Thomas Jefferson called happiness a pursuit. Philosopher Denis Diderot called it a passion. The Beatles called it a warm gun. And scientists, like Dr. Ed Diener (“Dr. Happiness”), have searched for what makes us happy and what good happiness brings us.

Now, UCLA researchers have discovered that the answer to the latter lies in the former: It’s the reason for the happiness that determines how the state of mind affects us. Steven Cole, professor of psychiatry and behavioral sciences, along with UCLA researchers Jesusa M.G. Arevalo and Jeffrey Ma and scientists from the University of North Carolina recently found that different forms of happiness induce distinct biological responses.

Their research revolved around two forms of a feeling of well-being: eudaimonic, which comes from having a deep sense of meaning and purpose in life and doing good for others, and hedonic, which grows out of self-gratification and pleasure-seeking. Buying a new car for the thrill of it, spending money on luxurious things, indulging in luxuries just because they feel good — these define a hedonic sense of happiness.

Using a questionnaire, the researchers assessed the level of both types of happiness in 80 individuals. Then Cole and his team took blood samples from the participants in the study and examined which genes were turned on or off in the cells of each person’s immune system.

They found that individuals with a strong sense of hedonic well-being showed high inflammatory gene expression and low expression of antiviral and antibody genes — meaning that their reaction to adversity would be similar to that of people under stress and anxiety.

According to Cole, the senior author of the study, this type of reaction can promote inflammation and cause cardiovascular, neurodegenerative and other diseases and can impair resistance to viral infections.

In stark contrast, individuals with a strong level of eudaimonic well-being had the exact opposite traits. They were happy and, genetically, they were healthy. But both types of individuals “seemed to have the same high levels of positive emotion” and their “emotional states were similarly positive,” Cole says.

The difference, ultimately, lies in the genes.

What the study — which has been cited by the Atlantic and The Economist magazines — tells us, Cole says, is that doing good and feeling good have very different effects on the human genome, even though they generate similar levels of positive emotion. “Apparently, the human genome is much more sensitive to different ways of achieving happiness than are conscious minds.”

A longer version of this story appears at the UCLA Newsroom at