Could human decision making have evolved from food finding? One of the things human's do (and possibly other animals) is consider various options, imagine what they would be like, and then make a choice. This is called a "tree search". For example, "should I take the job offer A or B"?

Now, I wonder if this abstract decision making, may have evolved from food finding. And what is the smallest animal that does this sort of thing?

For example, imagine a small monkey or squirrel climbing a tree. When it gets to a branch it has a choice of taking the left branch or the right branch. It has to guess which branch is likely to lead to the best crop of fruit.

Once it has got fruit from one branch it may have to retrace its steps to get to the next branch. 

So I would suggest that this sort of "tree search" would probably have evolved in mammals brain before humans repurposed these brain pathways to do more abstract decision making involving language.

I am trying to think of other animals that this would apply to. For example a rabbit may have a choice between branching tunnels.

A bear might have a choice of paths up a mountain and so on. 

Rats are good maze finder so they must have this ability to make choices.

I wonder what other animals do this sort of thing? Rather than making a choice at random? It would have to be an animal at least as advanced enough to have a memory.
C. elegans is the simplest model organism whose nervous system has been studied extensively. C. elegans certainly makes decisions; I would feel pretty confident in saying that decision making is an ubiquitous feature in the nervous system of freely moving animals.

It is also non-controversial to consider more complex behaviors as having evolved from more simple ones (finding food/evading predation/mating). You can even reduce a lot of complex behaviors directly to those simple ones, and certainly neural mechanisms for grouping and distinguishing between different patterns (an essential component of language but also many other behaviors) are conserved across domains.

However, it is not correct to refer to all decision making as a tree search: a tree search is a particular family of algorithms and not what you describe. Even tree-like problems need not be solved with a tree search. Specifically, tree search is a computational algorithm that works well in the serial processing environment of computer science. Analogies between brains and computers often break down at the level of algorithms, because brains are massively parallel. That doesn't mean tree search-like algorithms are absent from the brain, but you should not take such a narrow view a priori.



Christiansen, M. H., &amp; Kirby, S. (2003). Language evolution: Consensus and controversies. Trends in cognitive sciences, 7(7), 300-307.

Faumont, S., Lindsay, T. H., &amp; Lockery, S. R. (2012). Neuronal microcircuits for decision making in C. elegans. Current opinion in neurobiology, 22(4), 580-591.

Fitch, W. T. (2005). The evolution of language: a comparative review. Biology and philosophy, 20(2-3), 193-203.