 human brain evolution and play as an adaptation for childhood learning education. Thank you, Paul. This is my fourth AHS, but my first time actually speaking here. All right. Play. We all love to play, right? There is the primal play session this morning, primality, and we're going to try and get lots of play in between all the sitting that we're doing. And there are some pictures up here, including, of course, the obligatory pictures of my own children here and here. But doing what children love to do best, which is, is this what a pencil is for? Well, according to this boy, at that moment, it adds what a pencil is for. Is this slide supposed to be walked up? Like, at my kids' summer camp, they say, no, no, no, you have to go down the slide. Why? I don't know. But this is what some kids want to do. They're not playing, skipping stones. It seems to be something that we love to do, but it's frivolous. You know that. The puritanical spirit of America lives on, because we know that when we go to school or when we're in our home environment, we're told that we're supposed to be focusing on the lesson, studying, doing our house tours. Those are the proper things for children to do. They have a little play on in between. This is what a lot of children spend, are encouraged to spend their time doing. Yet play is a human universal. When you look at cultures all around the world, including hunter-gatherer societies, foraging societies, what you find is that play of, mostly it's social, but it could be individual as well. It could be quite clever and creative. I just love this picture here of the children creating quite a nice circle with their feet. Just beautiful examples of play. It's a human universal. What an evolutionary psychologist would say, there must be some basic instinct or a module or some kind of part of our nature. It's part of our human nature. This is a nice way to dovetail off of the prior talk by Dr. Natterson in bringing in a little comparative perspective. Play is also an animal universal. Pretty much everywhere that it's looked for by zoologists and animal behaviorists, you find examples of play. I've actually seen this along the coast of Malibu. I've seen dolphins surfing. There are some really amazing videos of dolphins blowing and creating and producing these ring bubbles, air bubbles that they play with. The cat and mouse, dogs, rough and tumble play is very important, especially during the younger period, like the adolescent period of a rodent's life. Monkeys play. Even invertebrates like wasps, in this case, engage in things like rough and tumble play while they're young, especially, before they're actually competing over resources. So play is also an animal universal. Now despite being an animal universal, play has some unique features among humans as well. We play with poetry, song, so a lot of verbal language-based play, rhyme, music, storytelling. We have games that have rules, quite elaborate rules that we can follow. We could play all the way into our old age, and there are some instances of animals playing into their old age, but it's not to the extent that humans incorporate it into their daily lives. Pretend play and make believe. You might see some people here, some familiar faces, Chris. This is what happens when you become my Facebook friend. Your Facebook photos are a fair game. Peter Ballerstet, who I know is here, I don't know if he's here today, but he's going to be around during the conference doing some music. So there are some aspects, many aspects of human play that are unique, especially going into adulthood. So why do we like play so much? If the drive to play is a human universal, it's likely to be some kind of behavioral adaptation. But what is play for? What is its function as a biologist might ask? Is it merely to relieve boredom? So when you have nothing else to do, you start fiddling with things and making things up to pass the time. Or is there something more fundamentally important about play for the human and for the animal condition? I want to talk a little bit about some work by Blurton Jones and Connor, the male Connor who spoke last year at AHS 13, and a study that they did among the Kung Bushmen of the Kalahari Desert. And they had done a study back in the 70s where they questioned and surveyed the knowledge of the adult Kung people, of their knowledge of animal behavior. And they compared that to the knowledge of scientists, such as ethologists who study animal behavior for a living. The Kung appear to make a good deal, they know a good deal about their subjects. More than many of the local scientists did. Another very interesting fact is that they separate carefully data from theory and they discriminate observed data, their own personal knowledge of what they've seen and witnessed from secondhand information, what they've heard others report to them. And they put a much greater emphasis on their own firsthand experience. Also, it turned out that their procedures of data-gathering, analysis and interpretation resemble the methods of modern-day western ethology and were very sophisticated. Why would that be the case? Why would they be so observant and so analytic? Well, hunter-gatherer lifestyles are based on the long-term development of knowledge and skill. This allows for planning and inference and the cultural acquisition and cultural modification with further acquisition across generations. So this process of intergenerational transfer of accumulative culture with generation and incorporation of modifications and innovations requires what I will say requires a long period of research and development during an extended phase of human development. So let's contrast human anatomy, physiology and ecology with that of the extant great apes, especially our closest living relative, the chimpanzee, to look for clues for the functional role specifically of the human type of development and play and how play might play a role in human development and evolution. So here's a little phylogenetic tree of the great ape clade, or actually the primate clade. Humans and chimpanzees both share a common ancestor going back about five to seven million years, it's estimated. And as we saw with the previous talk, this was also mentioned that we share about 98% of our genome with chimpanzees. And the large differences that we see between us and chimpanzees is likely due to a small number of regulatory genes that were targets of selection. And these genes will turn out, we'll see some of them play an important regulatory role in development. So what are some of the ways that humans are different? Humans as we know are big brain primates. This curve is plotting encephalization quotient which is just a measure of the brain size divided by body size. So how brain-y, how much brain is an animal made up of for their body size? And also for all of the talks, all of the slides I'm pulling are not my slides for the most part but are slides I'm drawing from the literature. For example, this one comes from ILO and Wheeler, Current Anthropology. So I put the source at the bottom of each slide. And what we see here is that the encephalization quotient, the EQ of Homo sapiens is well above the other, even the other Homo species and Australopithecine species of hominid as well as gorillas, pangos, so the other great apes. We're very brain-y creatures, Homo sapiens. This is also from ILO and Wheeler and this is just showing you a picture of the gross anatomy of the different great apes plus the lesser apes, the gibbons. And there are some striking differences that come out comparing humans to the rest of the great apes. We have very large hind limbs and very short forelimbs. So we have a specialized locomotion and that's something that evolved before our brains even got beyond the size of a chimpanzee brain. So this was the first step, so to speak, in the march toward modern-day humans. We also have a short torso and a specialized diet and a large brain and small jaws. Again, indications of specialized diet as well as a different kind of intelligence. So what this is now showing is the cranial capacity or the size of the skull which would house the brain for Australopithecines, Homo habilis, Homo erectus and both old or archaic humans and modern humans. And what you see is that all the Australopithecines, their brain capacity, cranial capacity is about the same as modern-day chimps. It wasn't until Homo habilis that you had this increase in cranial capacity that continued into Homo erectus but then it really took off with the very modern-day humans and we'll come back to that point. Oh, and also this is also a figure probably many of you are familiar with this. It's been on a number of people's blogs but it's from the ILO and Wheeler paper showing that in order for a larger brain to evolve in humans, something had to give about these metabolically expensive tissues and the way that it worked for humans is that we shortened our gut, especially our hind gut. So with a higher diet quality, by moving to a higher diet quality and I'll talk about how we did that in a moment, it increased the amount of energy available to devote to a large brain. It also allowed us to not devote as much energy into developing and running a small gut so again our guts could basically get smaller and therefore this is the trade-off of the evolution of the human brain and it was all because of this shift to a higher diet quality. Well, how did we shift to a higher diet quality? What allowed hominids to move to that type of diet? Well, let's look at the evidence from the evolution of tool use. So Homo habilis has, which lived about 2.4 million years ago, the earliest fossil remains, is accompanied by the first real extensive stone tool technologies in archeological record. And Homo habilis had the ability of the manual dexterity of like a modern day human and very different from a chimpanzee or other great apes. And Ambrose in a nice review of the evolution of tools in archeological record has some good, some fascinating statements. One, he says that Oldewan technology seems simple, reflecting the mental capacities of extant apes, but it actually reflects manual skills far exceeding those of a chimpanzee. A chimpanzee cannot do the certain types of grip and strike that is required to craft tools that are then capable of extracting marrow from bones, for example. And then the next step in the evolution of human tool use occurred among Homo erectus and some of the best archeological remains are from about a million and a half years ago. And they started creating these bilaterally symmetrical blades. And bilateral symmetry and the high degree of standardization of the Ashilean handax and the shape over a wide range of sizes implies a well-defined concept of shape and proportion, which reflects a higher conceptual and cognitive abilities than was required for Oldewan technology. So just as the Homo erectus started having larger brains in Homo habilis, their tool technology also reflected a higher amount of cognitive needs in order to create them. And then also the controlled use of fire, which is the first really strong evidence about a million years ago, emerges. So these are also shifts to a higher diet quality. Then with Homo sapiens and Homo neanderthalensis, about 300,000 years ago, we get even another shift, a grade shift in the complexity of tool use. And now we're going, the tools are accompanied by the remains of megafauna, large elephants, giant sloths, ruminants, other large mammals. And again, Ambrose writes, stone-tipped spears, knives and scrapers mounted in shafts and handles represent an order of magnitude increase in technological complexity that may be analogous to the difference between primate vocalizations and human speech. So a much more open-ended process of constructing these stone tool technologies. The acquisition and modification of each component of a composite tool involves a planned sequence of actions. And I start that because we're going to talk a little bit about the evolution and development of the forebrain, which is different in humans than among chimps. So these planned sequences of actions that can be performed at different times and places, such as flaking a stone point, cutting and shaping a wooden shaft, and collecting and processing binding materials. The final discussion of tool use I'll talk about, and human diet that I'll talk about, is with the final stage of brain evolution, where we really change the rate in the last few hundred million years among the archaic and modern humans, the rate of the increase of the cranial capacity. And that's shown here in the last few hundred million years. And one hypothesis that seems to be getting a lot of support is put forth by Stephen Kunane, and there's a really nice book that edited volume that is about this topic. How the freshwater and marine food resources were really important for this final rapid expansion. And this is from a recent paper by Brown et al. It's a different group that's showing that in some of the human brain important nutrients, like DHA, iodine, copper, iron, selenium, sodium, things like that, were very important, especially during human brain development, are the highest density in both plants and animals along waterfront environments, coastal environments. And this is from a archaeological site in the flood plains of southern England and northern France. But there's one example. I have other examples from other parts of the Mediterranean from Africa showing the same phenomenon that humans in the Homo archaic to modern humans were moving to a water coastal environment. And here's some pictures of some of the types of tools, really fine-grained types of tools, as well as art objects that started occurring, both ornamental and abstract art that occurred. And especially about 80,000 years ago in South Africa, some of the earliest examples of these really fine-grained and advanced tools that allow hunting and for both microfauna and other kind of plants along the shoreline environment. So what all this means is that, as Kaplan had all talked about in a paper about a decade and a half ago, is that humans had dramatically shifted our food pyramid, so to speak, compared to that of our closest living relatives at chimpanzees and other non-human primates. So for us, the large and small game, and I would add to this with the more recent data, the water environment types of resources, require high degrees of skill in order to extract those resources from the environment compared to insects and fruits and leaves, which require less types of skill, which is what the chimpanzees, mostly forage on leaves and fruits, some insects, and they do capture some game, but it makes only about 10% of their dietary intake. Whereas for humans, we are reliant on these kind of resources as a major part of our diet. It's kind of funny, if you think of this chimpanzee pyramid as what the modern human food pyramid is like by the USDA, except you'd add grains over here. And this other one looks kind of like the paleo diet pyramid, right? So this gives us some clues. The clues for how we were able to acquire these skills to create these tools and use them and modify them comes from looking at human life history. So here's some interesting data about human life history, again from the work of Kaplan and colleagues, some anthropologists, showing that compared to chimpanzees, these are mortality curves for the proportion of individuals that survive at 0, 5, 10, up to 75 years old, you see that chimps have a dramatic decline so that half the chimps have already died by the time they're about 10 to 15 years old. Whereas for humans, half of the humans born in these are different hunter-gatherer groups have died or survived to about, depending on which group you're looking at, 40 to 50 years old. And a significant portion, 20 to 30%, survive all the way into their 70s. So this is the proper way to look at human lifespan. The other really fascinating thing to think about that's really human unique is what's shown in this graph. Let me unpack this for you. So what this graph is showing is the survival on one side. So these data are for chimpanzees and for humans. So it's replicating these data. But I want you to focus on this. This is the net production of calories that go into the group, that are contributed to the group, either to self and or others. And for both chimpanzees, which is this curve here, and for humans, which is this curve here, you start out extracting calories, right? You're breastfeeding. So you're taking calories from mom. Chimpanzees wean by about five to seven years old completely, but usually by about five. And then they're basically foraging mostly for themselves until they start reproducing. Then they're contributing to their own offspring through breastfeeding and sometimes hunting and sharing resources. But very little contribution of the individual to society. Mostly it's to their own offspring. Humans, on the other hand, have a quite dramatically different net production curve. We start out like chimpanzees, you know, taking nutrients from mom. But after weaning, which we do earlier than chimpanzees, even among natural populations, we start consuming more and more food, but it has to be acquired and given to us and fed to us from our parents, from grandparents, other people, siblings. And it's not until we reach the age of about 20, you know, on average, that we start becoming net producers. And then we start producing a lot, like by capturing big game or digging up lots of tubers. So whether you're gathering or foraging, both of these activities can provide a lot of calories and nutrients that are then distributed and shared. So we adults are subsidizing the children for a long period of time, almost 20 years. So that's a big clue to why play might be so important. So let's also look at early stages of this subsidization process. So humans are born with about 15% body fat. So by the time when we come out of the womb, we're very fat animals. And these are just some other animals for which we have data. Chimpanzees are about 3%, so very low on the scale. They're not shown on this, but I get it from another source. Actions like guinea pigs are pretty high. Harp seals are pretty high. But what's also interesting and not shown in this graph is that for humans, almost all of this, about 10% to 12% of that 15% is white adipose tissue. Whereas these graphs for all the rest of the animals is primarily brown adipose tissue. Brown is the thermogenic heating, is metabolically active. Whereas the white adipose tissue that humans are born with is a layer, a subcutaneous layer that coats our skin. That's all the fat baby arms that you don't see on chimpanzees or other mammals. And then even after birth, from birth to about 10 months of age, human males and females pack on a lot of weight and by fat. The fat percent goes up to about 25 to 27%. And then it drops off so that by 5 years old, you're approaching more a 20% range. So we need fat. We need to be fat. I know the Twitter bugs over there tweeting this out. We need to be in ketosis, right? So one reason for this need is a shift in brain development among humans compared to the great apes. So if we look at apes and they go through different stages of development, from infancy to early childhood, a real brief middle, actually there is no early childhood for apes, they go from infancy to middle childhood, a brief adolescence, and then they're basically adults. Humans have a little bit shortened infancy but we have this long period of early childhood. The preschool to kindergarten, first grade, maybe second grade years is actually a unique stage of development, of mental development in children. Then we go into the early childhood years, become terrible middle schoolers. And then we have this protracted adolescence before we really go out to becoming breeding adults. We become sexually mature, but after sexual maturity, we're still not acting on, and most cultures not acting on that, and we're still learning a lot. And two concepts I want to bring in, that I'm going to talk about, include these ideas that the way that you shift, the way that an animal develops is by changing the genes that regulate the developmental process. So you can slow the rate of development down and use what's called neoteny, where by the time you reach adulthood, you retain youthful traits like playfulness, curiosity, and laughter, or by slowing it down and keeping the process going even after sexual maturity has reached in humans, but keeping the brain growth process going, you can add new features. This is called hypermorphosis. Add new features such as language, tool use, cooperation, humor I would even say. I'm not sure how I'm doing on time. Oh, perfect. Okay. If we look at just the way that a modern human infant versus a modern chimp infant's brain develops, postnatally, we find that looking at the graphs on the left here, the chimpanzees don't change a lot. After birth they do change. Humans change a lot more, but what's interesting is that the chimpanzees reach the adult size sooner. That's what these green dots are supposed to show, is that they reach the adult size, which is about 100% sooner than do the human. So human brain development, just the amount of brain tissue being added, is slowed down. Also, more dramatically, is that a bigger change in humans in the shape of the brain. So the heads is changing quite dramatically, whereas for a chimpanzee, it doesn't change nearly as much. So there's a lot of structural changes going on. But in addition to that, there's a lot of more structural components of the neurons themselves that are quite different in humans than there are in even chimpanzees or the rest of the mammals. So one thing to point out is that humans went through two duplication processes of a chromosome, of a gene on a chromosome that codes for dendritic spine density. What this created is humans having much denser spines. And what spines are, if this is a neuron, these are dendrites. So the dendrites receive information from other neurons, the axons of other neurons speaking to them. And so basically what the number of spines means is there are more connections. There's talking, more communication between this neuron and the neurons that are connected to it. And so with the dramatic increase in spine density, there's this dramatic increase in the connections. So there's a term called the connectome that's emerging. And so there's a much larger human connectome than there is a chimp connectome. Now that's important because although you start life as a young infant, producing all these connections through the gene expressing early in life, what's really, really important then is that you then go through a phase of paring down or pruning those connections. It's like a beautiful bonsai tree, a bonsai tree is created by first starting with a bushy tree and then pruning it back to a beautiful structure emerges. Or sculpting, you start with a big block of clay and you take away until you have something beautiful or functional. That's the way that brain development occurs. And by starting with a larger lump of clay, essentially more connections, it allows a synaptic pruning process to happen at a greater scale and this is the key to creating the abstract level thought or abstract representations that we have is through the synaptic pruning. And another paper about genes and evolution, I don't expect you to get all the stuff on here but what I just want to pull away from here is that there was a recent study looking at gene expression in the prefrontal cortex and comparing it to the cerebral cortex as a control area. But the prefrontal cortex we know is an area that goes through a long period of maturation in humans, even in other mammals, it's one of the last areas to fully mature. But in humans that is delayed until your early 20s. So the kids in my college class when I'm talking about this, I said your prefrontal cortex is finally starting to reach final maturity and finally starting to show because that's when the prefrontal cortex is involved in planning and cognitive flexibility in a vision of impulsivity, right? All the traits that adolescents seem to lack but in our 20s hopefully they're starting to sink in. And so this is a study that looked at gene expression in the prefrontal cortex and there's a 12-fold increase in human-specific genes expressed in the prefrontal cortex compared to chimps and they also compared it to macabre monkeys as well. When they looked to see what the nature of these genes were, what they found is that they both through DNA analysis and RNA analysis, they found that they clustered into five what they'll call human-specific modules. And what I just want you to take away from this is that the human curve showing age and years of the individual for humans versus chimps and macaques and this is the expression level, the amount of this gene that's being, product that's being expressed. It starts out very high for module A, we'll talk about it in a little more detail. It starts out very high in chimps and macaques and then decreases whereas for humans it starts out low and it doesn't peak until we're about three to five years old. That period, remember that human unique period of child development? It's also the period when these genes are reaching a maximum. Some of these profiles of humans and chimps look similar and some they're different. The point is that it's a developmental shift. It's not that we necessarily only have different genes but we have also different, the timing of the genes is different. I'm going to come back now to this first, this M1 module and don't worry about all this kind of clustering here. What it's basically showing is that the types of genes, what they're, what's being expressed by these genes in this module are things that involve learning and memory like synaptic transmission, long-term potentiation, which is the cell molecular mechanism of learning, long-term memories, as well as calcium signaling and ligand receptor interaction. The fact that this reaches a maximum much later developmentally than in other primates and it stays on for longer into adulthood than it does for the other primates. This suggests that there's a developmental heterochrony or difference in time in the development of human brain versus other primates and that there's a special three to seven year period for humans that's related to the beginning of the development of the prefrontal cortex and as well as other areas that are looked at. So it coincides with this period of cognitive maturity, specifically self-regulation, abstract thinking and social behavior that starts to emerge in the first grade, second grade. Now let's come back to humans in the wild. So adult humans like to play, create, explore, wonder, tinker, infer to think. And we know as I already said that the human forebrain that modulates a lot of the long-term planning and flexibility is expanded in humans and it doesn't fully mature into your 20s. So what does this mean in terms of coming back to the life way of a hunter-gatherer? Why is this important? This protracted period of brain maturation and slowed down and protracted allows for the complex level of knowledge acquisition, short-term and long-term planning, skill-based hunting and foraging, inference and counterfactual reasoning. We're all born philosophers and scientists and other of these traits. And so the question is, well, modern-day schooling teaches this stuff, right? That's a great environment for modern-day kids to go and learn to be like this, develop those skills. But if you think about the core values of schools are in the modern educational system, it's strict adherence to rules, a top-down hierarchy, orderliness, rigid schedules of activities, to risk averse, minimizing divergent thinking, common standards, common metrics of learning, one size fits all, right? Emphasis on conformity and homogeneity, despite the lip service to variability. Can formal schooling, which seems so different than what we think of as a playful primate, can it impair normal development? Or is this just, am I just saying this is a problem, but really it's not a problem? Turns out that there's a lot of evidence that this is a problem, that it is interfering with normal human development. And here's a really fascinating study I love, and this is a study of second, third, and fourth graders. They were tested on the effects of teaching computational algorithms, such as the property of carrying, like, you know, seven plus eight, does this carry the one, that kind of stuff, those algorithms we all learned in school. Some children had been encouraged to invent their own procedures and had not been taught any algorithms from grades one to two or from one to three. Other children in the same school but with different classrooms were taught the conventional algorithms prescribed by textbooks. Then the students in these studies were asked to solve multi-digit addition and multiplication problems and asked to explain how they got their answers. Really quickly here, the no algorithms group, some algorithms, algorithms. This is just one example of the answer they gave to seven plus 52 plus 186, and these are among the second graders. 17, 19, 20 subjects in each condition. The one that never taught algorithms, encouraged to invent their own, about 45% of them came up with the right answer. The ones that had some exposure to algorithm training, only 26%, the ones that had been taught the standard practice of going through all the algorithm training from the math textbooks, only 12% came up with the correct answer. That doesn't look good. More fascinating and more telling, I think, is that when the students were wrong, some of them were wrong, the ones that were using their own algorithms, their own way, were much more likely to be close to the correct answer. They were not there, they were close. Whereas the ones that were taught algorithms, as if they were just blindly following them, they wouldn't recognize that they were completely out of the ballpark. I mean, completely. So, not only and so the authors of this paper say, not only is it a problem in terms of inhibiting performance of basic math skills, basic math number sense, but that algorithms are un-teaching place value and they're hindering children's development of number sense. I'm going to skip this in the interest of time. I want to talk about another real classic in child development type of cognition and this is one that involves folk physics, our kind of everyday common understanding of the way the world works physically and I'm going to play this little video while I'm talking and this is going to show you a test of conservation of volume and Piaget, one of the pioneers of child development had come up with this test. It's okay, I'll just describe what happened. So this test involves there are two glasses of liquid of the same glass, the same amount of liquid in each. So it's the same volume, right? Well, what the man does is he pours the volume of one of those or pours the liquid into a very tall thin cylinder so that the liquid comes up to a very high level and then he puts the cylinder next to this other one that hasn't been touched and he asks the child, do they have the same amount or does one have more than the other? And in this test in the video if we saw it the child would point to this, the tall cylinder say it has more because it's taller, he says. That's a failure of conservation of volume. Initially all children make that failure. And at some point during development they kind of understand that oh, even though it's shifting, it looks different it's the same amount. So it conserves the property of the volume. And so there's all of these kinds of conservation tests. They're called perceptual invariance where a perceptual transformation but you still see it as the same thing. He recognizes the same thing. And it turns out that formal cases delays or even reverses perceptual invariance so that children are no longer able to recognize. So they get to the point where they understand that the two are the same but then they lose that through formal schooling. Oops. Here's a very recent paper, really interesting from the Frontiers in Psychology and what these researchers did is they assessed how much, so it's an observational study, they assessed how much structured activities versus less structured activities the child, children, participants in the study the parents reported of their children. So the parents reported how much time their child spent in lessons, tutoring, homework, chores, religious activities, organized meetings and those would categorize as structural activities. The less structured were unguided, selfish, initiated practice so if the student wanted to study on their own or learn something, free play, shouting, enrichment activities, going to zoos, entertainment and then they measured the verbal fluency of the children with a higher verbal fluency score indicating more self-directed control of their own behaviors and the children's time in less structured activities correlated very positively with their verbal fluency. So what that means is a time in less structured activities correlating positively with verbal fluency is a measure of self-directed executive functioning, again a frontal cortex kind of behavior such as goal-directed behaviors not explicitly specified by an adult. So we have to remember that the modern education system was really born in the industrial age and it was born to serve an industrial age lifestyle. So it's skill-based, test-based educational practices to get people ready for a labor force. It impairs many aspects of cognition, cognitive development, emotional even social development. It's associated in other literature with an increased incidence of ADHD, attentional disorders as well as mood disorders like depressive and anxiety disorders. Also we think about the way the development happens. This is a nice slide that kind of gives us the way that as we're developing, think of this ball going down this sheet as development, there are inputs, the forces from the environment guiding the course, the track that that little, the ball takes our development takes. And if there's an absence of expected inputs or inappropriate inputs, the presence of inappropriate inputs, it can cause the developmental process to derail a process called decanalization. So this process is called canalization. If you impair it, it can cause decanalization where improper development then occurs. And this has been directly linked to a lot of the increases in schizophrenia and autism in a paper by McGrathen at all in Psychiatry Journal. I would say it also is the case probably for creativity, intelligence and mental health. We live in an information technological age. I mean this conference was born from the information technological age in social media. In our society we need to produce individuals who are creative, analytic, innovative and generalist problem solvers with well-functioning brains, minds and emotions. So how do we do this? We I think have to return to play in exploration as a child's natural ability to educate him or herself. Children are born with the adaptation act as scientists and philosophers. And how many time do I have left now, Paul? Five minutes? What? Okay, so alright, I'll summarize very quickly by saying a recent paper by a colleague and friend of mine, Alison Gopnik, right here at UC Berkeley and some of her colleagues. A paper called The Power of Possibility, Causal Learning, Counterfactual Reasoning and Pretend Play. And they really talk about how this change in developmental program led to a uniquely long period of human child development for the immature proto-humans children to have long period of learning and development through free exploration and play. And I'm going to skip some of these slides and basically talk about how pretend play, another obligatory slide of my kids, and use of imagination is critical. And so in order to go forward we need to be able to foster an environment where this innate neuro-continental developmental mechanism is allowed to express itself naturally. So that the child can have a greater chance of becoming an adult that can both thrive in and contribute to society with a reduced risk of maladjustment and greater health and well-being. Thank you. Testing, hello? Is this not on? Mike? For the questioners? Hello? Hello? So Erin, you're talking primarily about cognition here, it sounds like you said that we want to create, invent, wonder, tinker, infer, and all those things. And I'm thinking, you were talking about the evolutionary history of tool usage as kind of the main thing that we were relative to our brain development. But I was wondering if you also have looked into the running man theory and the connection between the physical development as we developed running and how that, because Dan Lieberman focuses a lot on that, about how that influenced brain development, because it seems like the social and physical aspects of play that would go along with our relationship between our physical capabilities and our brain development would also be really important in addition to the cognitive components. I recognize that. And I'm a cognitive psychologist at heart and so no, I didn't really consider those. I have thought about them, but I haven't looked into them. And I'm not claiming that this is the biggest picture, the most biggest part, but is an important part. Thanks. All right. Just a moment. I just want to let everybody know that the next session in both halls will start in five minutes. So if you want to go to Bancroft, this would be a good time to leave. It's also not a bad time to go to the restroom if you want to do that. And let's use all five minutes for questions if there are questions. Go ahead. I know that in your the study you talked about with the algorithms teaching kids addition and also in the example of the Kung it seems like a lot of the play that helps children learn is still somewhat guided that there is a purpose to it to develop certain skills. So how do you balance having to help children learn a skill by giving them the freedom to learn it in a way that's natural? That is a great question. And that's the kind of thing we should be focusing on in society and modern education and look at the examples that are out there from Montessori schools even something as radical as what Peter Gray advocates of the kind of really open schools I forget the name of it offhand but to what other foraging groups do and usually it involves mixed ages and there is a lot of guidance but it's usually not in a forced as structured way unless there's some need of structure but the structure is usually only there very quickly to be withdrawn my understanding and so but I think there needs to be more understanding that there's that there could be different ways of doing it. Thank you so much and your talk hit home so much I have a first grader who will go into first grade next year and she's been in a total play based school and it's shifting and I just I wake up in the middle of the night thinking oh she's not going to be outside enough and playing enough I just do you have suggestions for besides homeschool what do you do? I mean a lot of people are turning to homeschooling if you have an access to a lot of other children of mixed ages then that's a great way to go I know Ben Greenfield I believe homeschool is his children he's here at the conference he could pick his brain about it maybe I don't really know I'm struggling with this too I have two daughters one going into first and one going to fourth grade and they seem to be doing well and I try to give them as much free play and stuff at home while still making sure that they're following the convention of doing homework because I know that it's part of our cultural system and I want them to thrive in that system so I make compromises and it's really an individualist thing and I haven't hit on the right formula but I would just say knowing that you're concerned about this is the biggest step you can take so one thing I was curious is how different cultures and different countries have different educational standards that might have less formal education and incorporate more play and more creativity that might help foster cognitive development I was wondering if you looked into those I haven't really researched other cultures as much I've more relied on the literature on human foraging groups like Hunter Gathers but this talk and this topic is so huge and broad it delves into so many domains I can only focus on a few at a time literature out there on that so I think there's some speaking to a critical period based on what you were saying and there's a lot of current work as far as vision as maybe the critical period wasn't as important as we thought into developing vision I was wondering if you think that there's some potential in later age for humans to develop these skills that they would in the three to seven years if there's some plasticity in that very good question and I think there is less there's a weakening of the idea of the critical field it's still there are developmental windows and we recognize that but I think there's more plasticity in overcoming them than we realize but it's hard to say because it takes a lot of effort to do this like anybody learning a second language or overcoming from a bad traumatic childhood that could be very difficult to deal with any kind of mood disorders that might arise from that and untraining those from yourself hi I don't have a question actually I just wanted to say I grew up in Waldorf and given a lot of the concerns you brought up in public school I think it addressed those miraculously and I also went to Montessori in public and so comparatively speaking I think Waldorf really really rocked it for me so that's great and if public schools can emulate some more of those practices give more freedom then I think it would be a big step in the right direction I just want to mention briefly the free form less structured school it's multi-age would be a free school I think you were looking for that term so free school is a group setting and then also unschooling is one of the types of homeschooling that would also be that more on an individual family basis and connected with the community and travel and all that so thank you so our next talk is starting in 10 seconds so this is a chance to rearrange yourself find a seat if you're in the corridor