Daniel Levitin - The brain has an attentional mode called the "mind wandering mode" that was

The brain has an attentional mode called the "mind wandering mode" that was only recently identified. This is when thoughts move seamlessly from one to another, often to unrelated thoughts, without you controlling where they go. This brain state acts as a neural reset button, allowing us to come back to our work with a refreshed perspective. Different people find they enter this mode in different ways: reading, a walk in nature, looking at art, meditating, and napping. A 15-minute nap can produce the equivalent of a 10-point boost in IQ.

- Daniel Levitin

source: "Daniel J. Levitin Q&A: 'We've created more information in the past few years than in all of human history before us'". Interview with Lisa O'Kelly, www.theguardian.com. January 18, 2015.