What two reasons does the author of "What the Brain Says about Maturity" give to explain why brain development is not used to determine when adulthood begins?

The reasons which the author of "what the Brain says about Maturity" which explained why brain development is not used to determine when adulthood begins include:

1. Different brain regions and systems mature along different timetables.

2. Science has never had much of an influence on these sorts of decisions.

Explanation:

In What the brain says about maturity, the author believed that there are 2 different reasons which explains why brain development does not determine when adulthood begins.

For example, an 18 year old can give informed medical advice when compared with adults but might be lacking (immature) when it comes to criminal responsibility. Another, is the situation whereby the maturity required to operate a car or face combat exceeds that required to handle inappropriate movies or drinking.