'Testing the Cultural Intelligence Hypothesis in Orangutans'

Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2016 Testing the Cultural Intelligence Hypothesis in Orangutans Forss, Sofia Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-132304 Dissertation Originally published at: Forss, Sofia. Testing the Cultural Intelligence Hypothesis in Orangutans. 2016, University ofZurich, Faculty of Science. Testing the Cultural Intelligence Hypothesis in Orangutans: Variation in Novelty Response, Exploration and Intelligence Dissertation zur Erlangung der naturwissenschaftlichen Doktorwürde (Dr. sc. nat.) vorgelegt der Matemathisch-naturwissenschaftlichen Fakultät der Universität Zürich von Sofia Forss aus Finnland Promotionskomitee Prof. Dr. Carolus van Schaik Dr. Judith Burkart Prof. Dr. Josep Call Prof. Dr. Christoph Zollikofer Zürich, 2016 Creativity is intelligence having fun - Albert Einstein “ ” Thesis summary Culture is a key element in human evolution and one of the driving forces to greater intelligence. The capacity to attend to and learn necessary skills provided by our socio-cultural environment has been highly selected for and is a fundamental component of human nature. Nevertheless culture is not unique to humans. Accumulating evidence for culture in non-human animals has altered the question toward how cultural processes link to cognition and the evolution of intelligence: i.e. cultural intelligence. The principle behind the Cultural Intelligence Hypothesis is that increased opportunities to learn skills socially during development improve an in . In species where such opportunities are abundant and frequent, it can dividual’sbe assumed intellectual that this makes abilities it possible for selection to act upon underlying cognitive mechanisms and consequently promote intelligence on an evolutionary time scale. The core of my work is to apply the Cultural Intelligence Hypotheses to one of our closest living relatives, the orangutans (Pongo spp) and thereby feature the shared evolutionary history of cultural processes shaping intelligence. Like in humans, culture in animals represents behavioral traditions founded on innovations, as the units of diversification. Thus, understanding the process of innovativeness is crucial in order to explain culture. It is commonly assumed that innovations arise in response to novelty, and therefore that innovative species are attracted to new things. Orangutan cultural diversity result from behavioral innovations, yet little is known about how orangutans respond to novelty. In my first study (chapter 2), I examined reactions toward novelty in wild orangutans through a set of field experiments. Results demonstrated strong conservatism, in form of passive avoidance of novelty. Although this outcome was expected based on previous experience with orangutans, it demonstrated that the intuitive link between innovativeness and a positive response to novelty does not hold for orangutans. I could show that they do not touch unfamiliar objects and thus are naturally not drawn to novelty and yet extensively explore familiar items within their habitats. These contradictive findings only make sense in the light of cultural intelligence: the pathway through which individuals integrate novel innovations is not by exploration of novel items, but rather due to social learning, which may include individual exploration of familiar items. In order to investigate the environmental influences of captivity, the same novel items were then presented to zoo-housed orangutans. Beyond the risk-free existence of a captive habitat, orangutans brought up in zoos experience increased social contact with conspecifics and social contact also with human caretakers, which is lacking in their natural habitat. In contrast to their wild conspecifics, all zoo individuals took an instant interest in the novel objects. Inspired by the contrasting results on novelty response in captive and wild orangutans, I conducted an extensive review of the literature where I examine variation in neophobia in a broad comparative framework (chapter 3). In the review I predict that species with slow-paced life history, such as the great apes, benefit from conservativeness in their natural habitats, because they can rely mainly on social learning rather than independent exploration. Interestingly, in captivity, trust in humans as role models erodes their innate neophobia, and even makes them rather neophilic due to their strong exploration tendency. The innovation paradox can thus be understood by considering a species dependence on role models, i.e. social learning, which is critically supportive of the Cultural Intelligence Hypothesis. In my fourth chapter I examine the outcomes of a strong adaptation for social learning and focus on actually empirically testing the Cultural Intelligence Hypothesis. Since cultural species develop their skill set through social learning, selection on learning mechanisms must have been high. Consequently, species with systematically richer social environment may over time evolve to become more intelligent, reflected by larger brain size. To test this evolutionary perspective of the Cultural Intelligence Hypothesis was the primary goal of chapter 4. Over an evolutionary time scale, the two orangutan species, Pongo abelii and Pongo pygmaeus, have experienced different socio-ecological environments, reflected in higher social tolerance and greater sociability in Sumatran P. abelii. This in turn has favored transmission of skills resulting in larger skill pool and thus more frequent opportunities for social learning in Pongo abelii. In order to control for the variation in social- and ecological factors of the natural habitat, I performed a zoo study to compare cognitive abilities between the two Pongo species. The homogenous environments provided by zoos allowed me to detect any intrinsic differences between the two species. The findings illustrate the ultimate product of cultural intelligence and suggest a clear intrinsic difference in how the two Pongo species apply their learning ability, with Pongo abelii showing better problem solving skills. Not only did I find a species difference in cognitive performance but P.abelii also showed higher levels of inhibition and different styles of exploration. I conclude that this species difference in learning ability is consistent with a history of greater sociability and social tolerance in Pongo abelii. My last chapter returns to how a captive life influences cognitive abilities and focuses on causes to inter-individual variation of problem-solving abilities. In collaboration with my colleague Laura Damerius we measured novelty response, exploration and cognitive performance in a large sample of captive housed orangutans from both zoos and rehabilitation stations. Our sample consisted of individuals varying in rearing conditions and duration of human exposure, which both are predicted performance. To estimate variation in reactions to humans toamong strongly individuals alter an individual’swith different cognitive rearing backgrounds, which we expected to be at least partly responsible for the variation in cognitive performance, we developed human orientation indices (HOI- index). Our results revealed that none of the other factors, such as the time in captivity, zoo versus sanctuary housing, species, age or rearing conditions influenced cognitive performance in any way. Instead, the social element of human attentiveness, i.e. the outcome of the HOI- test, was the strongest predictor of explorative behaviors leading to higher cognitive performance. In favor of the Cultural Intelligence Hypothesis individuals that exhibit a high HOI exhibit a different attention structure and may have experienced a different nature of learning opportunities by attentiveness to humans. Thus, as humans become additional trusted role models for apes housed in captive environments their influence does not only wear down neophobia, as stated in chapter 2 and 3 but it also promotes creativity. Zusammenfassung Kultur ist ein wesentliches Element der menschlichen Evolution und ein einflussreicher Antrieb für die Entstehung höherer Intelligenz. Die soziale Kompetenz, notwendige Fähigkeiten von unserem sozio-kulturellen Umfeld zu lernen, ist eine fundamentale Komponente des menschlichen Charakters und ein Produkt der natürlichen Auslese. Dennoch ist Kultur kein Alleinstellungmerkmal des Menschen, wie die zunehmende Zahl von Nachweisen von Kultur bei anderen Tieren zeigt. Die entscheidende Frage ist, wie kulturelle Prozesse mit Kognition und der Evolution von Intelligenz verbunden sind, ob es also eine sogenannte kulturelle Intelligenz gibt. Das Prinzip hinter der Kulturellen Intelligenzhypothese ist, dass ein Individuum über umso bessere intellektuelle Fähigkeiten verfügt, je mehr Gelegenheit zu sozialem Lernen es im Laufe seiner Entwicklung erhält. Bei Arten, mit stark ausgeprägtem sozialen Lernen führt die natürliche Auslese der involvierten kognitiven Mechanismen im Laufe der Evolution zur Förderung der Intelligenz. Das primäre Ziel meiner Doktorarbeit ist es, die Kulturelle Intelligenzhypothese anhand eines unserer nächsten Verwandten, den Orang-Utans (Pongo spp), zu prüfen und die Rolle der kulturellen Prozesse in unserer gemeinsamen Evolutionsgeschichte zu untersuchen. Genau wie beim Menschen besteht Kultur bei den Tieren aus verschiedenen Verhaltenstraditionen, die auf Innovationen aufgebaut sind. Um Kultur

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