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ABOUT ME
I am trained in biology (especially behavioural biology), psychology (especially comparative and developmental psychology), archaeology (especially cognitive archaeology and early stone tools) and philosophy (especially philosophy of science). I am habilitated in the first three of these fields.
Currently my work is based at the University of Tübingen (Germany) where I hold a permanent research group leader position ("Tools and Culture among Early Hominins") in the Working Group of Early Prehistory and Quaternary Ecology. In addition, I am an adjunct scientist at the Lester E. Fisher Center for the Study and Conservation of Apes (Chicago, USA).
ABOUT MY WORK
My main drive is the age-old "Big Question": what are humans? Progress has been made to answer this question across fields - though there is still much debate. Any complete answer will most likely be multifactorial. Indeed, my own past research included several different lines of inquiry into this qustion (e.g. regarding special types of cooperation). However, for many years I have focused on examining cultural factors.
Focusing is necessary for two main reasons. First, the scope of this Big Question is far too large for one research group alone. I therefore have to focus. Second, it is likely that some of the multiple factors that will eventually be found will be more important than others. Arguably, an initial "hunt" for these more important factors will be more useful to answer this Big Question.
My focus on the study of culture has this very reason at heart - namely, I consider cultural factors to be among the most important factors to explain what humans are. Here is why. Culture is about the transmission of information, and so at least culture holds potential for a new type of evolution - cultural evolution. Many before me have suggested that cultural evolution has been a major difference-maker in humans. I wholeheartedly agree. Yet, culture is not monolithic. There exist many different types of cultural transmission (under the umbrella term of "social learning"), which all lead to different types of culture. Where any of these types of cultures additionally evolve (not all do), these differences in culture types will even translate into different types of cultural evolution.
My approach is as follows. Empirically, many types of cultural evolution are restricted to humans, and neither are they restricted to humans' closest living relatives (the non-human apes (apes)). Such types of cultural evolution may hold little explanatory power for human evolution, specifically. Consider cultural evolution of location information. More precisely, cultural evolution of socially learned information of what I call "know-where". Imagine the social learning of the whereabouts of the best local watering-hole for a population of ungulates. For example, let us just say that this group initially sources water only from one watering location - e.g. the local lake. Over time, some individuals of this group may stumble upon a new watering source, e.g. they may detect a large puddle hidden behind a bush. Let us further imagine that this species of ungulates is capable of socially learning know-where and that this puddle is better in some aspect(s) than the lake (e.g. it contains no crocodiles). Both assumptions are realistic. Indeed, with regards to the social learning assumption, the ability to socially learn about know-where is empirically widespread in the animal kingdom. Ungulates can socially learn know-where. Taking all together, after initial detection of a better watering hole by one or few ungulates, the rest of the group may socially learn the whereabout of this new, better watering hole from the original discoverers. If so, this would be an example of cultural evolution (from bad to good watering holes). To be precise, it would be cultural evolution of know-where-to-drink. Notice however, that these ungulates would not have had to socially learn how to drink, or how to walk to the new watering hole etc.. Said more generally, even when there is a case of cultural evolution of one type of knowledge (here: know-where), this does not have entail that there is (or has to be) additional cultural evolution among other types of knowledge. This is important because the main (ongoing) debate surrounding animal culture research generally and ape research especially can be summarised as the question of whether they culturally evolve their know-how.
My focus is indeed on the cultural evolution of know-how. I study this in humans, apes and hominins. The reason is simply that culturally evolved know-how is special. This may not be obvious, but can easily be shown. Consider this. Many of the most prototypical things that human culture consists of (e.g. words and gestures inside languages) require cultural evolution of know-how. The same is true for much of human technology (and other domains). Indeed, absent widespread know-how copying skills in humans, you, the reader, would be without whatever device you are reading this text from, you would be without the ability to read at all, and you would also lack spoken or signed language. The same would be true for me, of course - as it would be for all humans. Absent cultural evolution of know-how our worlds would be very different indeed.
While I am ultimately interested in the distribution of the base underlying ability - know-how copying - in the entire animal kingdom, for now I focus on humans, apes, and humans' deep ancestors (so-called hominins). In this way, I seek answers to the qustion since when our lineage culturally evolved know-how. Yet, ultimately, I am interested in understanding the evolution of the cultural evolution of know-how in the human lineage. Why and how did we become a species dependent on culturally evolved know-how? In many ways, this is tackling the question when and why we became human.
A useful and widely used benchmark for this kind of questions contrasts levels of know-how that are principally reachable by invidviduals in the absence of know-how models ("latent know-how") with levels that require and necessitate know-how models ("supraindividual know-how"). Again, your curent eading device, your reading and language abilities all contain examples of the latter kind. They are all supraindividual in their know-how. There exist many more examples of this in human life. My lab recently estimated that human society has produced billions of supraindidivial know-hows. Daily, many more are added.
Bringing all of this together, one of the concrete questions that my research is currently in the process of answering is when in human evolution we see the first instances of supraindividual know-how. Again, an answer to this question will (in some way) answer the question when we became human. Once we will have produced a robust answer to the when-question we can meaningfully examine the why-question - by looking at the ecological and biological factors that acted at and before this time. Answering these questions (if we succeed, that is) will give us some answer as to why we became human.
Currently I estimate the first occurences of supraindividual know-how at between one million and five hundred thousand years ago. To derive at this tentative answer to the when-question, I have systematically searched, often using a triangulating approach.
First, I examined ape cultures for whether they contained supraindividual know-how and cultural evolution of know-how. Apes are our closest living relatives, and answers here promised to illuminate whether the first flickerings of supraindividual know-how will have likely preceded the split of the ape and the human lineage or whether it postceded it. Said in a different way: if all ape species today culturally evolved their know-how to supraindividual levels, then this type of cultural evolution would likely have a very deep prehistory. In that case, the last common ancestor of apes and humans would likely have shared in this type of culture. However, various outcomes showed: with a high likelihood, apes do not (or very rarel) share in this type of culture with humans.
First, apes either never, or very rarely, socially learn know-how at supraindividual levels from others. More precisely, apes in their natural state do not do so. The exception are human-trained apes, whose abilities are however human-driven and thus phylogenetically irrelevant. In their natural state, apes socially learn other types of information well (e.g. know-what and know-where), but their social learning of know-how does not reach beyond what they can principally achieve on their own accord. The social learning of know-how is naturally restricted to "latent know-how" in apes (either completely, or near completey - are the two remaining options). In short, the types of social learning (and the types of cultures associated with them) that apes do use are either unsuitable, too weak or too rare for them to produce and sustain human-like cultures that would consist of supraindividual know-how. Second, all, or nearly all, of the the types of know-how that apes show across their natural populations are clearly re-inventable by individual apes. This goes against the very definition of supraindividual know-how. To produce such know-how, the apes therefore also have no need for powerful abilties of social learning of know-how. The types of social learning that they are naturally capable of suffice to produce and maintain ape cultures.
In short, apes do not copy know-how and they do not need to. Ape cultures are real, but they are different from human culture. Ape cultures exist, yet, when it comes to the know-how contained in them, these cultures owe more to processes that are prinicipally similar to catalysation than to processes of information transmission. This is important, as this means that the know-how inside ape cultures is robbed of the main motor of evolution: ape know-how lacks cultural inheritance.
Given a relative absence in all contemporary apes, the key type of culture - cultural evolution of know-how - was unlikely present in the last common ancestor of apes and humans. That is, among apes at least, this type of culture must have evolved on the human lineage alone.
Once the ape culture picture became clear, I therefore turned my attention to the study of past cultures - to archaeology (this switch happened ca. 2010). Within archaeology, the earliest evidence for which we have sufficient amounts of examples are early stone tools. The earliest widely accepted stone tool category in the record is the so-called Oldowan (ca. 2.5 million years ago). The main find inside this Oldowan is the "flake" - a sharp piece of stone that was mechanically removed from a volume of stone in acts of (suspected) tool-making. It is widely believed that flakes were intended to be used as tools and that it was especially the resulting sharp stone edges that wwere sought after by their makers - so that these edges could act as "artificial teeth" tools. Regardless the reasons for their production, we pointed out that the specifics of flake production found in the record lack to-be-expected patterns of cultural evolution of know-how. Instead, for very long periods of time - hundreds of thousands of years - the underlying know-how is best described as having stayed static. Note that stasis is the opposite of an evolutionary pattern. Given this, we pointed out that the know-how underlying Oldowan flake production unlikely evolved culturally via know-how copying. We pointed out that the underlying know-how was likely latent at the time(s) - i.e. that this know-how would have stayed principly within reach of individuals (much like ape know-how today is latent). This is not to deny Oldowan culture at all - yet, it is denying that the patterns point specifically to cultural evolution of know-how.
Our latest studies additionally showed that modern humans do not require know-how models to reinvent Oldowan flake-making techniques. This finding is clear proof-of-principle that these know-hows are not in and by themselves evidence for supraindividual know-how. It is therefore no longer right to consider the mere presence of these techniques (as inferred by archaeological work) as self-evident indicators for the presence of know-how copying. In line with this, in our recent ape tests we also found instances where unacculturated, untrained and Oldowan-naive apes likewise spontaneously made Oldowan-like flakes. In one case, an ape even used Oldowan-like flakes as a tool.
All in all the Oldowan is therefore unlikely the origin of cumulative cultural know-how in our lineage. I am currently involved in systematically testing the subsequent stone tool technology - the so-called Acheulean. Here I focus on the early Acheulean (ca. from 1.7 million years ago). My lab has also published on the empirically observed stasis in the early Acheulean - which renders it unlikely that the early Acheulean was the orgin of human-like culture. We also ran some dedicated studies on the early Acheulean, which we are currently in the process of publishing.
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Other topics that my lab studies include potential physiological reasons for chimpanzee hunting behaviour (a behavioural ecological perspective on their hunting) the evolution of human-like cooperation (especially of reputation-based cooperation), underlying reasons for suspected cases of altruism in great apes and the evolution of self-medication, ritual and art.
Generally, my lab approaches these topics by studying non-human animals (mainly great apes), human adults and human children (also, sometimes, cross-culturally) with a diverse set of methodological approaches (theory and experiments, but also via modelling). We likewise study the archaeological literature, as a source of useable data. We combine our data with insights from developmental and comparative psychology, evolutionary and behavioural biology, cognitive and lithic archaeology, biological anthropology and philosophy, to produce and distill best explanations and theories.
Through broadening the scope of species examined, extending the findings into our evolutionary past and by developing additional triangulating research paradigms that can ideally also be applied non-linguistically, I aim to continue probing the origins of the cultural evolution of know-how in human ontogeny and phylogeny, as well as - eventually - the distribution of cumulative cultural know-how across the entire animal kingdom (e.g. some bird song).
External Links:
My blue sky account
[Note that Google Scholar is more up to date than ORCID etc below]
The website of the (finished) ERC Grant "STONECULT"
My research group's blog (note: this blog has infrequent entries)
Google Sites
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