Once adaptive – now annoying. Nuisance barks revisited
According to an illustrated encyclopedia for children, the dog is “an animal with fur that wags its tail and barks”. It is hard to debate the truth behind this wisdom (although naked dogs represent a problem), however dog barking is widely considered as one of the most unpleasant feature of man’s best friend. But why people become so annoyed when they hear the barking of dogs (especially the neighbor’s dog). And is this a uniform response or are there people who are especially prone to the effect of nuisance barks? These were the main questions of a fresh study done by researchers at the Department of Ethology, and recently published in Bioacoustics (Jégh-Czinege, N., Faragó, T., & Pongrácz, P. (2019). A bark of its own kind–the acoustics of ‘annoying’dog barks suggests a specific attention-evoking effect for humans. Bioacoustics, 1-16, https://doi.org/10.1080/09524622.2019.1576147)
The study involved more than 150 participants who had to listen and evaluate several dog bark samples. Subjects scored the nuisance effect of each bark, plus additionally they also rated how angry, happy and scared the dogs sounded on the bark recordings. Researchers tested three age groups (children of 10-11 years of age; young adults 18-35 years; older adults 50-70 years). In each age cohort there were people from three living environments: village, suburban and inner city inhabitants. The responses (annoyance and dog-emotion scores) were analyzed by comparing the scores between age cohorts and living environment types separately.
Rather surprisingly, the place where the participants lived did not have an effect on the annoyance scores – in other words it is not true that (for example) people living at the countryside would be more tolerant towards dog barking than city folk. Contrary to this, age of the participants had a strong association with the nuisance scores. Young adults were more annoyed by the barks than the children and the older adults. This effect was the strongest when the playbacks contained high pitched barks. These results are in good agreement with the theory that for people the baby cry-like sounds are the hardest to ignore. High-pitched barks fall close acoustically to baby cries, and young adults represent the age group that is biologically the closest to its child-raising function. Interestingly, the barks that have been considered as ‘most annoying’, had a unique acoustic setup. They were high pitched and harsh (low tonality). This type was different from those barks that people consider as ‘angriest’, or ‘most fearful’. This means that annoying barks are not simply aggressive and/or fearful sounds, but dogs have a specific type of barking that beyond conveying their inner state, can be characterized by an especially high attention eliciting effect for humans. One can hypothesize that this type of dog bark has been evolving for its adaptivity as an alarm signal in dog-human communication. The fact that nowadays it elicits mostly annoyance from people could be the by-product of the constantly growing number and density of co-habiting humans and dogs in the society.