Intelligence is all around us. Scientists are creating artificial intelligence that surpasses human expertise in games of strategy and skill. Even humble animals like bees may be far more intelligent than they appear. Intelligence may not even require a brain: non-neural systems and self-organizing swarms have joined the club of cognitive agents.

Paradoxically, this diversity makes it difficult to compare different kinds of intelligence. Any two intelligent things compare and contrast in a dazzling number of ways. The intelligence of each of Darwin’s “endless forms most beautiful” is exquisitely adapted to the environment in which it lives.

That appears to permit one of two explanations. Cognition might be simple learning, influenced by the environment and limited by brain size and body type. Or it might be an assemblage of bespoke modules, reshaped and renewed across lineages as needed. Both account for complexity, but neither gives us a meaningful way to compare intelligences across distant branches of the tree of life and AI.

In this project, researchers Andrew Barron, Marta Halina, and Colin Klein argue that there is a third way: the evolution of cognition is best explained by a handful of major transitions. They present five types of cognitive systems categorized by a type of information flow within them. Each transition consisted in changes to information flow in systems, opening up new capacities while transforming the scope of existing cognitive functions.

Researchers will explore the major transitions and their consequences. The project brings together cutting-edge work in comparative neurobiology, computational neuroscience, and philosophy. Much is speculative. But like all good speculation, it is grounded in specific, testable hypotheses.

This project aims to allow us to frame the relationship of human intelligence to other minds—what we have in common and where we might be unique. Exploring the major transitions in cognitive evolution will provide the principles that make possible a true science of comparative cognition.