Almost everyone remembers a time someone treated them badly. The memory can come back fast, even years later. It can still sting a little. Some people carry that hurt for a very long time.
Sources
Wade et al., "Efficacy of psychotherapeutic interventions to promote forgiveness: A meta-analysis," Journal of Consulting and Clinical Psychology, 2014
Witvliet, Ludwig & Vander Laan, "Granting forgiveness or harboring grudges," Psychological Science, 2001 — the physiological measurements
Davis et al. (2015) — forgiveness and wellbeing
Everett Worthington, the REACH forgiveness model, and the 2025 REACH randomised trial
Toussaint, Webb, Hirsch, Kohls, Offenbaecher, Dezutter, Nguyen, Vallejo & Sirois, "Forgiveness and Physical Health: A Review of Theory and Evidence", in Sirois (ed.), The Palgrave Handbook of Positive Psychology and Health (2025), pp. 245-268 — https://link.springer.com/chapter/10.1007/978-3-031-89095-6_11 (the 73 studies / ~75% figures. Verified 2026-08-11: these are from the 2025 chapter, NOT the 2005 Handbook they are usually credited to. Abstract wording is "seventy-five percent showed at least one connection between a dimension of forgiveness and a physical health outcome" — a CONNECTION, not a positive link, and PHYSICAL health specifically. Only the open abstract was read; how the 73 were selected is unverified. Do not confuse with Webb, Toussaint & Conway-Williams (2012), J. Health Care Chaplaincy 18(1-2), 57-73, which reviews 54 studies — note that page range ends at 73, a plausible route for the garbled citation.)
Greater Good Science Center, UC Berkeley — forgiveness research summaries
Wade, N. G., Hoyt, W. T., Kidwell, J. E. M., & Worthington, E. L., Jr. (2014). Efficacy of psychotherapeutic interventions to promote forgiveness: A meta-analysis. Journal of Consulting and Clinical Psychology, 82(1), 154-170. https://pubmed.ncbi.nlm.nih.gov/24364794/ (k=53 posttreatment effect sizes, N=2,323, from 54 reports; delta=0.56 vs no-treatment, 0.45 vs alternative treatment)
Witvliet, C. van O., Ludwig, T. E., & Vander Laan, K. L. (2001). Granting forgiveness or harboring grudges: Implications for emotion, physiology, and health. Psychological Science, 12(2), 117-123. https://journals.sagepub.com/doi/10.1111/1467-9280.00320 (71 participants: 35 female, 36 male)
Davis, D. E., Ho, M. Y., Griffin, B. J., et al. (2015). Forgiving the self and physical and mental health correlates: A meta-analytic review. Journal of Counseling Psychology, 62(2), 329-335. https://scholars.cityu.edu.hk/en/publications/forgiving-the-self-and-physical-and-mental-health-correlates-a-me/ (psychological well-being r=.45, k=65, N=17,939; physical health r=.32, k=18, N=5,653)
Ho, M. Y., Worthington, E. L., Jr., Cowden, R. G., et al. (2024). International REACH forgiveness intervention: A multisite randomised controlled trial. BMJ Public Health, 2(1), e000072. https://pmc.ncbi.nlm.nih.gov/articles/PMC11812785/ (N=4,598; ClinicalTrials.gov NCT04257773) - REPLACES the current source line that dates this trial to 2025
Hall, J. H., & Fincham, F. D. (2005). Self-forgiveness: The stepchild of forgiveness research. Journal of Social and Clinical Psychology, 24(5), 621-637 - the quoted title in section 44
American Psychological Association. Forgiveness (APA Dictionary of Psychology entry). https://www.apa.org/topics/forgiveness - the definition used in sections 4 and 11
Greater Good Science Center, UC Berkeley. What is forgiveness? https://greatergood.berkeley.edu/topic/forgiveness/definition - source of the quoted phrase in section 6 and of the forgetting/condoning/excusing distinctions
Worthington, E. L., Jr. (2020). The Science of Forgiveness (white paper, April 2020). John Templeton Foundation. https://www.templeton.org/wp-content/uploads/2020/06/Forgiveness_final.pdf - the citation named in section 11
Toussaint, L., Shields, G. S., Dorn, G., & Slavich, G. M. (2016). Effects of lifetime stress exposure on mental and physical health in young adulthood: How stress degrades and forgiveness protects health. Journal of Health Psychology, 21(6), 1004-1014 - the buffering study in section 39
Freedman, S. (2026, April 27). What we get wrong about teaching kids to apologize and forgive. Greater Good Magazine, UC Berkeley. https://greatergood.berkeley.edu/article/item/what_we_get_wrong_about_teaching_kids_to_apologize_and_forgive - source for section 49; it cites Craig E. Smith et al. (2018) on coerced apologies
International Forgiveness Institute (founded 1994 by Robert Enright, professor of educational psychology, University of Wisconsin-Madison) - the 20-step process model and its four phases (uncovering, decision, work, deepening). https://internationalforgiveness.com/
Read end to end and corrected: August 10, 2026. Numbers checked: August 10, 2026.