ABSTRACT
The stimuli are usually simple, uniform, and punctate. This is a reasonable and productive experimental strategy. Specific stimulus dimensions can be isolated for detailed study, such as spectral value, tonal frequency, and line orientation. Simple stimuli do not represent the real world, but many other scientific preparations are also abstracted from the real world, including pure chemicals, smooth surfaces, genetically identical organisms, and single neural units. Instances of naturalistic environments and conceptual categories do not lend themselves readily to the dimensional analysis that is characteristic of the study of stimulus control. Simple elements may be more useful for the study of emergent properties of arrays of elements. The total numbers of elements in a pattern and their spacing differ between experiments. With larger numbers of stimulus elements, their relative numerosity is a salient characteristic. This dimension can be abstracted from complex arrays without the identification of specific numbers.
