Psychology could legitimately be considered a subset of economics.
The counterargument to the proposition in my earlier post would be to show that there is economic activity which relies on nonhuman behaviours. Automated financial trading or AI-based management systems (financial, corporate, industrial, governmental, etc.) might be possible exceptions, which raises further interesting questions.
Though there is certainly daylight: my subfields of Industrial Organization and Computational eocnomics are way more related to quantitative finance, ML, and similar than voting behavior.
The thrust of my pithy question was whether or not the principle subjects of economics --- of human production, consumption, and exchange --- where the sum total of all psychological inquiry.
I suspect not.
The relevant questions are:
1. Which field of study encompasses more elements, economics or psychology?
2. Are these fields intersecting, and if so, is one a proper subset of the other or not?
In a Venn diagram sense, how do the sets relate?
Psychology includes numerous branches, fields, divisions, and foci, of which choice determination is only a very small element. See for example:
<https://www.simplypsychology.org/branches-of-psychology.html>
<https://en.wikipedia.org/wiki/Psychology#Major_schools_of_th...> (specifically schools of thought).
Contrast branches of economics. Numerous, but ... somewhat less expansive as compared with psychology:
<https://en.wikipedia.org/wiki/Outline_of_economics#Branches_...>
Note that psychology, economics, sociology, political science, and anthropology all emerged out of what had previously been moral philsophy largely during the 19th century. Divisions and focus are somewhat arbitrary and strongly influenced by institutions and other pressures --- in the case of economics, political policy influences are notoriously strong, though other disciplines aren't immune from same. But if I had to matryoshka the two, I'd nest econ within psych.