Thursday, May 27, 2010

The empathetic vegetarian brain

It is often the case that meatless lifestyles are chosen for ethical reasons related to valuing animal rights. As a consequence of their food choices, vegetarians and vegans are often accused of and taunted for loving animals more than people. But do most vegetarians care less for fellow humans than animals, care for humans and animals equally, or care more for humans than animals but still care more for animals than omnivores do?

A study published yesterday in PLoS ONE has attempted to parse out differences among omnivores, vegetarians and vegans in brain responses to human and animal suffering. The three groups were first given the Empathy quotient questionnaire, and it was determined that vegans and vegetarians scored significantly higher in empathy than omnivores. Next, the subjects had their brains scanned with fMRI as they viewed images of human suffering, animal suffering and “neutral” natural landscapes. Many differences were found among the brains of those with different feedings habits.

Firstly, vegetarians and vegans had higher engagement than omnivores of “empathy related areas,” such as the anterior cingulate cortex (ACC) and left inferior frontal gyrus (IFG), while observing both human and animal suffering. This seems to suggest that there is a neural basis for those with meatless lifestyles having greater empathy for all living beings.

However, when viewing animal suffering but not human suffering, meat-free subjects recruited additional empathy related areas in prefrontal and visual areas and reduced their right amygdala activity. This may be interpreted as evidence that vegetarians and vegans care more about the emotions of animals than those of humans. It is important to consider how the study was conducted, though, before reaching such a conclusion.

The authors themselves note a couple of weaknesses in their design. The subjects’ brain activities while they viewed human or animal suffering were compared to the baseline/control condition of “neutral” scenes that did not include living beings, faces, or suffering of any kind, which are all factors that should have been considered. The subjects were also simply asked to look at the images of the different conditions without being asked about their thoughts or feelings, so it is impossible to confidently attribute their brain responses to specific emotions. But even if the demonstrated brain activity represented empathy, there is also the possibility that the subjects were desensitized to images of human suffering that appear daily on the news. Desensitization to an image does not necessarily reflect empathetic feelings toward fellow humans. So a claim that vegetarians/vegans love animals more than humans because they have more empathetic neural activity while viewing suffering animals than suffering humans is unsubstantiated at this point.

Another major finding in this study was differences in neural representations of cognitive empathy between vegetarians and vegans. All of these subjects had chosen not to eat meat for ethical reasons, but the authors suggest that these differences in vegan and vegetarian brain responses indicate that the groups experience empathy for suffering differently, possibly due to differences in reasons for their diet choices. Again, these results should be taken as preliminary because of weaknesses in the study’s design.

Overall the study is interesting, but it remains to be seen whether this will spark further research that will ultimately demonstrate findings significant enough to affect public policy and animal cruelty regulations. For now, we have a bit of a clearer picture of the brain’s representation of empathy and a lot of extra material for the never-ending ethical debate over man’s right to meat.
Filippi M, Riccitelli G, Falini A, Di Salle F, Vuilleumier P, Comi G, & Rocca MA (2010). The Brain Functional Networks Associated to Human and Animal Suffering Differ among Omnivores, Vegetarians and Vegans PLoS ONE


  1. I'm not sure the comment regarding desensitization makes sense given that they're comparing the difference in empathy for human and animal suffering between two subject groups and both groups should theoretically have the same desensitization effects for humans but not animals

  2. True, both groups should have the same desensitization effects for human suffering. But this indicates that directly comparing our feelings of animal suffering to human suffering is flawed. Different neural networks for empathy involved in viewing the two stimuli may simply reflect these fundamental differences and not increased empathy toward animals. Also, the subjects weren't even asked if they feel more empathetic toward animals or humans.

  3. My first thought was that the addition regions may activate in response to animals simply because it takes more brain activity to process the situation of a nonhuman; like recognizing a human crying happens easily, but there's more thought involved in recognizing a dog's cringe.

  4. I know nothing about the science of this, but am just wondering what might result from the combination of a) a repeat study with weaknesses addressed, and b) the sort of galvanic skin response data gathered in a 'lie detector' test? Might help clarify degree vs type/pathway of response and other questions. (And as for the human-cry vs dog-cringe, respectfully, I can't agree at all that the former empathy 'happens [more] easily'; it's that very question which this new study helps to explore, and high time in my personal opinion.)

  5. this study is not totally right and not totally wrong, well I mean this because I like to eat meat, but this don't mean that I'm totally careless about the animal suffering, actually the animal abuse is one of the thing that provoke more rage, for that reason I join to Kamagra, a organization that promoved the animal care.

  6. Interesting thesis indeed but I do not quiet understand what difference it makes if I care more about humans or animals. I guess you should care as much about animals as about humans and I am sure people that chose eating no animals because of ethical reason have a high empathy for humans as well.


  7. I thought that yoga had increased my empathy and caused my 99% vegetarianism (for reasons of not really preferring meat, ever, but I won't refuse a gift of food just because it is meat.)

    Maybe the yoga caused the diet change and that in turn helped the empathy. Thank you :)