Editing Animal cognition (section)

==== Perceptual categories ====
Perceptual categorization is said to occur when a person or animal responds in a similar way to a range of stimuli that share common features.  For example, a squirrel climbs a tree when it sees Rex, Shep, or Trixie, which suggests that it categorizes all three as something to avoid.  This sorting of instances into groups is crucial to survival.  Among other things, an animal must categorize if it is to apply learning about one object (e.g. Rex bit me) to new instances of that category (dogs may bite).<ref name="Shettleworth" /><ref name="Wass" /><ref name="Zentall" />