Dog Science

Last night my wife and I proudly reaffirmed our nerdiness to ourselves and to the world by ditching our friends’ gathering at the local watering-hole – where the moving video image of some very important sporting match between two teams whose names I can’t quite remember was being screamed at – and trekked over to a pet store in Williamsburg to watch a lecture by a dog scientist. Yup, Julie Hecht is her name, MSc is her title, and Applied Animal Behavior with The Family Dog Project is her field. (Check out her blog, Dogspies, on my blog list.) Basically, she studies the science behind man’s best friend, and I think that’s pretty cool. Oh – and there was wine at the lecture! They never served wine where I went to school.
During the talk the audience was tested on whether we could identify the differences between dogs’ barks in various contexts – like attention-seeking, playing, alerting us to the presence of an intruder, asking for a ball to be thrown, about to be walked, and being trained (I was amazed at how well most of us could identify the differences!). We were shown research about the “guilty look” (working conclusion: dogs show the guilty look only when they believe they’re going to be punished, independently of whether or not they’ve done anything wrong). And we learned that dogs look primarily to the right side of our faces to detect our emotions (so-called “left gaze bias”; humans do it too).
We also took this fun little test. Look at the following picture from a dog’s perspective:
What will a dog notice when standing here?
(a) path; (b) bushes; (c) grass; (d) brick wall
If a dog were to walk up to this scene, what would he first notice and want to pay attention to? The path? The bushes? The grass? The brick wall? (This wasn’t the exact picture Julie used, but it gets the point across.)
The answer is (d), the brick wall – because that’s what the dog is going to smell first. Point being, humans don’t always see things (or smell things) the same way dogs do. We have only 5 million smell receptors in our little human noses, while dogs have 44 times more (220 million) in theirs. 
The most thought-provoking part of the lecture to me was a study done on “asymmetric tail-wagging” as responses to different “emotive stimuli”. Basically, bunches of dogs were introduced to things that they were assumed to either like or not like: their owners (like); an unknown dominant dog (not like); and a cat (like). (Wait a minute; why does the cat count as something a dog likes? Well, in this context “likes” is being interpreted as “wants to approach”. And yeah, my greyhound really wants to approach our next-door neighbor’s cat. Though perhaps in not such a casual manner as to be called “approach”; more like ATTACK! But he’ll certainly be happy to do so.) 
In each case, the dog’s tail was measured to see whether its wag had a directional “bias” – i.e., whether it was wagging more to the left or more to the right. And in a statistically significant number of cases, the
Fig. A: wagging to the right; Fig. B: wagging to the left

dogs’ tails wagged a statistically significant amount more to the right when the dogs saw their owners or (to a lesser degree) the cat, while their tails wagged more to the left when the dogs saw the unknown dominant dog. Conclusion: a right-wag means happy (“Approach!”); a left-wag means unhappy (“Retreat!”)

I thought this was really cool, first of all just because people are actually setting up labratory studies with dogs wagging their tails in them (labs with labs)? But also for the implications about understanding dog body-language. Anyone who works with aggressive or temperamental dogs knows that wagging can’t always be interpreted in the naive way it often is by the general population: wagging means excitement, or stimulation, not just happiness; so a dog wagging its tail isn’t necessarily any more friendly and approachable than a dog that isn’t wagging. So if these studies can really be trusted – if I can in general feel more comfortable with a dog who’s wagging more to the right than to the left, and if I should in general be cautious around a dog who’s wagging more to the left than to the right – that’s really helpful info. (Caveat, though: I’d hate to be the cat who makes that generalization when it sees my greyhound approaching while wagging mightily rightily.)

I had a few questions about the study, though, and when I started to try to answer the questions on my own I quickly realized how difficult science really is. The interpretation of the study was presented as being based on a combination of two assumptions about the “lateralization” of the brain:

1. the left side of the brain controls the right side of the body, and the right side of the brain controls the left side of the body; and
2. the left side of the brain processes more “positive” emotions, while the right side processes more “negative” ones.

Combine those two assumptions and you get the conclusion that the right side of the body should be more involved in expressing negative emotions, while the left side of the body is more involved in expressing positive ones. This is what was supposedly supported in dogs by the results of the directional wagging test.

What I wanted to know is: when a dog wags to the right, does that mean it is using the right side of its body? This is a physiological question: to wag its tail, does a dog “pull” the tail to one side (e.g. to the left with its lefthand tail muscles, whatever those are) or does it “push” it (to the left with its righthand muscles)? Or does it do both equally, simultaneously? If a righthand wag doesn’t mean more righthand musculature is being used, then I don’t see how the results of the directional wagging test can be seen as having anything like the meaning that’s being ascribed to them.

Again, this is a physiological question, to be answered by biologists who know canine musculature; so I thought I’d read a little bit about it. Well, I started to find things like this:

As to the cross-over of descending motor pathways, in dogs the rubrospinal tract is the predominantly volitional pathway from the brain to the spinal cord; the pathway decussates just caudal on the red nucleus and descends in the controlateral lateral funiculus; fibres of the rubrospinal tract terminate on interneurons at all levels of the spinal cord. (See Buxton, D.F., and Goodman, D.C. (1967). Motor function and the corticospinal tracts in the dog and raccoon. J. Comp. Neurol. 129, 341–360.)

Oops. I ain’t get gotten what duz bein sedded.

So I’ll just leave it at this:  there’s some really cool research being done on how dogs communicate; and tail-wagging may be more complex and expressive than we’ve previously thought.

Oh yeah – and science is cool.  🙂


Leave A Comment