People's sensitivity to content vs. formal properties of visual stimuli: Evidence from category construction.

When people are asked to classify visual stimuli, they are often insensitive to formal properties, such as their 3D coherence or symmetry. We investigated whether this pattern of formal insensitivity would also be found using more familiar stimuli and properties: paintings that differ in their artistic style and words printed in two different typefaces. The experiments used the category formation paradigm in which subjects freely sort items into groups that seem most natural to them. They could sort each stimulus set up to three times. Only about half of the subjects in Experiment 1 ever sorted the paintings by artistic style, and only 12% did so on their first sort. Only 36% ever sorted by typeface, with many of the subjects stopping after two sorts and saying that no further categories were possible. Experiment 2 repeated the test of typeface using actual words cut out of newspapers and advertisements. Half the words were printed in boldface and half not. These items lacked any strong semantic connections, yet only 30% of subjects ever sorted the items into the bold and non-bold words. The results suggest that many people are not sensitive to the formal properties of stimuli that also have semantic content. Spontaneously noticing those differences may require a particular task with explicit instructions or experience in that domain (e.g., copyeditors or art students).