The idea that “happiness is good for you” might sound like a truism, but it raises some complicated questions. It’s not necessarily the case that happiness has to be good for your health; it could simply be a pleasant feeling with no other significant impact. Why should smiling translate into a stronger immune system or longer life?
To understand whether a good mood generally enhances physical health over the years, you need to find scientific experiments that connect concrete happiness outcomes to concrete health outcomes. Neither is particularly straightforward to measure, so compelling research on this topic is pretty scarce. But since 2020, efforts have started to pick up. I’ll focus on two specific questions here:
- Is happiness associated with less age-related memory decline?
- Can actively boosting happiness improve health outcomes?
Happiness is linked to slower memory decline
In a study published in 2020, Emily Hittner and her academic colleagues analyzed data from an 18-year longitudinal study that started in the mid-1990s and ended in the mid-2010s (most participants in the study were aged 40–60). At three timepoints, each separated by nine years, the researchers collected data on people’s “positive affect”, which basically means their levels of good mood. Referring to the last 30 days of their life, people had to report how much they had experienced feelings such as “enthusiastic”, “cheerful”, “calm and peaceful”, and “in good spirits”.
At the second and third timepoints, researchers also collected data on memory performance. This involved a telephone-based test in which people had to listen to a list of 15 unrelated words and then recall as many as possible within 90 seconds.
The data first confirmed two simple patterns:
- As expected, memory declines with age.
- Positive affect (happiness) increases with age.
The second pattern is only true because the participant sample mostly contained middle-aged and older people. When you include…