A wealth of psychology and behavioral research lets us track the life cycle of a good deed.

• Why it matters: An act of kindness can benefit the person who does it, the person who receives it, and even people who witness it or hear about it.

How it works:

1. 🙋 The doer: Volunteering and performing other acts of kindness — from donating blood to smiling at a stranger on the street — benefits the doer, according to an American Psychological Association review of several research papers. The perks include feeling happier and less lonely, anxious and depressed.
2. 💛 The receiver: As we've reported, we tend to underestimate how much a simple gesture, like holding a door, means to the person on the receiving end. Plus, kindness can set off a chain reaction. People who benefit from a good deed are likelier to direct kindness to strangers themselves, Axios' Ashley May reports.
3. 👀 The witness: Just watching someone do something nice helps, in a phenomenon researchers call "moral elevation." The boost people get from witnessing kindness also makes them likelier to spread it.

📰 Even reading about good deeds has an effect: In a 2023 study published in the journal PLOS ONE, people who read news stories about good deeds after reading negative news stories felt uplifted and more inclined to believe in the goodness of others.

What's next: We want to spread the goodness by reviving one of our favorite Finish Line series — sharing the good deeds you encounter with fellow readers.

• Tell us about a random act of kindness you received or witnessed — from a friend, a family member, a neighbor or a total stranger — in 2-3 sentences. Send it to [email protected], along with your name and hometown, and we'll feature the stories in future editions.

Reader Aaron Damiani of Chicago sends this pic from Fort Smith, a small community in southern Montana, about 90 miles southeast of Billings:

• "I snapped this photo this weekend to share with my wife and kids the beauty of the Montana skies in Fort Smith, right as the sun was setting. In the Adirondack chairs are dear friends who were smoking cigars and taking it all in."