Analogical reasoning involves recognizing that two situations share a common relational structure despite differences in surface features, and using knowledge about one to reason about the other. When Rutherford compared the atom to the solar system, he transferred the relational structure (small bodies orbiting a central mass) from a familiar domain (astronomy) to an unfamiliar one (atomic physics). Analogy is considered central to creative thinking, scientific discovery, and everyday problem solving.
Structure Mapping Theory
Dedre Gentner's structure mapping theory (1983) proposes that analogy involves mapping relational structures (not individual features) from a source to a target domain. The mapping is guided by systematicity — preference for connected systems of relations over isolated matches. "The atom is like the solar system" maps the causal relational structure (gravitational attraction → orbiting), not surface features (the sun is hot, but the nucleus is not).
Spontaneous Analogy
A persistent finding is that people rarely notice useful analogies spontaneously. Gick and Holyoak (1980) found that participants who read a story about a military problem (converging forces) rarely applied the analogous solution to a medical problem (Duncker's radiation problem) without a hint to use the story. This suggests that while analogical reasoning is powerful when engaged, the retrieval of relevant analogies from memory is a bottleneck — people tend to retrieve sources based on surface similarity rather than structural correspondence.
Gentner's career of similarity hypothesis proposes that children initially rely on surface similarity and gradually develop the ability to reason about deeper relational structures. Young children can make analogies when surface and relational similarity align but struggle when they conflict. The ability to focus on relational structure and ignore surface features develops through childhood and adolescence, paralleling increases in working memory capacity and executive function.