Happy Father's Day, everyone!
I spent a lot of time today thinking back to why I started blogging in the first place, while I was at my parents house doing the other-than-science things that I love to do: playing with the dog, cooking, gardening. I realized that I've not done enough of that stuff lately.
I've only been seriously doing the blog thing (in the current format) since January, and I've now been here at Scienceblogs around two months, so it was time to reflect. The transition from Wordpress obscurity to Scienceblogs prominence happened relatively quickly for me, and I think it's a good idea to look back. Why did I start blogging in the first place? In no particular order: First, to amuse myself. Second, as a means of outreach and professional development. Third, to get a lot more practice writing about science in a clear and accessible manner. They teach you in grad school to write for the academic or scientific audience, but not for the public. And I want to eventually write books. So after spending today getting back to the real-life non-science non-bloggie things that I enjoy, I'm going to get back to some of the science-bloggie things that I enjoy. Like blogging on Mondays about pets. So here we go. And in honor of father's day, we're going to talk about nurturance.
Human infantile cuteness - large, rounded forehead, big eyes, small chin - these are the kinds of things that make people totally fawn over human babies. (Aside: when these juvenile features persist into adulthood, in any species, it is called neoteny.) When an individual possesses these features, we call it "cute," and we respond to that cuteness with a variety of behavioral responses. We engage in baby talk (or "motherese"), which is characterized by an increase in the voice's pitch. We make eye-contact with the baby. We get protective. We're lenient. Lots of research suggests that these behavioral responses indeed predictably occur. The interpretation is that the affective (i.e. emotional) response to those physical features promotes the care of infants, who are otherwise helpless. But what is the mechanism by which cuteness enhances the adult's drive to care for the baby? One possibility is that cuteness serves to strengthen the attachment relationship between infant and caregiver, and as a result, the caregiver has an increased desire to, well, care. But the cuteness may engender the "cuteness response" that facilitates caregiving itself. That these two hypotheses are different may not be obvious: the stimulus (input) and behavioral response (output) are the same, but the mechanism is different. The first option operates by strengthening emotional attachment between two individuals, and the result of that emotional attachment is nurturance. The second hypothesis is a more direct mechanism - that human adults are "wired" (though i really really hate using that term, because it oversimplifies the issue) to care for the infant upon seeing those physical features.
Several researchers at the University of Virginia reasoned that since caring for a small helpless child requires one to behave very carefully, infant cuteness might increase behavioral carefulness, and they ran two experiments to investigate this issue.
They started from the assumption that increased carefulness is more critical for fine-motor movements (like when trying to get a toy with The Claw) than for gross-motor movements (like climbing a tree). So they operationalized behavioral carefulness by using a fine-motor dexterity task. Typical standardized laboratory tasks measure manual dexterity based on the number of objects moved per second. But cuteness may not increase speed of fine-motor activity, only accuracy independent of time. The best brain surgeons in the world may not be speedy, but you better hope they're highly accurate. Right? So the researchers had to develop their own measure of manual fine-motor accuracy to measure accuracy as independent from speed.
That's right. They had their experiment participants play the game Operation. And you thought all those hours spent trying to get the funny bone out of the dude's arm without making his nose light up were wasted. Not only did they measure overall accuracy in removing the little plastic bones, but they also modified the tweezers so measure how strongly the participant was squeezing them, as a measure of physical gentleness.
But how did they invoke the cuteness response? Pictures of baby puppies and (evil) kitties! (I know, you were starting to wonder how this qualifies as monday pets). So before they played the game, they were shown a slideshow of photographs of real animals. Some of them were young (and therefore, "cute") and some were mature (and therefore, un-cute).
The first experiment was broken into three portions, and all the participants were college-aged women. First, the participant played Operation, and had one chance to remove each of the twelve body parts. The total number of body parts successfully removed was recorded, as well as grip strength from the modified tweezers. Then, they viewed a slideshow with three sections. The first and third sections contained photos of houses and were identical between conditions. The second section contained images of animals: puppies and kittens for the high cuteness condition, and adult dogs and cats for the low cuteness condition. All photos were previously rated for cuteness by different people in a pilot study. Additionally, while the participants were viewing the slideshow and playing Operation, heart rate and skin conductance, both measures of arousal, were measured. After the slideshow, they played Operation again.
So how did they do? Viewing pictures of the cute animals increased performance on the Operation game (when compared with baseline performance, prior to viewing the animals), though there were no changes in grip strength. Heart rate was higher during the viewing of animal pictures in the high cuteness condition, but there was no effect on skin conductance. Furthermore, the individuals in the high cuteness condition reported more intense subjective experiences of happiness, calmness, tenderness, amusement, and entertainment. Additional analyses indicated that these effects were truly due to cuteness, and not general interestingness of the photos.
The second experiment was essentially identical to the first, but new animal photos were used that were better equated on things like interestingness, to further indicate that the effects from experiment one were due to cuteness and not due to something correlated with cuteness (like general interest). Additionally, the second experiment included both men and women, to find out if the effects of cuteness on carefulness was specific to women. Aside from these changes, the experimental design was identical.
First, a set of analyses indicated that the two sets of photos (high- and low-cuteness) were much better matched for interest and subject emotional intensity than in the first experiment. The general findings were replicated: viewing the cute animals increased performance on the Operation game, but not grip strength. In this experiment, neither heart rate nor skin conductance showed significant changes between conditions. This suggests that the increased performance on the Operation task was not due to general physiological arousal, but due to the increased cuteness of the stimuli. There were no significant differences due to gender.
Taken together, this study indicates that viewing images of baby puppies and (evil) kitties increased performance on the Operation game, a task which demands highly precise fine-motor movements. The researchers argue:
This behavioral shift toward increased carefulness makes sense as an adaptation for caring for small children, and is consistent with the view that cuteness is a releaser of the human caregiving system.
What this means is that cuteness doesn't just cause us to care for cute babies or animals in a general sense, but has specific effects on behavioral carefulness.
I think this study is really interesting. It fits nicely within the embodied cognition literature - that affective states, or the way we feel and think, are limited and expressed by the body. The nurturing behavior that is elicited by cute babies and animals directly makes us more physically careful, such as in motor behavior. Also, recall that as a result of the domestication of silver foxes some of the morphological changes observed included changes in skull shape and size, favoring larger foreheads. Domesticated foxes, compared to controls, had floppy ears, curly tails, and so forth. These are all features associated with "cuteness" in animals. Indeed, it has often been observed that domesticated animals are neotenous, retaining many of their juvenile features into adulthood. For animals which are relatively helpless and dependent on human caregivers (as domesticated animals, such as dogs, tend to be), it make sense that neoteny would have emerged through the course of natural or artificial solution so that human caregivers would feel compelled to care for them. I wouldn't hazard a guess (at this point) in terms of the direction of causality, but that there is a relationship in the first place seems reasonable.
According to the researchers, this was the first study that attempted to ascertain the relationship between cuteness and carefulness, so that should be kept in mind. But I'm just not convinced that the game Operation is really the proper measurement for fine-motor precision. Those who played the game as children might have felt certain emotions related to nostalgia, excitement, nervousness, or joy, which might confound the results. To be fair, the results are convincing, but I might be more satisfied with a less culturally-bound measurement of fine-motor precision. Still, though, pretty cool study. Must have been fun for the participants and the grad students who ran the experiments. And science should be fun. Right?
Sherman, G., Haidt, J., & Coan, J. (2009). Viewing cute images increases behavioral carefulness. Emotion, 9 (2), 282-286. DOI: 10.1037/a0014904
One question though - why does it make sense that neoteny would emerge through artificial selection (you wrote "solution." Did you mean "selection"?) "so that human caregivers would feel compelled to care for [the animals]" when we know that neoteny emerges even if the only trait you select for is flight distance? You can't posit a selection-based explanation for the emergence of neoteny when it seems like neoteny is a free rider on other features....
Thanks for the Father's Day post! Was this the only one on SB? Ah well.
Glad they did the follow-up experiment with men; it's always interesting to see how things are the same and different. (It'd be perhaps interesting to see if the gender of the *images* somehow affects performance).
Other age ranges would be good to have too.
Indeed, science *should* be fun (although it is necessarily also not, since it involves Work ;)
@ Tim Martin: It may be that the traits that are selected for in a population (such as, for example, domestic dogs) are in fact caused by certain aspects of neoteny, or a slowed or slightly less complete process of maturation. For example, if you select dogs to be social and friendly, and not to be vicious hunters, it seems plausible to me that the most social and friendly dogs (the ones you would want to breed) would be those that were most puppy-like (or cub-like, if we assume that you're starting with a population of wild dogs.)
What I think would be a neat experiment is testing this effect with and without observers of each sex present. I bet people's reaction to cuteness could be greatly enhanced or reduced depending on the company that's around.
I think I see what the disconnect is here. I was under the impression that the link between "tameness" and neotenous features is still an open question. Presumably there are genes that influence both, possibly by regulating the maturation process itself, but I didn't consider that to be a foregone conclusion when I made my comment. However, if we allow the premise that neoteny and tameness are linked features, then it would make sense that selecting for either one would increase expression of both. This explains how humans could unconsciously select for neoteny in domestic animals, and how Belyaev could select for low flight distance in foxes and still end up with neotenous foxes in addition.
Terminological question: Does "neoteny" only refer to morphological features (and not behavioral)?
Neoteny has been used to describe the persistence of juvenile behavior in adulthood, but more accurately, it refers to physiology. Physiological processes can affect both morphology and behavior.
One example of neoteny that isn't morphological in humans is lactose tolerance. Most other animal species, by adulthood, lack the proper enzymes to break down lactose. Human adults generally continue to tolerate lactose into adulthood, so that's a neotenous feature.
Merely anecdote, but I observed these responses in an exaggerated manner while watching my 3 year old granddaughter relate to her baby sister.
First, her initial reaction of "oh, she's so CUTE!" Second, her tentative and extremely gentle touching and caressing. And third, the pitch of her voice when talking to the baby got almost unbearably high to adult ears.
Until reading this, I assumed she was merely imitating adults and responding to admonitions to be careful with the baby. And I still think that is a factor, but maybe not as much of one as I originally thought.
Also, I've noticed that when a group of children (say 10 or more) of various ages (say 6 mos to 6 yrs) are sharing a play space, the older ones tend to be both careful with and helpful to the crawlers and toddlers. I first noticed this at family reunions, but have found it to be true at places like the play areas in malls. I'd love to read about research that touches on that.
I have recently been giving some thought to the relationship of neoteny and oxytocin, especially in relation to dog owners. It would have been interesting to see whether levels of oxytocin increased when the participants were looking at the "cute" images. Could the effects of oxytocin account for better performance on these tasks?
Elizabeth, that study would definitely be interesting. My immediate response is to be skeptical, because oxytocin has been implicated in emotional attachment (e.g. the authors' first hypothesis, which was not the one supported by the evidence).
However, I've written about oxytocin in terms of the relationship between pet dog and owner (as opposed to dog and human more generally), here.
Ah, first time commenter, just wanted to say thanks for taking the time to blog. There are few places on the Internet where people aren't shouting and cursing all the time, and this is one of them.
I imagine a closely related reverse effect that shows up in the breeding of dogs: People breed them down to those horrid, helpless, "cute" neotenous forms because those forms stimulate the pleasurable nurturing effect.
Just as an aside, I consider the creation of pug dogs (for instance, but also all the other twisted, crippled little breeds) to be nightmarish cruelty.