptive statements possessing little or no explanatory power. The Gastaltists appear to have believed that their laws reflected basic organisational processes within the brain [Nature], but it is much more plausible to assume that the laws arise as a result of experience [Nurture]. It tends to be the case that visual elements which are close together, similar, and so on, belong to the same object, and presumably this is something which we learn.” (Eysenck & Keane, 1990, p. 58).

According to Gestalt perceptual grouping, perceptual and cognitive processes attempt to group stimuli and information into the simplest, most concise, most symmetrical manner possible. This provides a great deal of cognitive economy and so is a beneficial strategy for an organism, even at the risk of remembering events as more concise or simplified than they actually are.

NOTES
  1. This summary edited from Longstaff (1996, sec. IVA.30, IVB.27, Appendix XV.14-.15).
  2. For a psychological consideration of Gestalt organisations, see Eysenck & Keane (1990, p. 58).
  3. Pragnanz (Koffka, 1935, pp. 108-145; Wertheimer, 1923, pp. 79–83)
  4. Collins Dictionary
  5. Arnheim (1974, p. 53)
  6. Grouping principles are described by Koffka (1935, pp. 148-171) and Wertheimer (1923, pp. 75-87).
  7. Compare this to feelings of rapport and agreement during simultaneous and mirroring movement observed in NVC (Davis, 1982)

REFERENCES:

  • Arnheim, R. (1974). Art and Visual Perception; The New Version. (expanded and revised) Berkeley: University of California Press. (Originally published 1954).

  • Davis, M. (Ed.). (1982a). Interaction Rhythms. New York: Human Sciences Press

  • Koffka, K. (1935). Principles of Gestalt Psychology. London: Routledge and Kegan Paul. (4th printing 1955)

  • Longstaff, J. S. (1996). Cognitive structures of kinesthetic space; Reevaluating Rudolf Laban’s choreutics in the context of spatial cognition and motor control. Ph.D. Thesis. London: City University, Laban Centre. (for Gestalt, see sections  IVA.32e,.54,.111; IVB.27; APX XV)

  • Scott, N. (1998). A discussion of space and shape in the theatre of dance, and how we see a relationship between dance and its physical setting. MA Thesis, Laban Center, University of London.
    Documents the space of the three-dimensional stage with floor plans and direction signs used in the Constant Cross, referring to directions in General Space; theories of perceptual psychology (visual illusions or distortions) some described by Gestalt psychologists, were explored in practical performance experiments.

  • Von Frey, M. (1923). Variations in tactual impressions. Reprinted in A Source Book of Gestalt Psychology, (4th edition 1969) translated and edited by W. D. Ellis (pp. 193-195). London: Routledge and Kegan Paul.

  • Wertheimer, M. (1923). Laws of organization in perceptual forms. Reprinted in A Source Book of Gestalt Psychology, (4th edition 1969) translated and edited by W. D. Ellis (pp. 71-88). London: Routledge and Kegan Paul.