John Lennon wasn't wrong: certain meditation techniques can indeed make our attention open up or focus on one single thing. This is the outcome of a study that we carried out at the Leiden Institute of Brain and Cognition with Matthijs Baas, fellow researcher from the University of Amsterdam

Different meditation types, different effects
We were the first to investigate whether meditation has an immediate effect on behavior, even in people who have never meditated before. There are two fundamental types of meditation that affect us differently: open monitor meditation (which involves being receptive to every thought and sensation) and focused attention meditation (which entails focusing on a particular thought or object).

Study design
40 people naïve to meditation participated in our study. Half of the people practiced open monitor meditation while the other half practiced focused attention meditation for 20 minutes, respectively. After meditating, we asked participants to perform a task during which they were required to pay attention to two numbers in a rapid stream of letters presented on a computer screen.

Meditation optimizes adaptive behavior
Compared to participants who performed focused attention meditation, people who performed open monitor meditation were significantly better in paying attention to the two numbers. Even if preliminary, these results provide the first evidence that meditation affects our mind instantly, even without any practice! As such, our findings shed an interesting new light on the potential of meditation for optimizing how people allocate their attention when processing temporally extended events—like in real life.

Colzato, L.S., Sellaro, R., Samara, I., Baas, M., & Hommel, B. (2015). Meditation-induced states predict attentional control over time. Consciousness and Cognition, 37, 57-62.