Liquid brains, solid brains

Ricard Solé, Melanie Moses, Stephanie Forrest

Research output: Contribution to journalReview articlepeer-review

41 Scopus citations


Cognitive networks have evolved a broad range of solutions to the problem of gathering, storing and responding to information. Some of these networks are describable as static sets of neurons linked in an adaptive web of connections. These are 'solid' networks, with a well-defined and physically persistent architecture. Other systems are formed by sets of agents that exchange, store and process information but without persistent connections or move relative to each other in physical space. We refer to these networks that lack stable connections and static elements as 'liquid' brains, a category that includes ant and termite colonies, immune systems and some microbiomes and slime moulds. What are the key differences between solid and liquid brains, particularly in their cognitive potential, ability to solve particular problems and environments, and information-processing strategies? To answer this question requires a new, integrative framework. This article is part of the theme issue 'Liquid brains, solid brains: How distributed cognitive architectures process information'.

Original languageEnglish (US)
Article number20190040
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Issue number1774
StatePublished - 2019
Externally publishedYes


  • Ants
  • Cognition
  • Evolution
  • Immunology
  • Neurons
  • Swarms

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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