What Pigs and Squirrels Can Teach Us About Managing Pain

Over the past several decades, there have been many supporting studies of the health-promoting effects of an optimistic personality. Much research has been done on the connection between a high level of optimism and good health, described well in clinical psychologists Burel R. Goodin and Hailey W. Bulls' 2014 research paper, appropriately titled, “Optimism and the Experience of Pain: Benefits of Seeing the Glass as Half Full.” The authors state that optimism “is linked to both enhanced physiological recovery and psychosocial adjustment to coronary artery bypass surgery, bone marrow transplant, postpartum depression, traumatic brain injury, Alzheimer’s disease, lung cancer, breast cancer, and failed in vitro fertilization.”

Newer research demonstrates that high levels of hope have been found to be related to lower levels of pain, psychological distress, and functional disability in patients with chronic illnesses. I notice these associations daily when I see patients, and so my clinical style is to be an optimist. I don’t want to give false hope, but I think a major role of a physician is to educate patients about the possibilities for treating their diseases, both those that are available now and those that may be available in the near future. I know it is demoralizing as a patient to feel out of control, but by ensuring patients understand what is going on, I hope I can at least reduce some stress—and perhaps even enable them to have a better outcome through their new optimism.

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This is not to say there’s no value in grief and feeling glum. Forced optimism can backfire when too much inauthentic positivity leads to denialism and hiding dark emotions that demand we process them. Your mood and general outlook on life are not mutually exclusive. But the two do interact to help determine your overall personality and approach to life in response to positive or negative events. Unsurprisingly, this is also true for other members of the animal kingdom, particularly for pigs and squirrels.

In fact, the domestic pig is an interesting animal to study and compare with humans in terms of the way they process happiness and pain. Pigs are among a growing list of research subjects in the relatively young scientific field of animal personality. Pigs share a number of cognitive capacities with humans, such as self-awareness, experiencing emotions, and playfulness. Studies on the domestic pig tell us that mood and personality interact to influence thinking, how our biases come into play within our environment, and decision-making. And therein lies a key word: environment. It turns out that our environments can make or break our moods (and those of pigs).

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In pigs, personality is frequently measured by watching how the animals cope under different circumstances. Pigs that are deemed proactive, characterized by more active and consistent behavior, are not the same as reactive pigs that behave more passively and erratically. In studies on humans, proactivity and reactivity have been linked to extraversion and neuroticism, respectively, with extroverts more optimistic and those with neurotic tendencies more pessimistic. In one particularly illuminating 2016 study done by a group of researchers in the United Kingdom who specialize in animal behavior and welfare, a litter of pigs that included both proactive and reactive swine was placed in one of two environments known to influence their moods. One environment, designed to be more feel-goody, was more comfortable, playful, and roomy than the other. It had a couple of more square feet per pig and the addition of straw, which pigs love to play with and use as their bedding. Research has long shown that the addition of straw to a pigpen can enhance pigs’ welfare.

To conduct the experiment, the pigs were trained to associate two separate feeding bowls with different outcomes. One bowl contained sugary treats, which represented a positive outcome, and the other, filled with coffee beans, promoted the negative outcome.

Then the researchers introduced a third bowl that would act as the litmus test for identifying how optimistic or pessimistic each pig was. The researchers watched to see whether the pig approached this bowl expecting more sweets (and thus another positive outcome) and were optimists. As it turned out, the proactive pigs were more likely to respond optimistically regardless, but the optimism of the reactive pigs hinged on their moods. Reactive pigs living in the roomier feel-good environment were much more likely to be optimistic about the feeding bowl with an unknown inside. The pigs living in a smaller, more barren environment acted pessimistically. The experiment also revealed what the researchers assumed was true from the start: humans are not unique in combining longer-term personality traits, such as a penchant to have a gloomy or conversely sunny outlook, with shorter-term mood biases when making judgments.

Our personalities color our decisions, and our moods can be influenced heavily by our environments, which means we do have some control in protecting our preferred moods. If you want to tip the scales in favor of being hopeful and reap the health rewards, you need to be mindful of your living quarters, what (and most definitely, whom) you surround yourself with, and where you spend your leisure time (watching TV alone in your living room or taking a walk with a friend). This advice may sound obvious or trite, but not until recently has science really drilled down on the significance of the personality-mood-outlook-outcome phenomenon.

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Other scientists have recorded findings in squirrels that point out once again that personality matters. A three-year study published in 2021 that was done by a team of researchers from the University of California, Davis and the Rocky Mountain Biological Laboratory in Colorado is the first to document personality in golden-mantled ground squirrels, which are common across the western United States and parts of Canada. The researchers recorded four main traits: boldness, aggressiveness, activity level, and sociability. They noted that bolder, more social squirrels earn an advantage over their shyer counterparts; the gregarious ones move more quickly, command the use of more space and places to perch themselves, and gain more access to resources. These effects ultimately favor the social squirrels’ survival. It pays to be convivial, and maybe a little brash.

Although pain and pain management within the context of personality was not part of this study, we can draw some conclusions nevertheless. There is a lot that each of us has control over, and many things, such as health, where we have only partial control, so we have to use the power we have to tip the scales in our favor. This means taking a good look at our lifestyles, because work on the things that we can affect—our moods, our environments, whom we associate with, where we choose to spend our time—and the other aspects like pain and how we feel will improve. Maybe it will not alleviate all of our symptoms, but it will have a major influence.

New research into people with personality disorders, such as narcissism and borderline personality disorder, finds they report higher levels of pain and may even be at a higher risk for cognitive decline (and dementias, including Alzheimer’s). This newer research too highlights the power of personality. In particular, the research shows that people who are organized, responsible, goal directed, and gregarious and have high levels of self-discipline (“conscientiousness”) may be less likely to develop cognitive decline and impairments than those who are moody or emotionally unstable (“neurotic”). My hunch is the research on pain and personality and cognition and personality will increasingly overlap. After all, our patterns of thinking and behaving—our personality traits—all go hand in hand with how we perceive pain and how our brains function.

Adapted from THE BOOK OF ANIMAL SECRETS: Nature’s Lessons for a Long and Happy Life by David B. Agus, MD. Copyright © 2023 by Dr. David B. Agus. Excerpted with permission by Simon & Schuster, a Division of Simon & Schuster, Inc.