Full Idea
All organisms form categories: even mealworms have category-based preferences, and higher-order animals such as pigeons or octopi can display quite sophisticated categorical judgements.
Gist of Idea
Even fairly simple animals make judgements based on categories
Source
Susan A. Gelman (The Essential Child [2003], 01 'Prelims')
Book Reference
Gelman,Susan A.: 'The Essential Child' [OUP 2005], p.11
A Reaction
[She cites some 1980 research to support this] This comes as no surprise, as I take categorisation as almost definitive of what a mind is. My surmise is that some sort of 'labelling' system is at the heart of it (like Googlemail labels!).