Question:
Explain what is meant by relaxed selection and by masking, and outline how they may have collaborated to promote the evolution of human language capabilities.

Answer:
Relaxed selection is a "use or lose it" process by which certain traits are partially degraded or lost over multiple generations due to the fact that the trait no longer provides a benefit to the organism and hence is not subject to maintenance via natural selection. This can lead to the generation of new traits, as a new trait can emerge from the degraded one.

Masking is one form of relaxed selection where degradation of a trait is masked by the fact that the trait is now available from an external source. An example of masking from class is that some animals lost the ability to synthesize vitamin C as it became externally available from fruits.

In relation to the evolution of human language capability, one hypothesis suggests that as people began to live in groups organized via language, these cultures became the source of survival information. Humans then had an external source for many of the hard-wired instincts that were taking up "neural space" in the brain. Because human brains are underdetermined, this neural space was converted to making humans better at communication, and thus culture. Over time, communication skills began to be seen as fitness indicators and a three-way co evolution of the human brain, more complex culture, and more complicated language developed.