An ACT-R model of syllogistic inference

We describe SYLLOG, a model of syllogistic inference, built within the ACT-R framework. Its construction was guided by data obtained from 88 subjects performing the syllogistic inference task, The model's inference engine uses the PC inference rule Hypothetical Syllogism (HS) and a set of modal logic transformation rules either to create a representation of the premises that allows an appropriate use of HS, or to check the appropriateness of having already used HS to obtain a putative conclusion.