As an academic psychologist, Spellman's research was in memory and higher order cognition (analogical, inductive, and causal reasoning).
[3] As a legal academic, her work includes co-authoring "The Psychological Foundations of Evidence Law" with Michael J. Saks.
Spellman's work on analogy, mostly with her advisor Keith Holyoak,[9] is best known for the article: “If Saddam IS Hitler then Who is George Bush?” (JPSP, 1991).
[10] It uses real life current events (the first Persian Gulf War) to examine the importance of knowledge and flexibility in analogical mapping.
“Crediting Causality” (1997, JEP:G), based on her dissertation, formed the groundwork for later papers with implications for views of legal causation.
[12][13] Her work on multi-event causation illustrated limitations on reasoning about the independent effects of two causes on one outcome (as might be seen in Simpson's paradox[14]).
[22] Her final editorial, “A Short (Personal) Future History of Revolution 2.0”[23] has been cited frequently as an introduction to the reform movement.