Mirror neurons decides the maturity and intelligence

Mirror neurons is the way we acquire knowledge from the environment or others. We badly need to feel how others feel in each scenarios posed. So those who cry watching a movie are really intelligent since their mirror neurons works good. Of course, this only part of intelligence - the emotional side. Then you need to create the abstract lesson from the felt experience. Then you need to remember it. So mirror neurons + abstraction facility + memory makes a mature, empathic, intelligent being.

Abstraction and memory are there in animals however, mirror must be low in them. The mirror neurons gives us the shared experience and thus a society - superior form of intelligence. Thus we know what can make others better and when everybody does that everybody feels better - an implicit knowledge.

High pitch is question; low pitch is its answer

Observe some instrumental music:

The notes that ascend are like a question being posed at.
and the following low pitch is the answer.

So musicians can use this 'fact' to create better music for some lyrics.
We can analyze bird/animal sounds assuming this.

Update:

Some more thoughts. The correlation with pitch and emotion it evokes would be due to doplar effect. When pitch increases we know that something is coming closer. When it decreases, it is moving away.

To moving away mind must be attaching many correlations like something leaving us, we give something to others - empathy, vastness etc.

On the reverse, the high pitch must be indicating the attachment - something close to us. Something we achieved or obtained.

Laughing sound is the most animal like sound we make

Laughing and crying must be very very old and older than the language. Try observing laughs in a group of people as if you are observing a group of animals. You would notice that laugh is like an animal sound - say hyena :)