Re:Paper is a pet project where I get to read interesting papers from the past and share my thoughts/impressions. It's not too dissimilar to book reviews, except for papers. Or paper-like things (a talk that gets published, an essay from an academic, etc.)
For 003, I have Animal Cultures: How We've Only Seen the Tip of the Iceberg from Caroline Schuppli and Carel van Schaik.
When Jane Goodall saw the chimps stripping leaves off a twig and use it to fish for ants from holes in the earth, she wrote to her mentor, who promptly said of this event, "Now we must redefine tool, redefine man or accept chimpanzees are humans."
At the time, we were of the opinion that what differentiated humans from the rest of the animal kingdom was tool-use.
A story not too dissimilar is what we have with culture. Our old definitions of culture have been famously anthropocentric. Schuppli tells us of the most prevalent idea of culture from centuries ago:
The oldest explicit definition by a cultural anthropologist regards culture as 'that complex whole which includes knowledge, beliefs, arts, morals, law, custom, and any other capabilities and habits acquired by man as a member of society'. This human-oriented definition stresses that virtually everything we do, know or believe, as well as our institutions and technology, are a product of social learning and thus cultural.
"Social learning", it turns out, is not exclusive to humans. The debate about whether social learning itself is just a genetic disposition or an ecological happenstance or a combination of both that feedback into each other is the thing of spice all the way from Wilson to Laland to Richerson/Boyd.
Schuppli says:
In order to examine how human culture arose, biologists adapted this definition to non-human animals by describing culture as 'all behaviors and knowledge that are acquired and passed on within and between generations through social learning' (Boyd and Richerson, 1985). Hereafter, we refer to this as the minimal definition of culture.
...some have argued that culture must be more than the product of social learning.
In short, all definitions agree that skills and knowledge that are learned through a form of social learning are the quintessence of culture, irrespective of the actual social learning mechanism used. The more demanding definitions appear to reflect an attempt to distinguish the cultures of different taxa, especially humans from animals, although many habits we naturally call culture in humans are neither normative nor complex or diverse.
Schuppli's primary argument is that our definition of culture, even when pulled away from its inherent anthropocentrism, is about high-brow stuff like art, civilization, morality, religion and such but in fact, the simplest of subsistence skills like building a rudimentary nest, or foraging patterns is socially-learned and must be considered "culture".
Cultural repertoires are mainly composed of basic, low-complexity subsistence skills, most of which show clear ecological correlates (e.g. knowledge of diet composition and processing techniques).
For example, when deprived of the "social" component of learning, young orangutans couldn't really learn to build nests:
... it takes young orangutans years of close observation and subsequent practice before they can build nests good enough to spend the night in, and socially deprived young apes will never be able to do so.
So if we define culture as something we learn socially, then it's not just high-brow stuff; it can be as simple as survival skills.
Schuppli (and van Schaik) now turn their attention to another ongoing debate in the field: how do we measure animal culture? How do we differentiate between what's a direct result of Darwinian/Wilsonian genetic disposition or ecological constraints and what's something that a group specifically picked up and propagated through social learning?
Some folks came up with a way to find that out. It's called the Method of Exclusion (MoE).
Take two groups of orangutans. If one group shows a specific behavior and another group does not have that, and you can show that the behavior is not of genetic or ecological origin/causality, then bingo, you've got animal culture.
Folks like Laland are big proponents of MoE. van Schaik (the other author on this paper) has criticized that method.
That criticism finds a neat summary in this paper:
... social learning does not necessarily result in between-group heterogeneity. Identical ecological conditions are likely to bring about the same behavioral innovations in separate social units. Cultural transmission driven by social learning will thus inevitably produce similarities in behavioral repertoires between them, just as evolution driven by natural selection will often come up with the same genetic adaptations in similar environments. Whereas the latter is a widely acknowledged phenomenon, namely convergent evolution, the possibility of convergent culture is not yet widely acknowledged.
That is, two groups of orangutans could come up with similar-looking culture repertoires due to various factors.
Then:
because the MoE excludes the majority of cultural variation with ecological components, it is heavily biased in the kinds of cultural variation it captures. Whereas it detects disproportionately more behaviors of the social domain and complex dietary inventions such as tool use, it underestimates culturally transmitted basic subsistence skills. However, it is highly unlikely that the mechanisms of social learning are exclusively deployed for the acquisition of complex innovations; routine subsistence skills are almost certainly acquired in the same way.
That is, culture is not necessarily stuff of complex, sophisticated things but should also be just about basic subsistence skills.
And my favorite:
the number of cultural variants detected by the MoE is highly dependent on the number of populations we compare. Whereas a behavior X may well be shared between populations A and B, it may not be shared with population C. If we compare only populations A and B, behavior X will not be considered to be cultural, because it is found in all of the populations compared. If we then add population C to this comparison, behavior X will suddenly count as cultural because it is not universally shared among all compared populations. This inevitably leads to an underestimation of cultural repertoires.
Just plain ol' misspecification.
The Method of Exclusion is a comparative measure. What if we relaxed the definition of culture to one that is "socially-learned skills"? That allows us to study animal cultures without having to compare them to other groups. I think this is a simple but elegant rethink and one that matches how we think about humans too. Culture is part of human groups even in the absence of other groups and comparison to other groups.
Schuppli and van Schaik then go on to describe how, through their simplified, "minimal" definition of culture, one could go about measuring animal culture:
We propose to first identify and validate indicators of forms of social learning as actual means of social learning in a given species and then count the behaviors for which we can document that individuals deploy these indicators during skill acquisition. We call this procedure the method of counting socially learned skills (SLS).
One stand-out example from the paper is young orangutans in Sumatra and Borneo peering at adults and then practicing (copying) skills:
Recently, we studied peering behavior (i.e. attentive and sustained close-range watching of the activities of a conspecific) in immature orangutans.
The fun bit is that as a young orangutan grows up, the number of times they peer at others goes down:
By extrapolating cumulative peering counts based on known peering rates at different ages, we found that, over the course of their lives, Sumatran and Bornean orangutans (Pongo abelii and Pongo pygmaeus wurmbi) at the Suaq and Tuanan research sites peer around 38,000 and 9000 times. Individual's rates of peering are reduced to a minimum as adulthood is reached, at age 15.
We found strong evidence that peering by immatures is an expression of socially induced learning, since it was followed by selective practice, decreased with growing competence of the peerer and was more and more directed at less familiar role models with increasing age of the immature peerers.
The authors then go on to demonstrate that the difference in indicators between MoE and the SLS (socially-learned skills) method is enormous. (Hence the tip of the iceberg).
The MoE produces a biased sample of highly complex and conspicuous behaviors and dismisses a vast array of socially learned behaviors that covary with ecological factors. By counting socially learned skills, however, we are beginning to get to know the base of this iceberg. Cultural repertoires are mainly composed of basic, low-complexity subsistence skills, most of which show clear ecological correlates (e.g. knowledge of diet composition and processing techniques).
And revisiting the coevolution bit:
At the same time, a systematic reliance on social learning under similar ecological conditions may very well lead to many universal cultural behavior patterns across populations. The most striking example in the orangutans for this is nest building: even though it is an orangutan universal, it takes young orangutans years of close observation and subsequent practice before they can build nests good enough to spend the night in, and socially deprived young apes will never be able to do so. The basic construction of nests (a rim made of intertwined long branches) is highly comparable across different orangutan populations, presumably because it is the most latent solution to the problem.
A slightly tangential but relevant bit of history here for when it feels like culture couldn't be just about subsistence.
One of my favorite pieces of writing is Tanner Greer's Tradition is smarter than you are.
Tanner recounts a story told by Joseph Henrich, a "cross-cultural" psychologist:
Henrich advances the argument that brain-power alone is not enough to explain why humans are such a successful species. Humans, he argues, are not nearly as intelligent as we think they are. Remove them from the culture and environment they have learned to operate in and they fail quickly.
In the Colombian Amazon, for example, indigenous Tukanoans use a multistep, multiday processing technique that involves scraping, grating, and finally washing the roots in order to separate the fiber, starch, and liquid. Once separated, the liquid is boiled into a beverage, but the fiber and starch must then sit for two more days, when they can then be baked and eaten.
At the beginning of the seventeenth century, the Portuguese transported manioc from South America to West Africa for the first time. They did not, however, transport the age-old indigenous processing protocols or the underlying commitment to using those techniques. Because it is easy to plant and provides high yields in infertile or drought-prone areas, manioc spread rapidly across Africa and became a staple food for many populations. The processing techniques, however, were not readily or consistently regenerated. Even after hundreds of years, chronic cyanide poisoning remains a serious health problem in Africa.
The brain-power has a neat connection back to our paper here. Schuppli writes why it may not be a precondition to have a big brain in order to have a culture of one's own:
Since social learning can be very simple, culture does not require a large brain and it is therefore unlikely to be a hallmark of cognitive complexity...
But with a small caveat:
... the efficiency of cultural transmission may also favor the evolution of greater investment in brains.
Or in other words, it helps to have a big brain to spread culture across generations and geography efficiently — elephants, whales, great apes (including us) — but that does not mean other, smaller species do not have culture.
We've barely scraped the surface and only seen the tip of the iceberg.