Miguel Aguilera   complex systems, neuroscience and cognition

Critical integration in neural and cognitive systems: Beyond power-law scaling as the hallmark of soft assembly

I just published a new paper with Ezequiel Di Paolo in Neuroscience & Biobehavioral Reviews. Here we review the link of self-organized criticality and integrated information with ideas about soft assembly in neural and cognitive process. Studying the properties of power-law scaling processes as a in indicator of properties like soft-assembly, self-organization or interaction-dominant-dynamics is a suggestive approach for the understanding of cognitive process from a complex systems perspective. However, critics have suggested that these approaches operate mostly at the level of analogy or metaphor between real phenomena and idealized toy models. We suggest that this issue can be resolved by exploring what specific kinds of criticality we should expect from cognitive agents, and exploring a particular type of criticality related with integrated information theory, as a a system’s susceptibility to changes in its own integration (Aguilera & Di Paolo, 2019). We find that identifying this critical integration is more informative than power-law measures about the underlying processes of a system (e.g. agent-environment asymmetries, robust of sensorimotor interaction).

Aguilera, M & Di Paolo, EA (2021). Critical integration in neural and cognitive systems: Beyond power-law scaling as the hallmark of soft assembly. Neuroscience & Biobehavioral Reviews 123; https://doi.org/10.1016/j.neubiorev.2021.01.009


Inspired by models of self-organized criticality, a family of measures quantifies long-range correlations in neural and behavioral activity in the form of self-similar (e.g., power-law scaled) patterns across a range of scales. Long-range correlations are often taken as evidence that a system is near a critical transition, suggesting interaction-dominant, softly assembled relations between its parts. Psychologists and neuroscientists frequently use power-law scaling as evidence of critical regimes and soft assembly in neural and cognitive activity. Critics, however, argue that this methodology operates at most at the level of an analogy between cognitive and other natural phenomena. This is because power-laws do not provide information about a particular system’s organization or what makes it specifically cognitive. We respond to this criticism using recent work in Integrated Information Theory. We propose a more principled understanding of criticality as a system’s susceptibility to changes in its own integration, a property cognitive agents are expected to manifest. We contrast critical integration with power-law measures and find the former more informative about the underlying processes.