The Rabbit Effect

What do rabbits have to do with mental health? In her recent book, The Rabbit Effect: Live Longer, Happier, and Healthier with the Groundbreaking Science of Kindness, Columbia psychiatrist Dr. Kelli Harding makes the connection quite clearly.

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We were fortunate to have Kelli join us for a Zoom discussion of her book yesterday to launch our inaugural Health and Aging Policy Fellows book club. With kindness on full display, here are five highlights from a book filled with many more personal stories and wise learning.


1.

The kind lab assistant. The title of Dr. Harding’s book derives from an accident in Dr. Robert Nerem’s lab in 1978. They were studying the relationship between a high-fat diet and heart health with the help of a group of New Zealand White rabbits. After feeding the rabbits a diet high in fat, Dr. Nerem and colleagues analyzed the number of fatty deposits in the rabbits’ small blood vessels – expecting that all the rabbits would have fatty deposits that were commensurate with their high cholesterol levels. To their surprise, one group of rabbits did not. Befuddled, they explored many alternative hypotheses. Ultimately, they determined that the group of rabbits with far healthier blood vessels was under the care of an especially kind post-doctoral student who treated the animals with love and patience when handling them. Really. The findings have been replicated. Kindness is good for our health.

2.

Kindness creates community. An essential correlate of kindness is community. We increasingly recognize that community is a central factor in the social determinants of health. We know that our zip codes predict more about our health status than we might ever have imagined. Dr. Harding elegantly connects the big ideas of public health and social policy to each of us personally. We know social isolation and loneliness can be fatal. We know that strong, socially connected communities are good for our health. and we know that simple acts of kindness – greeting our neighbors, picking up our trash, demonstrating patience with an older adult crossing the street – build community. In other words, we don’t have to wait for big policy shifts to create positive public health benefits for our health and mental health. We can replicate the Rabbit Effect in our everyday lives.

3.

The Prisoner’s Dilemma. Of course, it’s simple and not so simple, and Dr. Harding knows the complexities well from her own experiences and the personal stories of the many people she has cared for in the psychiatric emergency room at New York-Presbyterian Hospital. This is where the Prisoner’s Dilemma is illustrative. In this classic psychology paradigm, two individuals from a gang become prisoners. They are not allowed to communicate with each other. The prosecutors present them with an opportunity for a lesser sentence if they testify that the other gang member committed the crime. Alternatively they can choose to cooperate with the other by remaining silent. The best outcome depends on cooperative behavior between the two prisoners, which hinges on a high degree of trust. And that’s where we get to mental health implications once again.

4.

Trust. The prisoner’s dilemma paradigm has many permutations. The one most relevant to us is that the basic studies show that we humans have a natural tendency toward cooperative behavior when trust is high. People tend to choose outcomes that are not exclusively in their own interest but rather in the collective interest when trust is high. But when trust is low and we are fearful that others are not on our side or even out to get us, kindness goes out the window, cooperation breaks down, communities collapse, mental health problems increase. Prospective data indicate that as levels of interpersonal trust decline, risk for developing mental disorder increases.

5.

Kindness is not a cure-all. Dr. Harding is careful to acknowledge that kindness is not a bulletproof vest that protects us against all harm and hurt in life. Bad things still happen to good and kind people. However, all the way down to our cells and up to the larger fabric of society, kindness serves to build strength and coping and promotes health. It can be mapped in our brains and measured in our cells as much as it can be seen on the streets of our neighborhoods. Kindness promotes healthy brain development. Kindness builds social connectedness. Kindness prepares children to learn. And when adversity strikes, we have layers of resilience and networks of support that promote quality of life even in trying times.


The Rabbit Effect by Kelli Harding is an inspired book. Founded on scientific evidence and filled out with all kinds of life experiences, Dr. Harding makes a compelling case that kindness has the potential to promote health and mental health not only for rabbits, but for us all.

Kathleen M. Pike, PhD

Kathleen M. Pike, PhD

Kathleen M. Pike, PhD is Professor of Psychology and Director of the Global Mental Health WHO Collaborating Centre at Columbia University
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