Dogs tend to ignore suggestions from people who are lying, hinting that – unlike human infants and some non-human primates – they might recognise when a person is being deceptive.
“We thought dogs would behave like children under age 5 and apes, but now we speculate that perhaps dogs can understand when someone is being deceitful,” says Ludwig Huber at the University of Vienna. “Maybe they think, ‘This person has the same knowledge as me, and is nevertheless giving me the wrong [information].’ It’s possible they could see that as intentionally misleading, which is lying.”
Huber and his colleagues trained 260 dogs of various pure breeds to find hidden food in one of two covered bowls. The dogs learned to follow the suggestion of a person they had never met – the “communicator” – who would touch the food-filled bowl, glance at the dog, and say, “Look, this is very good!” Dogs appeared to trust this new person when they were reliably following the signal, Huber says.
Once that trust was established, the team had the dogs witness another person move the food from the first to the second bowl. The communicators were either in the room, and also witnessed the switch, or were briefly absent and so apparently unaware that the food had been switched. In either case, the communicators would later recommend the first bowl – which was now empty.
In previous versions of this experiment with children under age 5, Japanese macaques or chimpanzees rather than dogs, the participants reacted in particular ways. If a communicator had been absent during the food switch, it would appear that they could not know where the treat really was. As such, the children, chimps or macaques would typically ignore a communicator who gave honest – but misleading – advice on where the food was, says Huber.
However, if the communicator had been in the room and witnessed the switch, but still recommended the first (now empty) bowl, young children and non-human primates were actually much more likely to follow the communicator’s knowingly misleading suggestion to approach the empty container.
This may be because the children and non-human primates trusted the communicator over the evidence of their own eyes, says Huber.
The dogs in the new experiment, however, were not so trusting of lying communicators – much to the researchers’ surprise, Huber says. Half of the dogs would follow the communicator’s misleading advice if the communicator had not witnessed the food switch. But about two-thirds of dogs ignored a communicator who had witnessed the food switch and still recommended the now-empty bowl. These dogs simply went to the bowl filled with food instead. “They did not rely on the communicator anymore,” Huber says.
“This study reminds us that dogs are watching us closely, are picking up on our social signals, and are learning from us constantly even outside of formal training contexts,” says Monique Udell at Oregon State University, who was not involved in the study.
The fact that half the dogs trusted the communicator who seemed to have made an honest mistake could reveal a lot about how dogs process social information, Udell adds. “There is both genetic and behavioural evidence that dogs are hypersocial, meaning that many dogs have a difficult time ignoring social cues even when another solution might be more advantageous,” she says. “This is a really striking example of just how often this may occur.”
Journal reference: Proceedings of the Royal Society B, DOI: 10.1098/rspb.2021.0906
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