So, if you're interested in hearing a lyrebird sing and you'd like to watch you can go to YouTube and type in lyrebird, l-y-r-e, and there's lots of videos you can watch and see them singing. And the amazing thing is that there are these incredible mimics that hear songs, they hear sounds in the forest, and they can mimic them and you can't even believe that a bird could make the sound of, you know, whether it's another bird that has a complex song. Or they hear a camera or the camera shutter, and they can recreate that sound or even they can recreate the sounds of saws or car alarms, it's incredible. So this is something that if you're a biologist you'd like to understand and you'd like to explain, and that's why Tinbergen's four levels of analysis are powerful, and I want to walk you through them one by one. So the phylogenetic level Is understanding the history of a trait across species and time, think of it as like the genealogy of your family. Why is it that your family happens to have a lot of people with blue eyes or your family happens to have a lot of people who are tall? What is the genealogy, or when you're talking about different species, what's the phylogenetic relationship that allows for that trait in the current species you're interested in studying? So in the case of lyrebirds and trying to explain their song, it's interesting to know that they are in a family that happens to have complex voice boxes and their relatives tend to have the vocal apparatus that would allow them to make complex songs. So that would be one explanation for why lyrebirds have such beautiful songs and an ability to copy so many different things is that they're in a family that allows them to do that. So the ontogenetic level is the path by which a trait develops in an individual, so think about it as how you developed over time and that's exactly what ontogeny is, it's about development. So in terms of birds learning song, birds actually have different, different species have different ways that they learn song. Some species are born with a certain song that they sing throughout their life, they have to practice a little bit, but even if they are isolated from other birds as baby birds, they will develop the correct song for their species. There are other birds that actually have to learn their song, but there's different types of learning. There's age dependent learning where there's a specific critical period where the bird has to learn the song and it has to hear the songs of other birds to then copy and practice those songs. And the final type of learning throughout life is age independent learning, this is birds who learn songs throughout their lives, they can learn songs each year if it's the case of seasonal bird learning, so there's some birds who only learn in the mating season or right before it. But then there are birds like the lyrebird that are age independent and time independent, they can learn new songs any time and they can learn all sorts of new things, they're mimics. And that's why, from an ontogenetic level, you can explain why lyrebirds sing the way that they do. Okay, so, at the functional level, then the question becomes, what is the payoff that any trait you're interested in explaining has for reproductive success? Why is it that an animal, basically, how does the trait you're trying to explain, in this case, bird song, how does it pay off? What is it that it does to help with an organism to have more successful reproduction and successful survival? And in the case of the lyrebird song, what's thought is that lyrebirds are a sexually dimorphic species, males have beautiful plumage, are slightly larger than females. While females are the investing sex, they invest in offspring, and they sit on the nest, and spend more time investing in energy in creating the eggs and and the nest, etc. And so females are very picky about which male lyrebird they're going to take as a mate, and one of the ways they can choose the mate that has the strongest genetic value is the bird that has this long plumage and has this incredible ability to mimic. And it ends up that females are attracted to novel songs, and males that can produce the fanciest, most novel songs are the ones that typically the females swoon over and choose as their mates. So that would be, at the functional level, why do birds have this complex song? Because female lyrebirds prefer it and the males that are able to produce those songs are gonna have more offspring and a higher payoff for that trait than those that don't have it. So the final level is the proximate level, now this is where I think most people think about when they're trying to explain a behavior. They're trying to say why is it that a dog is able to solve that problem? They wanna know the mechanism, what's, as we've talked about in terms of cognition, the internal process and what are the different explanations that might be there. So we've all ready talked about there can be different types of proximate explanations, so in the case of song learning in lyrebirds, well, let's think about the neurobiology. We know a lot about how humans have different parts of the brain that are dedicated to different functions whether it's understanding the sounds that come in when we hear spoken language and then comprehending that. Or different parts of the brain that are involved in the production of language, and there's a network that is involved with human language. So that would be a mechanism for how humans produce language and the same thing can be said for the lyrebird. There's going to be an underlying neurobiological mechanism that allows lyrebirds to learn any song, any time, whereas other birds can't do that. So, that would be a proximate explanation, if we could figure out what it is about their brain that allows them to learn this way. Of course, also, even just understanding the cognitive mechanism, how is it that they're able to learn and mimic in a way that other animals can't? So those are the four levels, the Phylogenetic, Ontogenetic, Functional, and Proximate, but the interesting thing, and why they're so powerful, is all levels inform one another. If you understand the Phylogeny of a behavior it helps you understand the Proximate level, if you understand the Ontogenetic level, it helps you understand the Functional level, and so on. And all traits can be explained at each level, and the most important thing is that all levels are needed to understand the evolution of a trait. So, to summarize the ecological approach to cognition in evolution, from an evolutionary perspective, evolution is defined as a change in allele frequency over time, very simple. Evolution can be studied at four levels of analysis, specifically if we're talking about behavioral traits that we want to explain especially. Niko Tinbergen was the one who came up with that way of thinking about it. Ontogeny, Phylogeny, Proximate and Ultimate levels of analysis are complimentary, but of course, not mutually exclusive. If you're explaining a behavior at one level, it doesn't mean that the explanation on another level is wrong, they're completely separate and they inform each other. Different levels inform one another, as I just said, and lead to really powerful tests of different hypothesis, and sometimes inform how to test a hypothesis at a different level and that's what makes it so powerful. So to understand dog emotion and cognition, which is what we're really interested in this class, we have to study dogs using all four levels of Tinbergen's analysis.
