Simultaneous perception, also known as Subitizing, describes the ability of the human brain to immediately grasp the number of objects without having to actively count them. This process takes place automatically and takes less than 250 milliseconds.

Typically, this is possible with about four to six objects – the maximum number depends heavily on the arrangement. Under optimal conditions and if our perception is able to identify simple subsets through a process known as chunking (e.g. three equal groups), the number of a group of 9 elements can also be determined without counting. For larger quantities, counting is required, which takes up cognitive resources and takes longer.

 

This image impressively demonstrates the effect of design on the perception process.

Most people immediately recognize that there are 9 objects in the right-hand arrangement. They do not have to count them. In the left-hand arrangement, there are only 8 objects. However, most people have to "count" here. This example impressively demonstrates the effect of "design" on the perception process.

 

Origin

This cognitive ability was examined in experiments by Kaufman et al. (1949) and Trick & Pylyshyn (1994), which showed that people can immediately recognize small amounts of visual elements without having to count them individually.

  • Kaufman, E. L., Lord, M. W., Reese, T. W., & Volkmann, J. (1949). The Discrimination of Visual Number. *The American Journal of Psychology*, 62(4), 498–525.
  • Trick, L. M., & Pylyshyn, Z. W. (1994). Why are small and large numbers enumerated differently? A limited-capacity preattentive stage in vision. *Psychological Review*, 101(1), 80–102.

Application in UX and UI design

Simultaneous perception is particularly relevant in UX and UI design because users absorb visual information more quickly when the number of elements is limited. Designers should arrange important elements into groups of four to six objects, as these quantities can be quickly grasped without conscious counting (see also: The Magical Number Seven). This reduces cognitive load and allows users to immediately focus on relevant information.

The targeted use of clear, concise structures or chunking can significantly increase the number (see figure above). The example also shows how much order and structure support cognitive information processing. Alignment, rhythm and white space (spacing) play an important role here.

At this point, we would therefore also like to refer you to the Gestalt Psychology, which describe the most important principles of perception.

Impact on the User Experience

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Further information