At a party some time ago, I got talking to a biology graduate friend about comparative psychology, as a geek tends to do at social occasions.
Comparative psychology is the study of animal behaviour and mental processing across different species. By doing this, it gives us clues to the function, benefit and development of a particular behaviour. Understanding the similarities and differences amongst different animals in this way can shed light on evolutionary relationships.
The topic came up because our friends were revelling in how cute baby animals are. If you don’t believe me, just look at these cherry-picked examples:
Baby fur seal
What’s striking is how wildly different baby animals can provoke the same “aaah” reflex. Baby primates and baby birds, separated from each other and from us by millions of years of evolution, can elicit the same cooing reaction. And size doesn’t seem to matter − a 100kg baby elephant can bring as much infatuation as a 5kg baby seal.
In other words, there’s something about being a baby, and not just a miniature version of an adult.
This immediately reminded me of an image drawn by Nobel prize-winning animal behaviourist, Konrad Lorenz. It shows how juvenile proportions are conserved across different animal groups, and goes someway to explain why we react to many baby animals as we do.
From Studies in Animal and Human Behavior, vol. II, by Konrad Lorenz, 1971. Methuen & Co. Ltd.
I think I first saw this image in a book by renowned evolutionary biology, Steven Jay Gould*. He also included it in a wonderful essay called Homage to Mickey Mouse. In this article, Gould explains that over time, to chime with his softening of character, Mickey’s appearance became increasingly juvenile.
A large head relative to body, short legs and feet, bulbous cranium and big eyes, as seen in a latter-day Mickey, look like the hallmarks of a juvenile. And Mickey travelled this path to juvenility in reverse − a phenomenon known as ‘neoteny‘.
An illustration’s fine, but to truly demonstrate this scientifically, Gould actually measured the relative changes in Mickey’s physical attributes and plotted the results on a graph. The result, as was Gould’s wont, is an engaging fusion of science and creative writing − do read it. (On reading, I did wonder whether Mickey’s appearance was altered to match a desired change in character, or the other way round.)
The key to all this is that the proportions of a baby’s face, as compared to an adult, are similar across many different animals. This set of features triggers what Lorenz described as an ‘innate releasing mechanism’ − an automatic and consistent reaction to an important behavioural cue. It makes sense that a hard-wired mechanism has evolved to trigger an immediate sense of attachment when confronted with a baby’s face − it will promote parental care, which has clear evolutionary advantages.
But that same hard-wired mechanism also appears to fire when we see similar baby-ish proportions in other animals. It’s an inappropriate response in an evolutionary sense, but it’s better to be harmlessly fooled by a baby bird than to not feel instinctively drawn to our own baby.
What’s fascinating is that, in some cases at least, these ‘releasers’ are reduced to very specific features. A classic example was demonstrated by Lorenz’s Nobel prize-winning collaborator, Niko Tinbergen, using three-spined sticklebacks. A male stickleback will attack another male, as identified by a red belly, but will also attack any object with a red spot − fish-shaped or otherwise. A stickleback-shaped object without a red belly is suitably ignored. Like a red rag to a stickleback, it’s better to be safe than sorry.
Babies do something similar in reaction to stylised smiley faces − a circle for a head, two dots for eyes, and a curved line for a mouth is enough to grab a baby’s attention. This stays with us into adulthood and is, for better or worse, the reason why emoticons are so enduring. So, similar to a stickleback reacting solely to a red spot, it seems it’s not a whole baby’s face we respond to, just a certain set of features.
Yes, your baby’s cute because of this graph:
“At an early stage in his evolution, Mickey had a smaller head, cranial vault, and eyes. He evolved toward the characteristics of his young nephew Morty (connected to Mickey by a dotted line).” By Steven Jay Gould
* I should dedicate this post to the late, great Derek Yalden, who taught me zoology at The University of Manchester and told me to read The Panda’s Thumb.
(As an addendum: none of this makes animals we find cute any more ‘worthwhile’ than “ugly” animals. Check out the recent campaign by the “Ugly Animal Preservation Society“.)