If the question is what distinguishes humans from all other species, then I think I found a snippet from my computer programming and the analogy of human thinking to artificial neural networks.
As we as computer programmers increase the number of input & hidden nodes in those two layers, in artificial neural networks, it reaches the point that it becomes unstable & there appears to be no good solutions & or stupid answers. Noting the difference between massive parallel processing of humans/animals and simple PCS recalculating in loops one at a time, it turns out that neural networks do not scale up so easily. Maybe it is just my crappy VB6 code I cut & paste.
This would explain why large animals such as whales & elephants do not have same mental capacities as humans. I conjecture that humans some how solved the problem of scalability in neural networks to such an extent it made us humans have much better analytical & conceptual ability to animals. This may not be biological but maybe more cultural as when humans learn a language. Our brain is wired up 2/3 before we are born & last 1/3 up to age of 15 or so.
This is a wild conjecture & really is nothing to do with evolution. I guess....
If language turns out to be genetic then maybe I am wrong.
Conclusion in process of adding more nerve cells to brain it turns out animals missed out on solving problem of scalability of neural networks. Humans solved the problem and a whole range of symbolic thinking in our associations between what we remember & what we observe eventuated.
