The following article was kindly provided by Dr Marc Wilson and the team that has undertaken a research project entitled "Is pet ownership associated with better health and wellbeing?" It was published in the NZ Listener magazine as a summary of what their research project had found. The full peer-reviewed manuscript will be shared when it is published.
Our boy went from looking up rabbit care to adopting a house rabbit from the SPCA in about two weeks. By ‘house’ I mean my house. And we already have a dog, Banjo, because he really wanted a pet and we deluded ourselves, as do many parents, that it would be good for him. Teach him responsibility, give him a reason to go for walks, etc, etc.
One of the widely-held beliefs is that pets are good for wellbeing. There is a good amount of research out there to suggest that exposure to pets can be particularly good for some groups of people. For example, many trials that have involved taking cats and dogs into retirement homes show pronounced impacts on happiness, at least until the trial ends and the animals stop coming.
So surely having pets in general is good for us?
In 2021, a team of local researchers led by Dr. Gloria Fraser set out to test this, using data from the large scale New Zealand Attitudes and Values Study. The NZAVS is a big, nationally representative, longitudinal survey study that has become something of a world-leading machine for research.
The seventh wav of the NZAVS, collected over 2015/2016 asked people whether they owned any pets and, if they said yes, what kind(s) and how many. Just over 13,000 people answered the question, as well as a bunch of other personality and wellbeing-related questions.
First, Gloria had to classify all 13,000 people into groups such as ‘cats only’, ‘small mammal’ (including rats, mice, rabbits and chinchillas) or ‘no pets, which included mischievous responses (e.g., “1 husband,” “4 children,” and “Wife/Ex.”). About four in ten participants had no pets at all, and the most common pets were cats (about a third). Couples, and parents, were most likely to report having a pet.
The statistical take-home was that there were few, and generally weak, associations between psychological variables and pet ownership. People with dogs and farm animals reported a greater sense of community (cat owners reported less) and owning a pet of almost any kind meant participants were more likely to say they had a history of depression.
So does this mean having pets makes us depressed? Because this research was correlational, it could also be that people who feel lonely or sad are more likely to get a pet.
Enter our just-completed longitudinal follow-up, based on asking NZAVS participants about their pets in 2019 and 2020, and supported by a grant from the Healthy Pets charitable organisation. Longitudinal survey research allows us to use fancy statistical techniques to assess for ‘causal inference’ – whether wellbeing predicts future pet ownership, or vice versa. Specifically, ‘doubly robust Targeted Maximum Likelihood Estimation coupled with machine learning’ or, as I prefer to think about it, magic!
And the answer is… there appears to be no causal relationship between cat and/or dog ownership and mental distress, and the only reliable effects of dog and cat ownership are that cat owners say they get slightly less sleep, and dog owners say they get slightly more exercise. So, on the face of it, the common wisdom doesn’t seem to hold up in terms of causation.
Which isn’t the same as saying that pets don’t make people happier and healthier – what we don’t know is what non-pet owners might fill their non-pet time up with. Maybe they go to the movies more, or play more sport? In which case, it might be that pets are still good for people who don’t go to the movies or play sport.
Unfortunately what we don’t know is whether someone who says they had no pets in 2015 or 2019 had a pet at some point in between. Or if someone who said yes to the pet question all three years had the same pet. As usual, more research is necessary. For now, keep deluding yourself that you pet makes you healthier.