Authors:

Observation is like a muscle. It grows stronger with use and atrophies without use. Exercise your observation muscle and you will become a more powerful decoder of the world around you.

Joe Navarro, Marvin Karlins (2009). “What Every BODY is Saying: An Ex-FBI Agent’s Guide to Speed-Reading People”, p.9, Harper Collins
Observation is like a muscle. It grows stronger with use and atrophies without use. Exercise your observation muscle and you will become a more powerful decoder of the world around you.