Periodic Reporting for period 2 - ENGINE (Engineering Interdependence - A Window into the Evolution of the Human Mind)
Período documentado: 2023-04-01 hasta 2024-09-30
The question of how and why the human mind evolved is among the biggest questions ever asked. Major progress has been achieved in answering how we are different from other primates, in particular chimpanzees, our closest relatives: Human children don’t differ that much with regard to particular physical cognitive skills but the gap is fundamentally social.
These differences are most apparent in socio-cognitive contexts, such as Cooperation, Communication, and Culture – the so-called big-C contexts.
Intriguingly, what underlies performance in these big-C contexts in which humans excel is bio-behavioral synchronicity: the coordination of biological and behavioral signals between interacting partners. In short, we align, and tune in with our interaction partners all the time. This ranges from heart rate synchronization to hormonal and behavioral synchronization, and even to vocal alignment.
We thus know well that the gap between apes and humans is fundamentally social.
What we do not know, however, is why this gap emerged: Why was it exactly us, rather than any of the other great apes to evolve into such a hyper-social cognitive niche?
Several answers have been proposed, and some of the most influential ones stress interdependence as key factor. Compared to other apes, humans are much more interdependent: within foraging bands, for instance, fitnesses are intertwined. This is because we critically depend on each other, with regard to our subsistence of cooperative foraging with extensive food sharing, and also with regard to child rearing: we are essentially cooperative breeders and hunters. One influential hypothesis argues this explains why our minds have evolved to be so fundamentally prosocial. The problem is that these ideas and hypotheses are reconstructions, and at best supported by correlative evidence.
The goal of ENGINE is to go beyond correlation, and experimentally investigate the consequences of increased interdependence, relying on plastic responses (“in real time”) to an increased or reduced need to cooperate. Thus, we experimentally manipulate interdependence in a colony of marmoset monkeys, to be able to assess the consequences in terms of synchronicity at various levels (hormonal, behavioral, acoustic) as well as the performance in big-C tasks.
We chose marmosets because they are renowned for their excellent socio-cognitive abilities and cooperativeness, which are necessary preconditions to make the interdependence treatment possible at all. Like humans, they cooperate extensively, in particular when rearing offspring. Furthermore like humans, they tune in with each other, and synchronize at the hormonal, behavioral, and even vocal level.
What really sets this project apart from previous approaches is thus that we are able to experimentally measure the consequences that arise when a primate lives either an independent or a highly interdependent lifestyle, which corresponds to the evolutionary contrast between the independent lifestyle of our chimpanzee-like ancestors and the obligate interdependence of modern humans. First and foremost, this will critically advance our understanding of the evolutionary origin of the human mind. But beyond that, our results may also have profound implications for general wellbeing and public mental health if it turns out that interdependence – or its loss in modern societies – has critical downstream effects.
These differences are most apparent in socio-cognitive contexts, such as Cooperation, Communication, and Culture – the so-called big-C contexts.
Intriguingly, what underlies performance in these big-C contexts in which humans excel is bio-behavioral synchronicity: the coordination of biological and behavioral signals between interacting partners. In short, we align, and tune in with our interaction partners all the time. This ranges from heart rate synchronization to hormonal and behavioral synchronization, and even to vocal alignment.
We thus know well that the gap between apes and humans is fundamentally social.
What we do not know, however, is why this gap emerged: Why was it exactly us, rather than any of the other great apes to evolve into such a hyper-social cognitive niche?
Several answers have been proposed, and some of the most influential ones stress interdependence as key factor. Compared to other apes, humans are much more interdependent: within foraging bands, for instance, fitnesses are intertwined. This is because we critically depend on each other, with regard to our subsistence of cooperative foraging with extensive food sharing, and also with regard to child rearing: we are essentially cooperative breeders and hunters. One influential hypothesis argues this explains why our minds have evolved to be so fundamentally prosocial. The problem is that these ideas and hypotheses are reconstructions, and at best supported by correlative evidence.
The goal of ENGINE is to go beyond correlation, and experimentally investigate the consequences of increased interdependence, relying on plastic responses (“in real time”) to an increased or reduced need to cooperate. Thus, we experimentally manipulate interdependence in a colony of marmoset monkeys, to be able to assess the consequences in terms of synchronicity at various levels (hormonal, behavioral, acoustic) as well as the performance in big-C tasks.
We chose marmosets because they are renowned for their excellent socio-cognitive abilities and cooperativeness, which are necessary preconditions to make the interdependence treatment possible at all. Like humans, they cooperate extensively, in particular when rearing offspring. Furthermore like humans, they tune in with each other, and synchronize at the hormonal, behavioral, and even vocal level.
What really sets this project apart from previous approaches is thus that we are able to experimentally measure the consequences that arise when a primate lives either an independent or a highly interdependent lifestyle, which corresponds to the evolutionary contrast between the independent lifestyle of our chimpanzee-like ancestors and the obligate interdependence of modern humans. First and foremost, this will critically advance our understanding of the evolutionary origin of the human mind. But beyond that, our results may also have profound implications for general wellbeing and public mental health if it turns out that interdependence – or its loss in modern societies – has critical downstream effects.
For ENGINE, we are thus engineering interdependence in marmosets, resulting in one lineage that is highly interdependent in their everyday lives and a second lineage that is not. Individuals in the high-interdependence lineage depend on each other in their daily tasks: for instance, they have to cooperate to receive their daily food. In contrast, those in the low-interdependence lineage face similar tasks and challenges but the animals do not need the help of others to overcome them. While the curious animals perceive all tasks as enrichment, they are building up a more inter- or in-dependent mindset over time, depending on the lineage they are assigned to.
Before starting these non-invasive treatments with the marmosets, we collected baseline behaviors for all of the animals, such as: social tolerance, prosociality, hormonal profiles detected from hair samples, social networks of the groups, their communicative behavior and vocalizations for acoustic analyses and parenting styles. We are also working intensively on the automatization of acoustic analyses and social behaviors using machine learning pipelines. Several tasks are already implemented for the marmosets, and to monitor the progress of the separation of the lineages we measure some behaviors repeatedly at regular intervals, in particular social tolerance, prosociality, and hormonal profiles from hair samples. For social tolerance and prosociality, for which the measures are immediately available, we already start to see the lineages diverge.
Since our ultimate goal is to understand humans, we are also validating a part of our studies with human subjects. In a current set of experiments with humans, we are measuring physiological synchronization when engaged in an interdependent task with a partner. Some of these measures, such as thermography, can easily be collected noninvasively in marmosets as well, which will allow us a direct comparison between marmosets and humans in the future.
Before starting these non-invasive treatments with the marmosets, we collected baseline behaviors for all of the animals, such as: social tolerance, prosociality, hormonal profiles detected from hair samples, social networks of the groups, their communicative behavior and vocalizations for acoustic analyses and parenting styles. We are also working intensively on the automatization of acoustic analyses and social behaviors using machine learning pipelines. Several tasks are already implemented for the marmosets, and to monitor the progress of the separation of the lineages we measure some behaviors repeatedly at regular intervals, in particular social tolerance, prosociality, and hormonal profiles from hair samples. For social tolerance and prosociality, for which the measures are immediately available, we already start to see the lineages diverge.
Since our ultimate goal is to understand humans, we are also validating a part of our studies with human subjects. In a current set of experiments with humans, we are measuring physiological synchronization when engaged in an interdependent task with a partner. Some of these measures, such as thermography, can easily be collected noninvasively in marmosets as well, which will allow us a direct comparison between marmosets and humans in the future.
In a first step, ENGINE helps us understand the extent to which synchronicity acts as social glue to facilitate performance in big-C tasks. With the two lineages of marmosets, we will test whether this entire system can be up- and down-regulated by experimentally manipulating interdependence. If marmosets show such plasticity, ENGINE really can contribute to answering the big puzzle it set out to solve, namely: How did the human mind evolve, and why did we become so fundamentally different from all the other great apes?