The size of brain We tend to think the size of the brain correlates with the extent of intelligence. However, that’s not necessarily true. Actually, many possible complex changes in the brain have quite different functional consequences. Both hierarchic-recursive logic of sentence structure and the distributed multilevel associative relationships are essentially unlearnable by an aggressive information-process approach. This is because nonhuman species’ intrinsic learning biases undermine the process before it can even get started. It is said that these biases are produced naturally by means of the size of the brain. The species that have the large brain do better intergenerational information transfers of learned information from parent to offspring by focusing on effort on just a few malleable offspring. On the other hand, the species the small brain do better to sample alternative adaptational strategies by producing large number of offspring with different variants of preprogrammed behavior patterns and leaving the rest to natural selection. The difference of the brain size leads to the difference of how to transfer information learned. It may help explain why nonhuman species cannot use languages. This is because smaller-brain species have the biases against appropriate learning strategies and large-brain spices can evolve symbolic communications.