Disclaimer: Given that I have not yet settled on a research direction, I here present one possible line of work I am actively considering.
It has been proposed that the control of fire (primarily, but not exclusively, via its effects on food processing) has been a defining element in shaping several of our species’ physiological adaptations (e.g., reduced gut volume, increased encephalization proportional to body size…), as well as cognitive (Wrangham & Carmody, 2010). I partly disagree with this view, both on theoretical and empirical grounds. More specifically, I would argue that the control of fire itself is the result of a cognitive explosion, which occurred as a function of a drastic dietary shift from (mostly) herbivores (such as our genetically closest relatives) to opportunistic scavengers (and then full-fledged hunters). This transition has clear cognitive implications. How did our species become an apex predator while lacking any aspect of physical prowess ubiquitous in the ever-present evolutionary prey-predator arms-races (a notion supported by evidence from molecular biology to evolutionary anthropology)? Our hominin line specialised in cognitive weaponry. One aspect of this cognitive arsenal is our understanding of causal forces, which is reflected in hunting technology (Gardenfors & Lombard, 2018).
Therefore, my currently ill-defined and general working hypothesis is that our enriched causal understanding (e.g. force dynamics) was selected for as a function of a biological commitment to a state of ketosis (from our scavenging transition, and which humans seem to be unique in), and interlocking with hunting technology and strategies. Such a notion is grounded in the broader Massive Modularity Framework, but also connects to Natural Pedagogy (Csibra & Gergely, 2009; e.g., crafting hunting technologies pose an opaque context to overcome), notions of metarepresentation modules (e.g., selective advantage of group-hunting cooperating strategies) and the adoption of an Intentional Stance towards both prey and allies (Dennett, 1995).
References:
Wrangham, R. W., & Carmody, R. N. (2010). Human adaptation to the control of fire. Evolutionary Anthropology.
Csibra, G., & Gergely, G. (2009). Natural pedagogy. Trends in cognitive sciences, 13(4), 148-153.
Gärdenfors, P., & Lombard, M. (2018). Causal cognition, force dynamics and early hunting technologies. Frontiers in Psychology, 9, 87.
Dennett, D. C. (1995). Darwin's dangerous idea: evolution and the meanings of life. New York, Simon & Schuster.