When we count objects, counting is relatively fast with small sets, i.e. less than four objects. This fast enumeration of objects is called subitizing. Several theories were proposed to explain this phenomenon. In this work we propose that the arrangement of objects is critical in the speed of enumeration of objects, and there is only one model that can account for this feature: the pattern recognition theory. According to this theory, if we can see only a few objects they can be perceived as a pattern (yeah, sounds simple), and recognizing the pattern is enough to recall the appropriate number, e.g. triangle is three, or square is four, etc.

In this specific work participants enumerated objects. The objects were arranged either in a symmetrical and well known configurations (the so called canonical patterns) or in a random pattern. Additionally, we used two further arrangements: slightly and strongly distorted canonical patterns. Participants could subitize sets with more than four objects if they were arranged canonically. Furthermore, the more noisy the patterns were, the less likely the participants could subitize them. These results are consistent with the ideas that (1) subitizing is pattern recognition, and (2) the pattern recognition system is flexible enough to transfer any pattern of less than five objects to a known pattern, but beyond four this ability is limited.

We gave further theoretical considerations in our paper:

Krajcsi, A., Szabó, E., & Mórocz, I. Á. (2013). Subitizing Is Sensitive to the Arrangement of Objects. Experimental Psychology, 60(4), 227–234.

See a short slideshow about some of the ideas. Note that the graphs do not necessarily show the final published data.

Description of the project in Hungarian.