The article at the link below isn't particularly scientific, but it speaks from the heart about the importance of human touch the basic development of children, and then questions how we move away from that as adults.
In other cultures, such as India, it's not uncommon to see groups of adults of the same gender holding hands as they walk. We are only beginning to discover the incredible healing power, and health maintaining benefits of this everyday, casual human touch.
http://www.heraldscotland.com/opinion/14624160.Val_Burns__A_kiss_isn_t_just_a_kiss_thanks_to_the_power_of_human_touch/