Gestalt theory
Gestalt is a general description for the psychological concepts that make unity and variety
possible in design. It is a German word that roughly translates as "whole" or "form." Gestalt
theory is involved with visual perception and the psychology of art among other things. It is
concerned with the relationship between the parts and the whole of a composition. Gestalt
principles build on the idea that people perceive information at the global level first and that,
depending on the presentation, the holistic view is made up of more than the individual
components.
The visual world is so complex that the mind has developed strategies for coping with the
confusion. Gestalt principles build a unified view of those strategies. When faced with visual
complexity and multiple options, the mind tries to find the simplest solution to a problem. One of
the ways it does this is to form groups of items that have certain characteristics in common.
When people look at a grouping of lines and circles, they do not look at each line and circle
individually; instead, they mentally structure them in some coherent, integrated way.
The basic Gestalt ideas and some examples follow.
Figure to ground
The image changes based on whether or not the light or dark area is seen
as the figure or the background. This leads to optical illusions such as the
face or vase.
In more practical examples, too tight kerning can introduce extra figures.
Here, it could be the two letters or an arrow, depending on what is seen as
the figure. In the word Bob, the first B is reversed out shifting the use of
black and white as figure or background.
Proximity
Grouping based on the relative placement of objects.
Because of the different space between the lines, the image appears to be
two double rows of dots. Likewise, the small circles or squares appear to
be grouped with the large circles or squares they are close to. However, in
neither case is anything in the image actually driving this view.
Proximity violation. A student said her mother saw this headline for a
concert ad and wanted to know who Elton Billy was. Most people know
the singer’s names and were able to essentially immediately parse them.
But normal reading is left to right, and so a reader not familiar with the
singers would expect the names to go across the page and not vertically.
ch 6 elton-billy.tif
Closure
Objects are completed to form the simplest possible figures.
The image consists of three circles with a triangle cut out, but because of
their relative placement, the eye also sees a triangle. Moving the circles to
a different place destroys the gestalt aspects of the image and turns them
into three random Pac-man characters.
Most people read the following text as ‘the cat,’ yet the symbol for ‘H’
and the ‘A’ are the same. The simplist interpretation is to see ‘the cat’ and,
thus, that is what people perceive.
Symmetry
Objects are grouped so they form symmetrical shapes around their center.
The image is seen as two overlapping squares since that is the simplest
interpretation, rather than as a small square and two squares with cutouts.
Similarity
Grouping objects that share visual characteristics or grouping by how
things look more alike than the other objects in the set.
The basic circle pattern is the same, but with similarity, the eye groups
these in rows of black and white circles or into groups of four objects
forming squares.
For control gauges, designing the system so the normal position is the
same on all of the gauges makes it easier to spot any deviation. Assume
only the third gauge in each row has an abnormal reading. In the first row,
each gauge would need to be examined individually, but the third gauge in
the second row breaks the pattern of the other three and is easily visible.
Continuance
Grouping by how people will follow a path seeking a conclusion or
resolution from clues that point in a particular direction.
The eye sees three lines going behind a dark area, since it is simpler to see
three rather than 6 separate objects. In the other image, the finger points to
the small ball and the eye is drawn to it, rather than to the larger ball.
Without the pointing finger, the eye would go to the large ball.
Gestalt ideas are important because people always impose structure on information regardless of
how unstructured it might be (Kwasnik, 1992; Witkin, 1978). It is up to the design team to
ensure the overall design matches the HII needs. Gestalt concepts help the design team to focus
on the overall presentation and not get too focused on the individual elements. Likewise, people
can identify website layouts with ‘greeked’ text (Tullis, 1993) purely based on the overall
appearance.
Wickens and Carswell (1995) developed the idea of the proximity compatibility principle (PCP),
which is similar to gestalt proximity concepts. PCP states that the perceptual characteristics of
the information should be designed so that its arrangement fits the cognitive demands of the task.
In other words, information which is used together should appear close together. If the task
requires two sets of information to be integrated, the system performs the integration and
displays the results. Conversely, information that is not used together should not appear together.
Notice how this principle helps the design team build good HII by pulling together information
relationships, relevance, and salience. Although this idea may appear self-evident, many systems
violate it, especially systems based around dumping information on the reader or systems
developed without a clear understanding of the HII requirements.