Brian Hand, Upright Downtime: Making Wise Choices about Entertainment (Biblical Discernment for Difficult Issues; Greenville, SC: Bob Jones University Press, 2008), 5–6:

Entertainment is not simply an activity that rests the mind, since many forms of leisure exercise the mind to some extent. For example, in arguing the dangers of television, video games, and music, some writers exaggerate the mental atrophy that occurs. While it is true that these media tend to relax the rational and cognitive processes of the mind (the left hemisphere), they actually tend to strengthen the emotional, subjective, and reactive centers of the brain (the right hemisphere).