People find difficulty in performing syllogistic reasoning. This paper outlines some reasons for poor syllogistic reasoning. Representational systems (RS) used in presenting and evaluating syllogisms can be distinguished in terms of attributes such as specificity, expressiveness, and abstraction. Graphical RSs have pedagogical potential because of their expressivity and specificity attributes. The paper looks at four different graphical RSs for supporting syllogistic reasoning: Venn diagrams, Euler circles, Stennings Euler circles, and Tarski's World (TW). Each is described in terms of those distinguishing attributes. Claims are made about which should generate better learning outcomes as a result of different degrees of these attributes. Empirical work is underway which involves the construction of tasks which help learners to see the relationship between a diagram and the syllogism. The study will involve the pre- and post-testing of 18-year old school pupils on premises and conclusions from 10 selected prototypical syllogisms with non-linguistically biased predicates. Four figures illustrate the representational systems. (Contains 16 references.) (Author/MAS)