Nordbayern.de (Gemany):
Forscher erklart: So werden Sie endlich richtig glucklich/Researcher explains: This is how you finally become really happy
28 October 2017
It was a book that sparked him in 2005, "which absolutely fascinated me," titled "The Happy Company" by British economist and author Sir Richard Layard. Especially a caricature in it gave him something to think about. You can see two dogs. One says to the other: "I have everything: plenty of food and your own hut with garden, but somehow I'm still not happy."
Related publications
Happiness: Lessons from a New Science, Richard Layard, Penguin, 2005. 2nd Edition 2011.