Classification, within the ACLs, is the organization of material objects and actions into groups. The simplest groups are formed in ACL 3.6 by sorting material objects that are alike, one criterion at a time. Striking colors, elementary shapes and easily seen differences in size are the features that capture their attention.
The concept of all of the objects or all of the space captures their attention within ACL 3.8. Classification is still closely connected to the perceivable features of the material objects that are in front of them.