Cláudia Simão, Beate Seibt, ‘Friendly touch increases gratitude by inducing communal feelings’, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4467067/ , Frontiers in Psychology, US National Library of Medicine NCBI (2015 Jun 15)
A friendly touch can promote gratitude and communal relations concurrently. (…) Gratitude can improve well-being by increasing the appreciation of positive things in life (…) and increasing resilience to negative things. (…) Communal relations and the support they offer are central for well-being and physical health.
Simão C, Seibt B. Friendly touch increases gratitude by inducing communal feelings. Frontiers in Psychology. 2015;6:815. doi:10.3389/fpsyg.2015.00815.