The problem is not a lack of thinking by JW's because all they ever go on about is knowledge, knowledge,knowledge (John 17:3 ad nauseum). The problem is what they think about. Their problem is a lack of considering all sides of the argument. They wilfully choose to only think about what their own leaders feed them.
Methinks that what we're really after is critical thinking skills. It is well-established that meditation, i.e., emptying the mind of thoughts for a period of time, is healthy - it lowers blood-pressure, helps one to sleep, gain clarity, etc.
However, you don't want to be practicing meditation while you're navigating traffic on the freeway!
Likewise, when you are evaluating a "truth" or an "untruth" - a religious belief, for example - you want to be fully alert, using your intellectual capacities to their fullest...............
JWs allow themselves to be put into a trance - ripe for brainwashing....