English: Adaptation of Figure 4 on p.851 of Nuerk, Hans-Christoph, Wiebke Iversen, and Klaus Willmes (July 2004). "Notational modulation of the SNARC and the MARC (linguistic markedness of response codes) effect". The Quarterly Journal of Experimental Psychology A 57 (5): pp. 835-863. DOI:10.1080/02724980343000512. Retrieved on 2007-09-19. Although this image is patterned on their diagram, none of the original image was copied or included.

The diagram shows the output of a statistical analysis run on a computer, called a smallest space analysis. The input data are response times from an experiment in which subjects were shown numbers and asked to identify them as odd or even by pressing a button with their left or right hands. In the smallest space analysis, the axes are arbitrary; only the clustering of data is meaningful.

Conditions that are congruent with their linguistic markedness (even numbers responded to with the right hand, odd with the left hand) fall into a cluster on the right side of the diagram. Conditions that are incongruent (even with the left hand, odd with the right hand) fall into a cluster on the left side of the diagram. In both conditions, zero is separated from the other numbers; it appears at the top of the diagram.

The following caption from Nuerk, Iversen & Willmes (2004, p. 851) is modified with square brackets in order to fit the colored graphic: "SSA for positive ... Arabic numerals 0 to 8 responded to with the right hand [green and pink] and the left hand [blue and orange]. MARC-compatible conditions [green and blue] and MARC-incompatible conditions [pink and orange] are depicted differently. Again, parity, magnitude, and response hand did not lead to separate grouping of different conditions, but only MARC compatibility or incompatibility. It can also be seen that zero strongly differs from all other numbers regardless of whether it is responded to with the left or the right hand. (See the line that separates zero from the other numbers.)"