I was at the meetings of the American Association of Physical Anthropologists last week in Calgary. Great to see so many friends, and to meet many new people – I especially loved meeting some students who had recently been following the blog!
One day I was talking with a group of people, realizing just how much the subject matter of paleoanthropology has transformed during the last five years. For one thing, it seemed like there were a lot of papers about Australopithecus sediba, a species that didn’t exist five years ago! But we also noticed an increase in the number of papers that seemed to engage with Australopithecus africanus over previous years. By contrast, it seemed to us that A. afarensis faded in importance compared to previous years. Maybe it was just the way it seemed – especially with only a single podium session devoted to early hominins.
Anyway, after I got home, I decided to do a little counting through the abstracts of previous years. I looked at the abstract volume from 2008, and also from 2002 – six years and twelve years ago, compared to this year. I did a count of the number of separate abstracts that mention each species name in human evolution – and then also for “Neandertals” as a group. The abstracts include both podium talks and posters, and across the last twelve years the total number of presentations has increased, largely by adding more posters. I didn’t do any kind of content analysis – some abstracts mention a lot of species names because of the nature of the comparisons they have carried out, while some are especially devoted to the study of one of these species.
Well, as you might expect there are a lot more talks and posters about Neandertals than the other groups. There are just many more areas of biology that people can examine interesting questions about this group, including genetics, which has fueled a continued increase in numbers. “Neandertals” here includes abstracts that mention the word “Neanderthal”, “Neandertal”, and “Homo neanderthalensis”. What may be interesting is that the “Neandertal” spelling had actually declined substantially in the 2008 meetings, but has more than rebounded this year. “Homo neanderthalensis” as a variant has blipped upward from zero in 2002, although it still accounted for only 5 abstracts this year.
You can see that my initial impression about A. afarensis was wrong: There are just as many abstracts this year about A. afarensis as in past years. Likewise A. africanus has basically held steady across this time interval. I did not include it in the chart, but A. robustus (including mentions of Paranthropus robustus) also held strong with 8 abstracts this year. Homo erectus has fluctuated but remains consistently popular.
Immediately stunning is the incredible presence of A. sediba so soon after its discovery. It didn’t exist in 2008. This year it accounted for as many abstracts as A. afarensis. The open access policy to the Malapa hominins has contributed to this incredibly rapid growth in research. I’ll further point out that the numbers here are not counting the Paleoanthropology Society meetings, where a number of additional papers on A. sediba were presented – including by some notable critics of the original research. People can see the material, and they are doing productive work on the fossils as a result.
Note that the timeline of A. sediba from its 2010 description to the 2014 meetings is roughly the same as the time from the 2004 description of Homo floresiensis to the 2008 meetings. Yet the scientific research output on A. sediba this year was double that of the hobbits in 2008.
By contrast, the research on Homo habilis seems to have greatly declined. Only a single abstract mentioned the species this year – and that abstract was a phylogenetic study that mentioned a long list of other species as well. This trend seems a bit puzzling in comparison to the great interest in A. sediba, considering that the two are thematically linked as possible ancestors of later hominins. I wonder whether the difficulty of recent travel to Kenya may have contributed to researchers’ decisions to avoid this topic. The other species to show a strong decline in 2014 was another East African endemic, A. boisei, which went from 7 abstracts in 2002 and 2008 down to 2 abstracts this year.
The chart isn’t exhaustive – I omitted many names, like Ardipithecus, Sahelanthropus and Kenyanthropus that have only been represented in one or two papers a year. Even this year, five years after the publication of the monograph-length treatment of Ardipithecus ramidus in Science, only three abstracts mention the genus.
Is there a message in these comparisons?
Naturally the value of research topics will shift from year to year. I haven’t looked at last year, and it would probably be even more illuminating to look at a more detailed trend. You can see that the hobbits continue to attract a good degree of interest, even without anyone being able to include new observations on them!