What is the physiological explanation for 'intelligence'?

Question

I used to study the process of cephalization in different species from various phylas. There was also a unit I covered over the anatomy of the brain and its various roles in coordinating the endocrine and nervous systems. The only difference between humans and the rest of the animals is our rather superior intelligence.

What constitutes this intelligence? There are animals with obviously larger brains than ours but they lack the cognitive faculty. How was it possible for humans to develop intelligence so quickly?

What is the physiological explanation as to how a brain can exhibit 'intelligence' (if its even possible to define it)?

(An explanation on the molecular and systematic level would be appreciated)

Answer 1

There are at least four principal features needed for intelligence: (1) large number of neural pathways; (2) distinct layers or regions for neural processing; (3) a high degree of interconnectedness among neural paths; and (4) a mechanism for controlling or initiating thoughts.

The first three features have been observed through dissection, direct observation, and by imaging that shows levels of neural activity. 'Intelligent' species have these three physical characteristics, while less intelligent species generally do not. In addition, artificial neural networks arranged in this fashion have astounding 'reasoning' ability and capacity to learn, demonstrating that this physical arrangement actually works.

Even though artificial neural networks show characteristics of learning and reasoning, the precise mechanisms for storing information and allowing a person to control the thought process are not known. There are theories and evidence that the neural connections rearrange--similar to the way artificial neural networks function. But a rearrangement of connections can only account for memory and association, and not for controlling or initiating thoughts. The though process itself is pretty much a mystery.

Answer 2

Mostly it's a difference in degree rather than kind. When we know what to look for, we find intelligent behavior in dolphins, whales, other primates, and several other animals. The size of the brain is related to the total duties it needs to perform, including the mechanical as well as the cognitive.

Major credit is given to the hand with the opposing thumb. Animals without that can have grand thoughts but can't put them into action. Similarly, bipedal walking frees the hands for doing useful things. I think we would learn an incredible amount if we found a way for dolphins to communicate with us. More, if we could give them prosthetic hands and then see what they could learn to do. I think it would be humbling. I think a bigger difference between man and other animals is the spirit, but that's well beyond the realm of science.

Answer 3

Intelligence is the capacity to think and reason clearly and to act purposefully and effectively in adapting to the environment and pursuing one's goal.