Islands in the Mind: Dynamic Subdivisions of Association Cortex and the Emergence of a Darwin Machine

Abstract

To model cognitive processing, language construction, and "intelligence" at a neurophysiological level using darwinian evolutionary mechanisms requires more than a survival-of-the-fittest principle. Darwinism is all about the copying success of patterns (typically DNA strings); here I outline a seconds-to-minutes competition between different spatiotemporal firing patterns in a multifunctional cortical workspace. The proposed mechanism for recall from a passive distributed memory into an active working memory is analogous to genotypes and phenotypes. The ephemeral working patterns copy themselves in the manner of wallpaper pattern repeats; they occupy flexible islands in the workspace (useful for multi-tasking and analogical reasoning) that compete with one another for the limited workspace, with a widespread pattern signaling object identification or readiness to act. Pattern evolution is accelerated by cortical equivalents of the roles played by climate change and lowered sea level in island biogeography. Chimeric islands containing a pastiche of patterns are judged against episodic memories in a way that bears some correspondence to the known organization of human language cortex.