Dissertations, Theses, and Capstone Projects

Date of Degree


Document Type


Degree Name





Eric Mandelbaum

Committee Members

Katherine Ritchie

Elisabeth Camp

Stephen Neale

Michael Devitt

Subject Categories

Comparative Psychology | Philosophy of Mind | Philosophy of Science


Language of Thought Hypothesis, Cognitive Science, Philosophy of Mind, Comparative Psychology, Mental Representation, Non-Human Animals


What might we learn if we take seriously the possibility of non-human Languages of Thought (LoT)? A LoT is a combinatorial set of mental representations. And, since mental representations and rules of combination vary in kind, there are many possible LoTs. Simple LoTs might lack familiar features of the putative human LoT, such as object representations, recursively defined rules of combination, sentential connectives, or predicate-argument structure. The most familiar arguments for the existence of LoTs, such as those from productivity, systematicity, concept learning, and perceptual computation, all fail when applied to non-human animals. But recent empirical evidence motivates attributing LoTs to at least some non-human animals. First, observational and experimental data suggest paper wasps and some bee species—but, as far as we can see, not fruit flies—form preference orderings for sugar sources and noxious stimuli. Moreover, at least one arthropod, the honeybee, is capable of cardinally ordering natural numbers, including zero. These results are difficult to explain with associative learning models, even ones that incorporate concepts, magnitudes, or object files. However, they are readily explained by transformations over representations in a LoT. And second, results from a recently developed experimental paradigm suggest chimpanzees, olive baboons, and an African grey parrot are competent with disjunctive syllogism. The best explanation of this competence posits combinations of connective-like mental representations, which function to combine syntactically with other representations. These results bolster the explanatory purchase of non-human LoTs, and of LoTs as a psychological kind. They suggest continuity in the psychological competences of humans and other species.