Better reception on FM radio

Whats the reason behind the reception becoming clearer and volume increase when a person/some body part comes near the antenna of the FM receiver?

Whats the technical reasoning for this?

Thank you.

When a human body is close to an antenna, could change the multipath trajectory of the waves, and depending by the phase of the two signals (direct or reflected) the reception could be better, but also could be worst.

Also the human body could behave as a capacitive antenna increasing the electromagnetic field at the receiver input.