About these endnotes

This is where we provide references and in-depth information about everything in the Kindness playbook.

Acknowledgements

We honor and thank the scientists and their teams whose research on prosocial behavior, social support, and well-being inspired this Playbook. Any errors or omissions are ours.

How we define this strength

Prosocial behavior—i.e., the opposite of antisocial behavior—is broadly defined as actions undertaken to help others. See Wispé (1972) for one of the earliest usages, and Batson and Powell (2003) and Penner, Dovidio, Piliavin and Schroeder (2005) for more recent perspectives. Typically, prosocial behavior refers to actions that one takes to help others, like pulling a drowning person out of a river or bringing coffee for coworkers. However, as reviewed by social support expert Shelley Taylor (2011), in reality, people regularly give each other numerous kinds of support, including informational support (knowledge sharing and co-processing), instrumental support (tangible help, including favors or resource-sharing), and emotional support (warmly reassuring another person of his or her worth). These types of support introduce the possibility of kind acts based on physical touch, action, sharing, and verbal interaction.

Benefits of kindness

Numerous studies have found a correlation between being kind—for instance, by volunteering or donating—with all sorts of good outcomes, including happiness and decreased mortality (Dunn, Aknin, & Norton, 2008; Glanville, Paxton & Wang, 2016; Gruenwald, Liao, & Seeman, 2012; Post, 2005). An avalanche of experimental work further reveals that, in general, kindness tends to make people feel happy (see Curry, Rowland, Van Lissa, Ziotowitz, McAlaney, & Whitehouse, 2018, for a review).

Peer effects

9- to 11-year-old children instructed to perform three acts of kindness per week (over four weeks) became more popular with their peers than did those who visited three places each week (Layous, Nelson, Oberle, Schonert-Reichl, & Lyubomirsky, 2012).

Self-signaling effects

Less is known about why acts of kindness make people feel happier. However, the most common explanations are based on the notion that human beings have three fundamental psychological needs: they need to believe that they have autonomy, that they are competent, and that they are socially connected (Deci & Ryan, 1985).

First, social interactions with other people play a clear role in the benefits of kindness. One study found that charitable giving only made givers happier when they interacted with a representative of the charity (Aknin, Dunn, Sandstrom, & Norton, 2013). Second, prosocial behavior has been shown to lead individuals to perceive themselves as more competent and autonomous (Chancellor, Margolis, Jacobs Bao, & Lyubomirsky, 2018), thus boosting well-being.

Pulse Check

Paying attention to what other people want or need may be key to effective relationship building. In fact, it is possible that the actual helpfulness of a prosocial act to the recipient may depend on whether it is done with responsiveness—that is, whether the act is a) based on an understanding of the other’s actual needs, b) indicating value and support for the other person, and c) supporting them to fulfill their personal needs and goals (Reis & Clark, 2013).

Considering how much my actions mean to others can help in reframing a negative experience as a positive one. Benefit-finding has been shown to be linked with better well-being and lower depression across many studies (Helgeson, Reynolds, & Tomich, 2006).

Regularly recounting kind acts can be helpful, as some research has found that simply recounting one’s kindnesses has positive effects similar to actually doing more kind acts (Ko, Margolis, Revord, & Lyubomirsky, 2018). Additionally, this might create a positive feedback loop, in which recalling past acts leads to future kind acts (Anik, Aknin, Norton, & Dunn, 2009; Aknin, Dunn, Sandstrom, & Norton, 2013; Layous, Nelson, Kurtz, & Lyubomirsky, 2016).

Making “If ___, then ___” plans can aid in habit formation. Known as “implementation intentions,” plans about what you will do when an opportunity arises can increase the likelihood of achieving these goals (Gollwitzer, 1999; Sheeran, Webb, & Gollwitzer, 2005).