5 ms·

from the paper -- https://frontiersinzoology.biomedcentral.com/track/pdf/10.1186/1742-9994-10-80 https://frontiersinzoology.biomedcentral.com/track/pdf/10.11...

from the paper -- https://frontiersinzoology.biomedcentral.com/track/pdf/10.1186/1742-9994-10-80 https://frontiersinzoology.biomedcentral.com/track/pdf/10.11... Typically, the daily declination comprises westwardshifts in the morning and eastward-shifts in the afternoon, while the magnetic field is rather stable at night [21,22]. This calls for necessity to test whether the dog alignment is not actually influenced primarily by time of the day and most probably by position of the sun on the sky. We can, however, exclude this alternative. First, days when the magnetic field parameters change erratically and unpredictably (i.e., magnetic storms) are quite frequent. These changes have been well studied by others and are described in the literature (cf. [21,22] for reviews). Second, the data collection was not biased to either morning or afternoon (Table 8). Third, periods of sampling under conditions of quiet magnetic field were rather evenly distributed in the course of the day. Fourth, and most importantly, alignment during excreting was apparent under conditions of quiet magnet field, irrespective of the time of day or month. Time of day per se was not a reliable predictor of expression of alignment (Figure 2, Tables 3, 9). Fifth, generally, there are on average 1,450 sunshine hours per year at maximum in the Czech Republic and in Germany, on localities where measurements were done. Even if we would assume that these sunshine hours were evenly distributed over the daylight period and the year (as our observations were), there would only be a probability of 33% that the observation was made when the sun was visible. Hence, with high probability (67%) most walks during the daylight period were made when it was cloudy. Last but not least, the argument that the dogs might orient with regard to sun position so that they turn with their back to the sun in order to avoid dazzling by sunshine during such a sensitive and vulnerable act as excretion can be questioned. This argument is not plausible for urine marking, which is a brief act. We doubt that a dog that cares of not being attacked would always make sure to be turned away from the sun. The dog will likely look in that direction from where danger can most probably be expected - and this is for sure not always the direction away from the sun. In contrast to a human, the dog is relying also on its nose and its ears (in some breeds even more than on its eyes) when monitoring its surroundings - so we may expect that the dog heads with its nose and pinnae against the wind or in the direction of interest. Directing the pinnae and the nose may take priority over eyes. One can also often observe that dogs (especially during defecation) align in a certain direction, which is actually a different one from the direction of interest and they turn their head then in that other direction. Also we have to take into account that dogs are smaller than humans, they look at a different angle over the horizon and even in situations when we are dazzled, they might be not. Quite important: note also that the preference is axial - there are many cases when the dog actually looks southwards. There is no evidence for shift of the alignment axis during the day.

modzu 7y ago
that is.. a stretch. so they didnt actually look at sunlight hours they simply assumed the probability from the distribution of the data?? both hypotheses are plausible (sunlight vs magnetic fields) but this reads like data fitting rather than treating each possibility equally blind. where was it published?
nate_meurer 7y ago
Yes, I read the whole thing when it came out years ago. I remain thoroughly unconvinced. Back when this study came out, pop-sci magazines and websites reported it uncritically. But it was also a much less cynical time, before the reproducibility crisis really took hold. Aside from the blatant and unapologetic p-hacking, there are some other flaws of data gathering and analysis that make their conclusions dubious. For example, note that your first paragraph above seems to admit that the actual presence of direct sunlight was not recorded in the raw data. They only figure in a statistical inference based on average hours of sun in a locale. Rather than copy-pasting myself, here's a better critique from 2014 with good explanations of the study's problems: http://skeptvet.com/Blog/2014/01/do-dogs-line-themselves-up-with-the-earths-magnetic-field-to-poop/ http://skeptvet.com/Blog/2014/01/do-dogs-line-themselves-up-...
- blazespin 7y ago
  Maybe you should have started with that, rather than anecdotal evidence. I agree as a case study of potential p-hacking, it's pretty illustrative. Not sure if it's failed p-hacking though. For example - High school students, but did make it into a journal .. Dogs excreted with the body aligned along the North–South axis, but when exposed to small bar magnets, significantly changed their directional positions. The study suggests that dogs are able to recognize MF. Additional value of this research is that the data were collected by local high school students, which required collaboration with teachers and their parents. We think that this idea has great potential and can be developed at a global scale and to become a citizen-science project involving other high school pupils and their families. https://www.sciencedirect.com/science/article/abs/pii/S1558787819300978?via%3Dihub https://www.sciencedirect.com/science/article/abs/pii/S15587... Dogs can be trained to find a bar magnet https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301327/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301327/ We excluded visual cues and used control trials with food treats to test for the role of olfaction in finding the magnet. While 13 out of 16 dogs detected the magnet significantly above chance level (53–73% success rate), none of the dogs managed to do so in finding the food treat (23–40% success rate). In a replication of the experiment under strictly blinded conditions five out of six dogs detected the magnet above chance level (53–63% success rate). These experiments support the existence of a magnetic sense in domestic dogs. Whether the sense enables dogs to perceive MFs as weak as the Earth’s MF, if they use it for orientation, and by which mechanism the fields are perceived remain open questions. So maybe there is some value in p-hacking, when taken with an appropriate grain of salt? The problem is science journalism and its readers often don't know how to do that.

modzu 7y ago

that is.. a stretch. so they didnt actually look at sunlight hours they simply assumed the probability from the distribution of the data?? both hypotheses are plausible (sunlight vs magnetic fields) but this reads like data fitting rather than treating each possibility equally blind. where was it published?

nate_meurer 7y ago

Yes, I read the whole thing when it came out years ago. I remain thoroughly unconvinced. Back when this study came out, pop-sci magazines and websites reported it uncritically. But it was also a much less cynical time, before the reproducibility crisis really took hold. Aside from the blatant and unapologetic p-hacking, there are some other flaws of data gathering and analysis that make their conclusions dubious. For example, note that your first paragraph above seems to admit that the actual presence of direct sunlight was not recorded in the raw data. They only figure in a statistical inference based on average hours of sun in a locale. Rather than copy-pasting myself, here's a better critique from 2014 with good explanations of the study's problems: http://skeptvet.com/Blog/2014/01/do-dogs-line-themselves-up-with-the-earths-magnetic-field-to-poop/ http://skeptvet.com/Blog/2014/01/do-dogs-line-themselves-up-...

blazespin 7y ago
Maybe you should have started with that, rather than anecdotal evidence. I agree as a case study of potential p-hacking, it's pretty illustrative. Not sure if it's failed p-hacking though. For example - High school students, but did make it into a journal .. Dogs excreted with the body aligned along the North–South axis, but when exposed to small bar magnets, significantly changed their directional positions. The study suggests that dogs are able to recognize MF. Additional value of this research is that the data were collected by local high school students, which required collaboration with teachers and their parents. We think that this idea has great potential and can be developed at a global scale and to become a citizen-science project involving other high school pupils and their families. https://www.sciencedirect.com/science/article/abs/pii/S1558787819300978?via%3Dihub https://www.sciencedirect.com/science/article/abs/pii/S15587... Dogs can be trained to find a bar magnet https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301327/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301327/ We excluded visual cues and used control trials with food treats to test for the role of olfaction in finding the magnet. While 13 out of 16 dogs detected the magnet significantly above chance level (53–73% success rate), none of the dogs managed to do so in finding the food treat (23–40% success rate). In a replication of the experiment under strictly blinded conditions five out of six dogs detected the magnet above chance level (53–63% success rate). These experiments support the existence of a magnetic sense in domestic dogs. Whether the sense enables dogs to perceive MFs as weak as the Earth’s MF, if they use it for orientation, and by which mechanism the fields are perceived remain open questions. So maybe there is some value in p-hacking, when taken with an appropriate grain of salt? The problem is science journalism and its readers often don't know how to do that.