ResearchBlogging.orgHumans are naturally omnivorous, our digestive system is adapted to cope with both animal and vegetable matter. Obviously we can’t eat everything, we wouldn’t get as much sustenance out of a mouthful of grass as a cow does. Termites can deal with the high cellulose content of wood and derive energy from that source while we would starve on such a diet. On the whole however we can manage to survive on a wide range of foodstuffs1,2 and can be quite happy doing so.

So far, so good. What on Earth has this got to do with empathy? Well, a recent study published in PLoS One using fMRI looked at the brains of subjects while they viewed negative images of either humans or other animals3 here is the reasoning from the study authors.

“In this study, we postulated that the neural representation of conditions of abuse and suffering might be different among subjects who made different feeding choice due to ethical reasons, and thus result in the engagement of different components of the brain networks associated with empathy and social cognition.”

The thinking here is that individuals who choose a vegetarian or vegan lifestyle based on ethical considerations4 have a higher degree of empathy towards the suffering of both humans and animals compared to individuals who continue with an omnivorous diet. It might be of use to first define what empathy means in the context of this work, and why paraphrase when the authors have put it in their own words so much more concisely5:

“Empathy toward another person, which can be defined as the ability to share the other person’s feeling in an embodied manner, has been related to recruitment of a network mostly including the somatosensory and insular cortices, limbic regions and the anterior cingulate cortex (ACC).”

The study did find increased activation of those brain areas that correlate with empathy in vegans and vegetarians. In fact it was also found that vegans and vegetarians had much higher activation of these areas while watching images of animal suffering than human suffering implying greater empathy for animals than humans. As noted in the study:

“Remarkably, vegetarians and vegans have an higher engagement of empathy related areas while observing negative scenes regarding animals rather than humans, with the additional recruitment of the mPFC, PCC, and some visual areas. ACC has been associated with alert states, self awareness and pain processing, whereas mPFC and PCC activations are frequently observed in conditions involving representation of the self and self values …the selective response of vegans to animals in the ACC (with reduced amygdala responses) might reflect a greater attribution of self-relevance and a greater recruitment of emotional regulation mechanisms, when viewing negative states of non-human beings… By contrast, omnivores, showed greater responses to human negative valence scenes in the ACC (together with reduced amygdala activation), suggesting that self-relevance and emotion control mechanisms were more specifically engaged by viewing suffering conspecifics than suffering animal beings.”

This suggests to me that vegans are actually incorporating their greater empathy toward non-human animals into their personal identity (self-relevance). Possibly elevating it to a defining characteristic of their personality. This makes sense to me as in today’s world, while vegetarianism is becoming more common, the social pressure against a vegan lifestyle in most places would still be considerable. To retain such a choice in the face of this pressure would require a great deal of commitment.

This is pure speculation on my part but in the context of omnivores showing greater self-relevance activation when viewing negative scenes involving humans it appears to be a reasonable conjecture. This being a correlational study however there is no way to determine the causation of such responses. Do naturally highly empathic individuals simply gravitate to vegetarian or vegan lifestyles or does choosing the diet cause greater empathy, possibly as a means of rationalising a choice which may have originally been made for other reasons6.

Either way, this study implies that we omnivores are cold hearted in comparison to our meatless compatriots. How this might impact other decisions in our lives I’m not sure, perhaps an interesting follow-up would be if vegetarians and vegans give more time/money to charities or perceived worthy causes outside of the animal welfare realm. Actually this reminds me of a woman I occasionally see holding up a sign outside of the supermarket. Upon the sign is written “Compassion begins with dinner”7. Perhaps she’s onto something.

1. This is obviously a tautology, sorry about that.

2. Can’t be out done by my blogging colleagues, no mere footnotes for me. Linked footnotes is where it’s at.

3. I get quite uncomfortable making the arbitrary distinction between humans and animals.

4. As opposed to the “Meat is icky” reason.

5. Who says there’s no advantage to laziness?

6. See note 4.

7. Or some such thing, who am I, Rainman? I can’t remember everything.

Filippi, M., Riccitelli, G., Falini, A., Di Salle, F., Vuilleumier, P., Comi, G., & Rocca, M. (2010). The Brain Functional Networks Associated to Human and Animal Suffering Differ among Omnivores, Vegetarians and Vegans PLoS ONE, 5 (5) DOI: 10.1371/journal.pone.0010847

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