Neil Evans, professor of integrative physiology at the University of Glasgow's Institute of Biodiversity, Animal Health and Comparative Medicine, said the researchers played reggae, soft rock, pop, Motown, and classical music for the dogs.
"Overall, the response to different genres was mixed, highlighting the possibility that, like humans, our canine friends have their own individual music preferences," Evans said. "That being said, reggae music and soft rock showed the highest positive changes in behavior."
Evans offered a possible explanation for why canines might prefer reggae and soft rock.
"There is some evidence from work in humans that suggests that the relaxing effects of music are related to aspects of tempo or repeated motifs that can be present in the music," he said. "Possibly the reggae and soft rock have that more overtly expressed."
The SPCA said its shelters in Glasgow and Edinburgh currently have the ability to pipe music directly into dogs' kennels, and the rest of the charity's facilities in Scotland will now be similarly outfitted.