Dog eye size influences pet-directed speech in women
What is it about?
We experimentally tested if changing eye size would change the way we use pet-directed speech (PDS) towards images of dogs. PDS is commonly used when speaking to our pets by using a higher and more varied pitch. Women spoke to the dogs with a 15% larger eye size with more exaggerated PDS, however this effect was no longer significant when eye size increased by 30%. We suggest that an 'uncanny valley' effect takes over and the too-large eye sizes instead become unpleasant to view. Women also rated dogs with bigger eyes as younger in comparison to dogs with smaller eyes. Men did not significantly change their voices when speaking to the dog images. Interestingly, eye size did not have a significant effect on cuteness ratings.
Why is it important?
Neoteny (the retention of juvenile features) can encourage infant- or pet-directed speech from a caregiver or an owner. Eye size is a prominent neotenic feature in adult animals and human infants. We demonstrated that dogs with bigger eyes were perceived as younger (by women) but were not rated as cuter than dogs with smaller eyes. This suggests that PDS is affected by perceived youthfulness instead of perceived cuteness.