Psychology of Consciousness: Theory, Research, and Practice, Vol 12(4), Dec 2025, 479-490; doi:10.1037/cns0000402
Klein et al. (2023) argued that the evolutionary transition from respondent to agent during the Cambrian explosion would be a promising vantage point from which to gain insight into the evolution of organic sentience. They focused on how increased competition for resources—in consequence of the proliferation of new, neurally sophisticated life-forms—made awareness of the external world (in the service of agentic acts) an adaptive priority. The explanatory scope of Klein et al. (2023) was limited to consideration of the conscious apprehension of externally sourced content—that is, content delivered from the sensory registration of objects occupying phenomenal space. But consciousness—at least for humans—takes its objects from internal as well as external sources. In the present article, we extend their analysis to the question of how internally sourced content (i.e., mental states) became the object of conscious apprehension. (PsycInfo Database Record (c) 2025 APA, all rights reserved)