In a study conducted with the Scottish Society for the Prevention of Cruelty to Animals, researchers at the University of Glasgow played six-hour Spotify playlists from five genres of music to shelter dogs. On one day, the dogs heard classical; on others they grooved to soft rock, reggae, pop and Motown. The researchers recorded the dogs’ heart rate variability, their cortisol levels and behaviors like barking and lying down — all measures of stress levels — as they listened to the tunes, as well as on days when no music was played.
I thought you might be interested in the article abstract:
Classical music has been shown to reduce stress in kennelled dogs; however, rapid habituation of dogs to this form of auditory enrichment has also been demonstrated. The current study investigated the physiological and behavioural response of kennelled dogs (n = 38) to medium-term (5 days) auditory enrichment with five different genres of music including Soft Rock, Motown, Pop, Reggae and Classical, to determine whether increasing the variety of auditory stimulation reduces the level of habituation to auditory enrichment. Dogs were found to spend significantly more time lying and significantly less time standing when music was played, regardless of genre. There was no observable effect of music on barking, however, dogs were significantly (z = 2.2, P < 0.05) more likely to bark following cessation of auditory enrichment. Heart Rate Variability (HRV) was significantly higher, indicative of decreased stress, when dogs were played Soft Rock and Reggae, with a lesser effect observed when Motown, Pop and Classical genres were played. Relative to the silent period prior to auditory enrichment, urinary cortisol:creatanine (UCCR) values were significantly higher during Soft Rock (t = 2.781, P < 0.01) and the second silent control period following auditory enrichment (t = 2.46, P < 0.05). Despite the mixed response to different genres, the physiological and behavioural changes observed remained constant over the 5d of enrichment suggesting that the effect of habituation may be reduced by increasing the variety of auditory enrichment provided.
I would be very interested in knowing the magnitude of the effect for different types of music (t scores and p values do not tell us the effect size, something could be statistically significant, but of such a small magnitude to have no practical importance). Unfortunately, I am not able to access the article itself.