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HUMAN BEHAVIORAL BIOLOGY NOTES .BIO 150
ETHOLOGY: THE STUDY OF BEHAVIOR IN NATURALISTIC SETTINGS
"An experiment should be like a conversation with an animal.....but in the animal's own language" - Niko Tinbergen “The experimental analysis of animal behavior is for those who like physics; and ethology is the study of animal behavior by those who like animals” - Han-Lukus Teuber “Pigeon, rat, monkey. It doesn’t matter” - B.F.Skinner
Ethology and its origins as a backlash to behaviorism If you want to study the behavior of an animal, there is the broad question of whether to do so with the animal in captivity, or in the wild. The biggest trade-offs are obvious – on the one hand, an animal in captivity is observed more easily, and its environment (and its effects on behavior) can be controlled, but the behavior of the animal can readily be distorted by the captivity.
Ethology is a branch of animal behavior that developed in Europe during the early and middle parts of the 20th century, and its basic premise is that behavior can only really be studied, even in the context of experimental studies, in the natural habitat of an animal. To get a sense of where ethology was coming from, it is necessary to first see something about behaviorism , which dominated American psychology for much of the 20 th century.
American psychology, circa 1900, was a very introspective field with no taste for experiments, or quantitative data. You didn‘t pass out questionnaires to large numbers of subjects, or document the behavior of people put in unlikely settings or, most definitely, study animals. Temperamentally, it had a lot in common with philosophy. All sorts of claims could be made about the nature of the mind, the workings of the brain, what behaviors are instinctual. Not much of a science. Behaviorism developed as a backlash to this, starting around 1910 with one of its founders and boosters, John Watson , and reaching its heights mid-century with B.F. Skinner. These folks hated this fuzzy, navel-contemplative style of philosophical psychology. They consigned ―mind‖ and ‗brain‖ to being black boxes that couldn‘t be observed, and if something couldn‘t be observed, measured and quantified, they weren‘t interested – all they cared about was that environment went in to the mind/brain black box and behavior came out the other side. Their organizing principles basically were:
- Radical environmentalism. It was Watson who was constantly making
pronouncements along the lines of, ―Give me an infant of any background, and let me
control the total environment in which he is raised, and I will turn him into whatever I wish, whether doctor, lawyer, beggar or thief.‖ Skinner expanded on this with the notion of ) lOMoAR cPSD| 56091590behavioral engineering – control environmental variables and you can produce societies with no unpalatable behavioral problems, an idea that he became famous/notorious for in his utopian novel Walden Two. -- Reinforcement theory. So environment controls everything. What aspects of environment? And behaviorists stripped it down to the barest of ideas – reinforcement increases the likelihood of a behavior occurring again, punishment decreases its likelihood, and by doling out each appropriately, you could shape behaviors at will. Later generation behaviorists developed highly mathematical models about the relationships between reinforcement rates and behavior rates, but this was the basic idea. And this gave rise to a very pared down style of experimentation – a test environment in which, ideally, only a single behavior, in response to a single type of reinforcement, was being studied. Thus, you‘d have a hungry rat in a box (called a Skinner box), where one would be studying how often it would be pressing a level (behavior) in order to get a pellet of food (the positive reinforcement). The cleaner and more atomistic the experimental design and environment, the better. (As small elaboration on the field‘s jargon, ―positive reinforcement‖ refers to giving something in order to shape a behavior, whereas ―negative reinforcement‖ refers to removing something in order to shape a behavior) .
- Universality. So according to the behaviorists, get the rules of the field down and you‘re all set with anything that behaves. This generated statements from Skinner like, ―Pigeon, rat, monkey, boy, it doesn‘t matter.‖ And thus, the species that you study is merely a function of convenience. Study an elephant in an appropriately sized Skinner box and you‘d get the same general scientific answers as studying a mouse in a Skinner box, but the latter would simply be easier to study. Cold, joyless, dogmatic droids, if you ask me. Ethology arose in central and northern Europe, in some ways in reaction to behaviorism, and in some ways, in blissful ignorance of it. There‘s this image, circa Darwin, of the butterfly collector, tramping around in the fields, taking joy in nature, loving the sheer variety of different types of butterflies (this idyllic picture only being marred by the fact that they were killing animals left and right….). The gentleman naturalist, the Anglican Parson collecting his specimens, seeing the wondrous variety of life forms as proof of Omnipotent glory. Ethology rose out of this tradition where, basically, it was founded by naturalists who were now glorying in the sheer variety of behavior, and who tried to figure out ways to formalize all that great variety. Ethologists loved variety, behaviorists, uniformity. A neuroscientist named Teuber, heavily influenced by ethology, said, ―The experimental
lOMoAR cPSD| 560 91590 Or human smiling. Smiling is a FAP – infants start to do it, with all the appropriate muscles working in coordination, without any teaching. As a great demonstration of that, blind babies start to smile at the same age as other babies do, and with the same movement pattern. An FAP. And where does the plasticity come in? Teaching of context -- you don‘t smile at trees, mannequins, mean people, you do smile at people you like, who are funny, and so on. (This ignores a different type of smiling, namely the subordination smile – subtle differences in muscles involved, and a different type of FAP; work of Paul Ekman at UCSF). Other human expressions have FAP-ish elements as well – the universality of facial expression that denote anger, disgust, contempt, fear, sadness and surprise, the eyebrows raised in greeting.. More examples: A male macaque monkey, raised in isolation in a lab setting, will give a subordinate fear grimace to the projected face of a big male macaque giving a menacing facial gesture. A double FAP – recognizing what the big male‘s face was communicating, and being able to give the appropriate response. And the learning? Obviously, context – who to give what sort of FAP to as a statement of rank. A great example, that vervet monkeys understand the difference between instinct and FAPs. Vervet have different predator alarm calls depending on whether a predator is spotted on the ground (e.g., a leopard), or in the air (e.g., eagle). It is definitely adaptive if you can evolve from, ―Aiii!!!!‖ to ―Aiii!!! Look out below‖ and ―Aiii!!! Look out above.‖ Vervets as young as 4 months old can perform an alarm call that sounds right – it is a FAP. But showing that there is some environmental influence needed, their accuracy isn‘t so hot. Thus, a kid might give an ―Eagle!!!‖ alarm when it spots a pigeon flying. And showing that the adults are ethologists, they don‘t panic until an adult seconds the kid‘s alarm – they understand that the kids make mistakes (work by Dorothy Cheney and Robert Seyfarth of U Pennsylvania). Some recent work shows another version of monkey communicative FAPs shaped by experience. Among Campbell‘s monkeys, fairly young monkeys already have well-developed abilities to make certain social vocalizations – these are FAPs. What they learn are some manners in utilizing these FAPs. Among juveniles, 13% of vocalizations are interrupted by another juvenile; among adults, <1%.
The adaptive value of a behavior As noted, another key ethological question posed by Tinbergen is, What is the behavior good for? Now this is the sort of question asked by sociobiological types all the time, and the way that they come up an answer is to frame it in terms of reproductive success models – Here are basic building blocks of evolution, here seems the most logical way to apply them to making sense of this behavior, lookie, this approach is predictive, and until you can come up with a more predictive model, this counts as an explanation of adaptive value. In contrast, ethologists would get at the issue of adaptive value by actually carrying out experiments in the field.
A classic one from Tinbergen – gull eggs have all sorts of speckled patterns on them. Chicks hatch, egg shells all over the place, some speckled side up, some white Downloaded by angel shirlynne ([email protected]) lOMoAR cPSD| 56091590side up. Tinbergen notes that the mother then systematically turns over all the white ones, so the speckled side is up. FAP – the bird would do it to pieces of speckled cardboard, speckled whatevers, just carrying out this motor performance. And what‘s the adaptive value? In goes Tinbergen with a paintbrush, paints the speckled sides white. And, raptors up in the air, can now spot the egg shell fragments more easily, swoop down and are more likely to predate the chicks. Definite adaptive value there. Von Frisch pioneered this branch of ethology built around communicating, doing his famous studies on the waggle dance of bees. When a forager bee finds some good source of food, they‘d fly back to the hive to try to recruit others to join in bringing back the food. It would be noted that the forager returning with the news does this stereotyped waggle dance – waggling its butt while dancing in this figure- pattern. FAP. But what is its use? Von Frisch translated the dance – the orientation of the dance tells the direction to fly as a function of the sun‘s orientation and gravitational fields; the duration of the dance tells how far away the food is; the intensity of the waggling tells how exciting of a food source it is. But how do you prove it? Put a tray of food (pollen) in a location, let a forager find it, and you then can predict the dance that that will do. But that is just a correlation. Are the bees using the information? Maybe the dance just gets them out of there, and odor takes over. And here is where the ethological style of beautiful, elegant experiments come in – von Frisch would rotate the hive so that the bees lose their gravitational cues, or show a super bright light off to one side of the hive to give them a wrong sense of where the sun is, and they‘d fly to the wrong place, based on this new orientation cue coupled with the information given by the bee (i.e., ―Fly 15 degree left of the sun, for 100 yards and there‘s some food,‖ and the bees fly 100 yards 15 degrees to the left of the axis of the bright light). So what is the adaptive value of this waggle dance FAP? It tells the hive where to find food. A cool, odd example of the adaptive value of a FAP was shown recently by researchers studying crocodile and alligator behavior. They noted that at certain times of year and in certain areas, they would rest on the surface with twigs or branches on their noses (it‘s not clear to me how they‘d get them on their noses, but that‘s another story). What the researchers showed is that this is done when they‘re in the area of bird rookeries, and only at the time of year when birds are building nests. And when the crocs or alligators do this, birds come closer to investigate the swell twig to use for their construction project, thus enhancing the crocs caloric intake. Releasing stimuli: What in the environment triggered the FAP? What sensory stimulus triggered the FAP to occur? This is where Tinbergen‘s dictim about interviewing animal in its own language is never more important, for the simple reason that animals can sense things with acuities and in modalities that we haven‘t a clue about.
the vibration pattern of other termites moving on it, elephants communicating by the vibration in the ground caused by their steps. This ethological framework has allowed some important insights into aspects of behavior. One example concerns the classic work of Harry Harlow. What is it about maternal behavior that causes attachment in offspring? And behaviorists would have a knee-jerk response, which is that infants are attached to their mothers because of the lOMoAR cPSD| 56091590positive reinforcement of nursing. And Harlow‘s critical demonstration was that it was about the comfort, contact, tactile stimulation, not the calories – infant rhesus monkeys, being raised without a mother, could choose between two artificial surrogate mothers. One was ―cold‖—mom made of a chicken wire torso with a Styrofoam head which, nonetheless, supplied calories by way of a bottle of milk protruding from the torso. The other surrogate didn‘t give milk, but was covered in warm terry-cloth. And while a card-carrying behaviorist would be snuggling up to the chicken wire mom, getting positively reinforced by the milk, card-carrying monkeys spent their time on the terry- cloth mom. Translated into ethological terms, Harlow‘s work suggested that FAPs in the mother related to contact, sheltering, and so on, rather than to nursing, were the releasing stimuli for the array of FAPs that constitute attachment in infants. Innate releasing mechanisms and neuroethology So, a releasing stimulus impinges on an organism and, as a result, the FAP pops out the other side. How does that happen? And this is where the behaviorists, in their labs, would say, Who cares?, black box. And, ironically, this is where the ethologists, tromping around in the field in their hiking shoes, would say, Brain, hormones, body, and this is really interesting, but we just don‘t have the tools to study it yet. So they called those intervening steps innate releasing mechanisms. And what used to be this hand waving -- Brain, hormones, cool, but can‘t study it – has become the hottest part of the field, now called neuroethology (where the ―neuro‖ part doesn‘t really mean it only concerns the nervous system, since the term makes room for the endocrine factors as well). The original pioneers in neuroethology (in the 60s, 70s), had to do their work in the lab, and worked mightily to come up with ethologically appropriate settings. One body of work, begun by Mark Konishi of Caltech and Fernando Nottebohm of Rockefeller, tried to figure out how birds learn and produce their songs , what triggers them to sing it. And this was ethology heaven, in terms of the variability among bird species. Some birds sing their song innately; others need to learn theirs. Some come up with a new song each season. Others rip off songs from others (myna birds, for example). In some species, both genders sing, in others, only the male, while the female learns which males are singing which song. And, amid that, differing structures to the motifs and syllables in the songs. And the original work has spawned a massive bird song cottage industry of scientists figuring out, down to the molecular level in many cases, how the brain does this.
Another classic neuroethological body of work came from Donald Pfaff at Rockefeller University concerning the lordosis reflex. Male hamster mounts a female hamster to mate. As a result of the pressure on the back off her flanks, she arches her back into a lordosis reflex. So, tactile pressure as the releasing stimulus; back arch as the FAP. Arched back increasing the likelihood of successful penetration and fertilization as the adaptive value. And, most interestingly, the releasing stimulus triggers the lordosis reflex only if estrogen levels are elevated in the female (i.e., she is ovulating). So Pfaff and crew have done a ton of work sorting out the entire pathway Downloaded by angel shirlynne ([email protected]) lOMoAR cPSD| 56091590– from the tactile receptors in the flanks, up to the brain, back down to the muscles that pull off the reflex, which pieces are estrogen sensitive, what genes estrogen is turning on, and so on. Equivalent neuroethological studies (although they are rarely described as such) are now being done on humans. Show someone a scary face (even so rapidly that they are not conscious of having seen it), and their heart speeds up, their pupils contract, they feel anxious (again, without necessarily being aware of having seen the face). And brain imaging studies focus on the parts of the brain that are activated in response to the releasing stimulus, how that produces the behavioral outcome. Some of the coolest work in neuroethology is now actually being done out in the field , with wild animals. One example comes from the work of John Wingfield of the University of Washington, and Michael Romero of Tufts University (the latter, I note proudly, is an ex-student of mine) with birds. In some species, you have a normal time of the year to mate, but if the weather gets cold prematurely, the birds accelerate the onset of the mating season (logical – ―winter‘s coming early, let‘s get going). So climatic signals as releasing stimuli, changes in behavior (accelerated courtship) as FAP, and thus the question, What‘s going on with reproductive and stress hormones in between? And these guys are actually managing to study this in wild birds. Finally, work with wild baboons done by, well, me, has shown that the neurochemistry of anxiety differs in baboons depending on their social rank, and the social culture of their troop (i.e., how miserable is your life if you‘re low-ranking). Learning As we‘ve already seen with FAPs, ethologists were interested from the start in the role of learning in their view of behavior. To appreciate it, we have to review what the behaviorists thought about the subject (oh great, there he goes, ragging on the behaviorists again), which was the epitome of their dogmatism – reward an organism for doing Behavior X, and it learns to do it more often. Punish for X, learns to do it less. QED. Some of the ways that ethologists thought about learning were far fancier. But sometimes, the type of learning looked pretty conventional. What would be interesting about it was that it would occur in settings where people didn‘t necessarily think learning occurred. Take maternal behavior among primates, for example. Now everyone knows why it is that some female monkey is a competent mother, which is that it is instinctual –
unprecedented behaviors – instead, doing conventional behaviors in very wrong contexts). And this is where the contrast between behaviorist ―a boy is a dog is a rat‖ most dramatically contrasts with, ―interviewing an animal in its own language.‖ You can‘t understand this sort of learning without understanding what the social world of this particular species is about. Downloaded by angel shirlynne ([email protected]) lOMoAR cPSD| 56091590Finally, a remarkably trendy (and legitimate) area of ethology research concerns culture in animals – the non-genetic transmission of behaviors within and across generations. By the hard-nosed rules of anthropology, culture has been demonstrated in a number of other animals. For example, numerous chimp populations across Africa, differ locally in the type and style of tool use, of vocalizations, or the style and meaning of particular gestures. This has been shown in an experimental setting of groups of captive chimps, showing that transmission within a group of a particular style of solving a problem (complete with evidence of conformity, where a chimp that stumbles onto a different way of solving the problem will abandon it in favor of doing it the way that everyone else does it). Or, as a different sort of example, the social milieu of different troops of baboons will differ (in terms of levels of aggression, patterns of socialization), and this social style is passed on to newcomers as they join the troops as adolescents. Cognitive ethology Along with neuroethology, one of the most vibrant areas of the field currently is cognitive ethology, trying to understand thought processes of animals. As was clear when discussing how ethologists approached the issue of the adaptive value of behavior, these folks were major experimentalists, capable of designing a clear-cut, quantitative study. Amid this rigor, ethologists were always dancing around whether, and how, to approach aspects of animal behavior that were much less quantifiable, much less ―scientific‖ in the 9th grade science club kind of way – questions about animal emotion, cognition, and so on. This reflected the ―parson tromping around in the foods, marveling at nature‖ roots of ethology. Not surprisingly, there was a lot of inhibition about overtly doing science in these squishier realms of behavior and cognition, especially if you were, say, coming up for tenure. In 1976, Donald Griffin took this on, with a small book entitled ―The question of animal awareness : Evolutionary continuity of mental experience.‖ It essentially asked, Are animals aware and, if so, can we prove it? For a late 20th century scientist, this was ultra-squishy. Fortunately, not only did Griffin have tenure, but he was one of the most respected ethologists on earth[1], and of the hard-nosed variety. Amid obviously thinking about the subject for many years, he wrote the book very late in his career, as he pretty obviously could care less by then what people thought. And a lot of people in the field very vocally decided that Griffin‘s brain had gone soft and sentimental. Despite that, Griffin‘s book broke a dam, prompting all sorts of studies that are now the core of cognitive ethology, asking questions like: Do animals have self-awareness? According to a standard test used on both humans and non-humans, many other species do – once you make sure you‘re
interviewing an animal in its own language. Do they have Theory of Mind – a recognition that other animals have different information than they do? This appears to be the case for chimps, baboons, as well as lOMoAR cPSD| 56091590corvids (crows, jays, ravens, jackdaws). Depending on your theoretical bent, there are gradations of sophistication of Theory of Mind, and other species aren‘t as fancy about it as we are. Also, there is pretty good evidence that animals (including us) get better at Theory of Mind when they‘re highly motivated (for example, chimps may not demonstrate Theory of Mind in a task requiring that two of them cooperate in getting food, but demonstrate it when they are competing for food). Can they distinguish between intentional and inadvertent behavior? Yes. As one example, captive chimps react differently to a circumstance where a human seems to have disrupted their feeding by accident versus seemingly on purpose (with the chimps being more agitated in the latter case). Do they have flexible cognitive strategies? Most definitely, even including small-brained of beasts as bees—they do not mechanically respond to information (such as in a bee dance) but can distinguish between circumstances where the information makes sense and when it is patently wrong. Do they have numerosity (a sense of numbers)? This seems to be the case with some other primates. Chimps, for example, have been trained to recognize number symbols to the point where they can place trios of them in proper sequence. And as a subtle addition, like human kids, it takes them longer to do this if the numbers are close together. Another example: a rhesus monkey watches you put an interesting object behind a screen. They watch as you put in a second one of that object. You remove the screen revealing either 2 objects or, thanks to spectacular slight of hand, 1 or 3 of the objects. And the monkey will look longer at the cases of 1 or 3 objects than the boring expected 2 object scenario – and that can only happen if there is the recognition that 2 doesn‘t equal 1 or 3. And recent work has suggested that corvids have numerosity as well. (If you spend time reading the cognitive ethology literature, you‘ll note that amid the usual emphasis on primates, corvids are all over the place when it comes to fancy cognition. What‘s up with that? They appear to be really really smart, like in a league not seen with other birds – and related to that, their brain size with respect to body size is off the charts compared to other birds, well in the primate range. Nichola Clayton is the scientist who has most carried the torch for corvid smarts. Do they understand transitivity , and act upon that understanding? Yep. Fish do it, monk-eese do it. Even educated fleas do it. But perhaps, Cole Porter doesn‘t. These cognitive ethology studies often involve really clever, beautiful experiments. Some major themes a) A huge percentage of the time, you can‘t make sense of the behavior of an animal outside the context of its natural setting. B) As a result, behaviors differ tremendously not just by species, but by specific ecosystems or social contexts. C)
