20-Mile skeptikal argument

[Bonteburger]

Hi!

I usually lurk here and read a little. I don't think I've skipped a Skeptiko episode since its inception in Feb '07 though!

An argument against dog telepathy made me do a mental doubletake - it went along the lines of "well, dogs can hear the individual hum of a car from 20 miles off, you know" but I couldn't find anything on google about it (yet).

I know that Polar bears are supposed to be able to SMELL a seal from 20 mlles away in the binding whiteness of the arctic.

Hearing an approaching car's special whine against the noisy backdrop of a Californian city, hmmm... other story?

250 yards is all I could come up with yet (I'm not very good at imperial but I do know it's a considerably shorter distance). The 20-Mile-debunk argument came up in the youtube comments. Can anyone substantiate this?

If true, it would require that some changes be made to the experiment.

Marco

[Topher Cooper]

It is possible, I suppose though it seems unlikely. An ordinary, running, car engine is roughly the same loudness as human conversation. So we are talking about the ability to hear someone talking at 20 miles away.

I judge it on the edge of plausibility that when measured at the ideal frequency spectrum for a dog, under conditions of complete acoustic shielding a difference of this magnitude at the maximum sensitivity level for dogs might just be discernible by a dog (probably with a high error rate).

The ability to do reliable recognition of such a sound at that level in a natural, noisy environment, with many almost identical sounds seems very implausible to me. It might be worthwhile, though, for someone who is a little less rusty on acoustic physics run the numbers and see what this claim actually amounts to.

[Topher Cooper]

I just did a quick calculation. Assuming I didn't screw it up (a big assumption -- I really don't remember my acoustics unit in physics very well) then this would require dogs to be able to hear sounds 21dB below the threshold of human hearing, or, roughly speaking (so to speak), sounds 100 times lower intensity than humans can hear. I don't know how well dogs can hear relative to humans but I would say that being able to hear 2 or 3 times better than humans would be impressive. Although they can definitely hear sounds higher than we can I have never had any reason to suspect that dogs can hear more than a bit better than we can in our overlapping range.

And of course, the difference between being able to detect a small difference under ideal conditions (what we mean by the threshold of hearing) and being able to reliably differentiate a complex sound from among a cacophony of similar and masking sounds is still apropos -- unless you are planning to conduct your tests in the middle of a deserted arctic ice-field when the air is still and the ice is stable.

[Topher Cooper]

Skimmed the internet some. Here is my impression of the consensus about dogs hearing relative to humans.

First off, there is quite a bit of individual variation, as well as variation by breed, but roughly speaking.

Humans and dogs have roughly the same range of peak frequencies around the few kilohertz range, where there hearing is most sensitive. In this range humans and dogs have about the same sensitivity (with humans winning by a few dB over most breeds). At lower frequencies, again, humans and dogs have roughly the same sensitivities, though dogs may be able to hear slightly lower frequencies than humans can.

At frequencies above the peak region, humans' sensitivity drops off more quickly than dogs' do, and dogs can hear much higher frequencies than can humans -- although not that well, the sounds have to be pretty loud for them to hear them in the ultrasonic range.

Overall, my reading of this is that dogs can hear sounds we can't because of high frequency, but they can't really hear things significantly further than we can. I think anyone claiming that a dog can hear an ordinary car (as opposed to a revved up Formula 1 race car) at 20 miles under natural conditions has quite a claim to back up.

[SkepticalBry]

Originally Posted by Bonteburger

An argument against dog telepathy made me do a mental doubletake - it went along the lines of "well, dogs can hear the individual hum of a car from 20 miles off, you know" but I couldn't find anything on google about it (yet).

Can you cite who made that claim?

Thanks.
-Bryan

[hoggworks]

I agree that the "hearing 20km off" argument holds little water, though I think that you can explain away the phenomena in multiple different ways that don't require your dog to have super-senses.

(Aside from the idea of the dog knowing your pattern, there's also the idea that the dogs are reacting to other things in the neighborhood all the time, and that those things happen to coincide with the return of the owner)

[hoggworks]

I had a thought about this the other day:

Wouldn't a better explanation of how a dog could "hear" the car of its owner be not that dogs have super-hearing, but that the dog hears another car of the same make in the neighborhood? I imagine that could explain a number of visits to the window, as the dog wrongly thinks it's "his" car coming home, but it's just someone else driving around.

Would a believer in Dogs as Psychics imagine that a dog could tell different individual cars of the same make and model apart?

[Open Mind]

Originally Posted by hoggworks

I had a thought about this the other day:

Wouldn't a better explanation of how a dog could "hear" the car of its owner be not that dogs have super-hearing, but that the dog hears another car of the same make in the neighborhood? I imagine that could explain a number of visits to the window, as the dog wrongly thinks it's "his" car coming home, but it's just someone else driving around.

Would a believer in Dogs as Psychics imagine that a dog could tell different individual cars of the same make and model apart?

If anything a potentially confused dog makes the Sheldrake claim stronger .... but ultimately it doesn't matter why a dog goes to window, this doesn't apply to Sheldrake experiment, the last 5 minutes (? can't remember without checking) of journey home was not included (as more plausibly within dog's hearing range). Sheldrake also did some tests with owner coming home in taxi.

[hoggworks]

Originally Posted by Open Mind

If anything a potentially confused dog makes the Sheldrake claim stronger .... but ultimately it doesn't matter why a dog goes to window, this doesn't apply to Sheldrake experiment, the last 5 minutes (? can't remember without checking) of journey home was not included (as more plausibly within dog's hearing range). Sheldrake also did some tests with owner coming home in taxi.

I'm sorry, you're suggesting that a rational, common explanation for a dog's behavior bolsters Sheldrake's claim of an uncommon cause? How does that work?

Are you also seriously suggesting that in an experiment the entire purpose of which is to measure when and why a dog goes to the window (or waiting place) while its owner's away, the reason why a dog goes to the window is unimportant?

As to your point about the last 5 minutes, I'm well aware of it, and I'm also aware of the taxi trips. That wouldn't stop a dog from reacting to the sound of the same type of car driving within audible range of the house. My point is that it might not matter, because the dog would presumably not be able to tell the difference between my VW Golf and the other one of the same year, which happens to be owned by my neighbor two blocks away.

I routinely find myself behind other Golf's in traffic, and not just ones from a decade ago, but same year, same model, same colour. It certainly seems plausible that in a city of any reasonable size (I'm in Guelph, which has about 115,000 people, and I'm at the outer edge of the suburbs, near farmland, so away from the main density of people), that cars which sound close enough to the owners would go by, screwing up the dog.

Add to that the fact that car manufacturers reuse the same engine in multiple models of cars, you've got MASSIVE number of cars which would sound sufficiently like their owners to cause a reaction.

And before you point to the fact that if the dog sees the owner leave in a taxi, they might not be listening for the same car engine sound (which would fall apart, because how many taxis are going to sound alike?), remember that we're talking about dogs. Mr. Pavlov would point to their ability to be conditioned exceptionally well.

[Open Mind]

Originally Posted by hoggworks

Are you also seriously suggesting that in an experiment the entire purpose of which is to measure when and why a dog goes to the window (or waiting place) while its owner's away, the reason why a dog goes to the window is unimportant?

Of course not .... it is unimportant in the sense of whether the dog goes to the window because it hears another dog, the postman, a child kicking a ball ..or your suggestion of a similar sounding car doesn't mean anything more since similar sounding cars do not necessarily arrive home at the same irregular/random times the owner is coming home

No ones knows why a dog goes to the window but the dog ..... but if the dog is going to window more when the owner comes home than at others times when the owner is not coming home .... experimentally over random short, medium or long durations away ...then the dog is most probably reacting consciously or unconsciously to what the owner is thinking or planning to do.

I routinely find myself behind other Golf's in traffic, and not just ones from a decade ago, but same year, same model, same colour. It certainly seems plausible that in a city of any reasonable size (I'm in Guelph, which has about 115,000 people, and I'm at the outer edge of the suburbs, near farmland, so away from the main density of people), that cars which sound close enough to the owners would go by, screwing up the dog. Add to that the fact that car manufacturers reuse the same engine in multiple models of cars, you've got MASSIVE number of cars which would sound sufficiently like their owners to cause a reaction.

Maybe so but it is all irrelevent. It would be a cause of the dog being unsuccessful only, increased noise .... . as similar cars going past have to coincide with the owner coming home at irregular short, medium and long durations away to explain the data.

And before you point to the fact that if the dog sees the owner leave in a taxi, they might not be listening for the same car engine sound (which would fall apart, because how many taxis are going to sound alike?),

The dog owner came home in a taxi, the owner didn't leave in a taxi.