Humans are unique in their ability to develop sophisticated language abilities. Language allows us to communicate with each other and live in complex societies. It is key to our advanced cognitive abilities and technological prowess.
Executive Functions
The development of executive functions occurs slowly over the course of childhood. As they get older, children get better at organizing their thoughts and controlling their behaviours and emotions. In fact, humans are the only known species to develop advanced executive functions, although other species like birds, primates and dogs have rudimentary executive functions similar to young children.Canine Behaviour
For humans, studying dogs offers the perfect opportunity to consider these questions. First, dogs possess rudimentary executive functions. These can be measured in a variety of ways, including asking owners about their dogs’ ability to control their behaviours, as well as behavioural tests designed to assess dogs’ control abilities.However, many dog language studies have been limited in scope, either examining the word-based responses of only one or a small sample of dogs, or the responses of multiple dogs but only to select words.
Communicating With Dogs
Research with human infants does provide a solution for systematically and reliably assessing word-based responding in large samples of dogs. Arguably the best and most widely used measure of early language abilities of infants is the MacArthur-Bates Communicative Development Inventories, a parent-report checklist of words responded to consistently. Remarkably, the number of words selected on the MacArthur-Bates Communicative Development Inventory predicts children’s language development years later.In 2015, I began a collaboration with psychologist Catherine Reeve, at the time a graduate student working on dogs’ scent detection abilities. Our goal was to develop a similar measure of vocabulary for use with dog owners that we could then use to examine links between language and executive functions.
We developed a list of 172 words organized in different categories (for example, toys, food, commands, outdoor places) and gave it to an online sample of 165 owners of family and professional dogs. We asked them to select words that their dogs responded to consistently.
What we don’t yet know is whether dogs who respond to more words also have better executive functions. We recently assessed 100 dogs on a behavioural measure of executive functions and had their owners identify words on our vocabulary checklist. We are now analysing the results.