Consistent constellations across cultures

When you look up at the stars in the sky, what do you see? You may group certain stars into constellations, or asterisms, terms used to describe groups of stars that we like to view as related in some way. Humans have been doing this since time immemorial, placing significance on certain asterisms to tell stories and feel connected to each other and the universe. Now, a new study by Charles Kemp and a team of researchers from The University of Melbourne in Australia has been looking at the striking way in which cultures from throughout history have developed similar groupings of stars, and what this can tell us about how our brains interpret what our eyes are seeing, as James Tytko found out...

James - The night sky is a mystery which connects us all. The great cosmic questions of why and how are defining characteristics of what makes us human, and nothing brings these questions to the forefront of our minds as universally as simply staring directly up on a clear night.

Charles - Of course, people in different parts of the world see different parts of the night sky. People in the Northern hemisphere and Southern hemisphere have have different experiences, but still, it's a very important thing that's seen all around the world and it plays such an important role in culture as well.

James - Charles Kemp and a team of scientists from Melbourne have been trying to show that the shared experience of star gazing actually runs a lot deeper than we think.

Charles - We looked at a total of 27 different cultures drawn from all around the world, including cultures from Europe, Asia, North America, South America, some from Oceania and Australia as well.

James - Their work amalgamates the groupings of stars from astronomers all over the world in a bid to understand more about the way our brains interpret visual stimuli.

Charles - Maybe not surprisingly, it's rare to find an anthropologist who is expert in astronomy as well, and so is able to align what the local people are saying with the star names and accepted groupings that a Western astronomer would know. And so, because of this, there are a few really impressive anthropologists/astronomers who've had a background in both of those areas. The contributions of those people are incredibly important to the sorts of analyses across cultures that we were trying to do in our work.

James - And what were the broad conclusions you drew from this comparison?

Charles - I suppose the number one conclusion was that we think perceptual factors play a bigger role in shaping constellations across cultures than previously realised. Previous researchers would have agreed that there's a small handful of constellations that are near universal: these would include things like the Big Dipper and the Pleiadies, and so on. But, normally, when scholars talk about this, there's a list of usual suspects that includes maybe four or five groupings, but no others. But if you think about it, if there are these groupings that are near universal across cultures, and there are groupings that are one off, there's probably going to be some kind of gradient in between those two extremes, and there just hasn't been the data before to ask, for example, "So not universal by any means, but if they're appearing in half of the constellations across cultures, well, there's a striking regularity there." People all around the globe are working with essentially the same visual system and there are certain groupings that just jump out. It's well known from more than a century of research now, in visual perception, that factors like brightness, proximity and symmetry affect the patterns that people are able to see when you give them visual displays.

James - Through their work, Charles and his team are advancing the Gestalt theories of perception - Gestalt translating from German as 'pattern' or 'configuration'. Appearing in the early 20th century, they were the people who first developed the idea that characteristics such as brightness, proximity and distance between objects were responsible for how we view individual elements and grouped them together into a hole.

Charles - In fact, some of them informally mentioned constellations, star groupings, as examples of exactly the sort of grouping that they were interested in. As far as I know, nobody ever followed that up experimentally. There are experiments where, in the lab, people are presented with random dot patterns and what's interesting is to see how those patterns get organised into groups, but no one has ever really tried to use stimuli that look a bit more like actual stars and, for example, vary in brightness.

James - I wonder if we could zoom in on some striking similarities, maybe, between two very disparate sets of astronomers. Disparate by way of age or by distance. Examples that really leap out as surprising that people have connected together.

Charles - Well, maybe just one example that comes to mind: in the Western tradition, if you look at the accepted official 88 constellations, there's Corona Astralis and Corona Borealis, and both of them are groupings of stars that fall along the arch of a circle - kind of these smooth curves. They're both known as crowns or wreaths; I think maybe in the Greek tradition wreaths would be just as accurate a description. One of the cultures in our dataset, the people of the Marshall Islands, identify the same two constellations pretty much. Not only that, they refer to them as wreaths as well. So, in their culture, I think the relevant wreaths are wreaths made out of flowers. To me, that's a striking convergence. People have not only identified the same groupings across these two cultures, but they've interpreted them in the same way.