Oryan Zacks (Tel Aviv University, Israel): Evolutionary analyses of human-centred theories of consciousness

The field of consciousness studies has gained significant momentum in recent decades, with multiple theories attempting to relate subjective experience to specific neural structures and cognitive processes. Most theories are exclusively concerned with human consciousness, paying minimal attention to evolutionary considerations. When an evolutionary perspective is applied, it is usually limited to the hominin or primate lineages. The study of animal minds places human consciousness in a broader context, providing better understanding of aspects of the mind shared across many species, as well as aspects unique to humans. An evolutionary analysis is especially critical if we suspect that consciousness itself predates the emergence of primates, allowing us to probe its origins, and examine later elaborations. 

In this talk I will demonstrate the potential of an evolutionary analysis by focusing on a single theory, the Global Neuronal Workspace Theory (GNWT) of consciousness. A leading theory in the field, GNWT posits an intimate relationship between consciousness and cognition, and offers many testable predictions. However, the theory also has explanatory limitations and has recently been criticized after several of its predictions failed in an experimental setting. My analysis will focus on basal fish which most resemble the common ancestor of all jawed vertebrates.  

The analysis reveals that the major components of the GNWT architecture can be identified in basal vertebrates, indicating that they comply with the theory’s requirements and should be considered minimally conscious. Surprisingly, the best candidate for the primary hub of the global workspace in basal fish is the hippocampal homologue, which also plays an important role in memory formation and storage. This finding has implications for the conceptualization of memory and consciousness and the evolutionary relationship between them. It suggests that the functional separation between the hippocampus and neocortex, as found in the mammalian brain, is unnecessary for supporting minimal consciousness. More broadly, this analysis strengthens the idea that consciousness developed early in evolution, all vertebrates should be considered conscious, and the neural architecture needed to support minimal consciousness is simple relative to the human brain.  

To conclude, conducting an evolutionary analysis of a human-centered theory of consciousness can both broaden the scope of the theory but also challenge it. In this instance, the GNWT was found to serve as a useful framework for considering many kinds of conscious beings, as the analysis could easily be extended beyond vertebrates. This can be viewed as a strength of the theory and a demonstration of its value. However, some amendments are needed to enable better generalization. More broadly, applying insights from the field of animal minds may contribute to efforts to compare or reconcile currently competing theories of consciousness. The route to understanding the nature of consciousness necessarily passes through the study of the diverse instances of conscious beings alive today.