2 Nature/ Nurture Misconception The development of behavior is regulated by the genes inherited vsThe development of behavior is determined by the environment and life experiences.(The old Reductionism vs Behaviorism)Konrad LorenzKonrad Lorenz
3 InstinctAn action that is performed in a functional manner the first time an animal of certain age and motivational state encounters the appropriate environmental cue for the behavior. The performance of an instinct can only change over generations as individuals with different first-time responses are selected for or against.Ex. Cuckoo bird = parasiticEuropean species;Cowbirds = American parasite
4 LearningA change in behavior due to previous experience. Within one life time.Ex. Toad learns to avoid centipede
5 Even though these are distinct – neither is totally genetic or environmental 1. Cuckoo bird instinctually tries to push host egg out of nest, but practice is required before the bird is actually successful.2. Toad has learned not to feed on centipede, but the basis for the feeding response (body orientation, lunge) all result in part from the genes the toad has. In addition, in most animals, certain things are much easier to learn than others.
6 The Interactive Theory of Development Genes are essential for all aspects of behavior.body structureNervous system developmentHormone differencesThe environment can influence what and when genes are expressedSex hormones influence gene expression involved in body and brain developmentSocial interactions can change gene expression
7 Genes regulate nervous System Development Peking duck example:Spontaneous motility - does not respond to sensory stimulation. >>> 3-4 daysInternally stimulated motility: movements caused by fluid and other changes within the body >>>aimless, jerky and convulsiveEvoked motility: movements which are initiated as a result of stimulation of the sensory systems from the external environment. >>> 7 days - chicks will first respond to tactilestimulation (touch) around the mouth.Gottlieb studied embryonic Peking duck chicks (1971)
8 Genes regulate nervous System Development Integrated movements begin at 17 days- eventually move body into a hatching position and lead to piping and the act of hatching at about day 20.Peking duck embryos respond selectively to the maternal call of their own species at about 5 days before hatching. This ability is not dependent on prior exposure to either their own vocalizations in the egg or those of their siblings.
9 Interactive Theory Applied to Song Learning White-crowned sparrow (Zonotrichia leucophrys):
10 Acoustical stimulation. The development of a song in the white-crown sparrow involves the interactions amongGenetic information (neurons in midbrain respond selectively to species specific song)Hormonal signals in turn influence gene expression and brain developmentDevelopment of the nervous system (modifications of neurons in midbrain during critical or sensitive period)Acoustical stimulation.live tutors extend sensitive phase more than tapeshearing own song is important
12 The Interactive Theory – honey bee example Microarray evidence for gene expression changes as bee agesGene expression is influenced by social environmentAbsence of nurses or foragersAddition of young or old bees to the colony
13 Internal environment influences Gene Expression - Sexual maturity in vertebrates. Changes involve anatomical and physiological changes, as well as behavioral changes. Hormones influence gene expression.
14 Developmental Switch Mechanisms Some species, development results in two alternative phenotypes (polyphenism) with distinctive behavior.1. Food – induced. Ex. honeybee queens versus workers; Migratory locust2. Socially-induced. Ex. Nurse vs foraging in honey bees; territorial behavior in cichlid fish (Haplochromus burtoni); cannibal and non-cannibal forms of the tiger salamander3. Predator-induced. Ex. aphid soldiers w/ large defensive legs (may be population density, too)Honey bees – royal jellyCichlids - dominanceTiger salamander – pop density and size differentialAphids – all clones – no genetic differences
16 development of behavior can be classified into a set of 3 general categories along a continuum Restricted developmentSemi-restricted developmentFlexible development
17 Restricted Development a. Sign stimulus - An external signal that elicits specific responses from conspecificsb. Innate releasing mechanism - A neural process, triggered by the sign stimulus that preprograms an animal for receiving the sign stimulus and mediates a specific behavioral response (FAP)c. Fixed action patterns – (FAP) An innate stereotypic behavioral response to a specific sign stimulus, that is independent of immediate control, genetically encoded, and independent of individual learning.
19 Ex. Male blackbird can be induced to copulate (FAP) w/ feathers +tail of a female. Raised tail = sign stimulus for copulatory behavior.Once the FAP is begun, it is completed even though inappropriateThe nature of fixed action patterns can lead to inappropriate behavior because the animal is paying attention to a limited amount of information.
20 Ex. Parent birds of many species will respond to the shiny whitish fecal sac produced by a baby bird by picking up the sac and throwing it away. If band on baby bird's leg is white, baby may be thrown away even though it is crying and giving distress signals.
21 Animals which can break the code of the sign stimulus, can often take advantage of a fixed action pattern:Ex. Cow or cuckoo young are super beggars
23 Second example:Rove beetles (Staphalinidae) and Formica ants1. gland secretions trigger care and feeding2. In the winter, Formica do not raise brood, but Myrmica ants doTherefore they change nests in late fall using chemical signals to appease aggressive behavior and trigger "adoption".
24 May not be FAP, but often behavior is triggered by specific cues. Instinctive behaviors: Most species sleep, forage, find mates, orient, court, lay eggs, provide minimal care for young, respond to predators, without any learning opportunityMay not be FAP, but often behavior is triggered by specific cues.Butterflies lay eggs on specific food plantPacific Palolo worm release eggs and sperm 1/yr with a full moon in late autumn posterior ½ moves to surface and gametes released. May have acres of fertilized eggs floating on the surface the next day. 24 hr – ciliated larva that sinks to the bottom – metamophoses into a polychaete worm
25 Semi-restricted Development Behavior that is modified in a very constrained way as a result of experience while performing the behavior the first time.
26 Imprinting:Hand-raised young ducks followed Konrad Lorenz even over other humans; with maturity, males courted humans If a young duck is not exposed to any type of object during the first week of life, the ducks will not imprint = critical period Nervous system is primed to learn the appearance and or odor of their parent Once learned, it is usually irreversible.Imprinting – learning that occurs during a critical period and is then irreversible.
27 Imprinting – further work Hess: Imprinting reversal in mallard duckImprinting to real parents > human imprinting. Hess worked found that it took 20 hr to imprint to a human, but only 1.5 hr to a ducka. Reversal to a duck could happen, but not from duck to human
28 Related research Curio: Mobbing behavior in blackbird Experimental set up:Honeycreeperas test
30 Language developmentLanguage acquisition in humans is somewhat the same as in white-crowned sparrows a languages, total of 40 speech sounds ("phones"); all languages have grammatical rules for the construction of sentences and use a subset of phones. b. Human infants have brains primed to learn a language. Studies (Janet Werker) have shown that 6 wk old infants will respond to certain sounds such as ba or pa other basic sounds; if repeated - lose interest.
31 Human infants can discriminate speech sounds c. There are set stages that all humans go through as they learn to speak: babble, one word, two word sentences, telegraphic speech: noun (no plurals), verb (without tenses), bare essentials, full speech
32 Janet Werker 1980's - Baby's perception of sounds - 2 Hindi sounds t and T == not used in English 100 % Subjects able to discriminate 2 t/T sounds 50 Hindi Infants English Speak. In Engl. Speak. Adults homes Adults 6-8 mon.8510
33 Parallels in development between humans and sparrows - Summary 1. Selective attention by young to similar to speech sounds of species-specificsyllables2. Critical period for storage of song some indication –must hear spokenlanguage early inlife to acquire speech(babbling - comparing sounds against those heard, if can't hear sound, will not develop speech easily or at all)
34 Parallels in development between humans and sparrows - Summary 3. Relatively unstructured subsong same babbling4. Full development of song depends sameon hearing self-generated sounds5. Population dialects arise through sameimitation6. Once full song is acquired, it is language acquisitionresistant to modification skill declines with age
35 Flexible developmentWhere behavior is modified by experience = Learning is a major factor
36 Types of Learning1. Habituation - the persistent waning of a response from repeated stimulus presentations.2. Imprinting - already covered earlier3. Spatial learning – using learned patterns of features to move around in one’s environment4. Associative Learning - acquired connection between a stimulus and a response that did not exist before. Habit formationa. classical conditioningb. operant conditioning5. Cognitive Learning - problem solving - in humans and higher apes, other mammals, some invertebrates such as octopus learning can involve perception and understanding.6. Social Learning – learn by watching others and mimicking it
37 Spatial learning - learning a maze - an internal learning of a pattern - again not simply a stimulus response Learning can be latent - when animal shows no sign of having learned anything at the time of the teaching experience Ex. Maze running in rats: one group rewarded; one group no reward, one group allowed time in a maze to wander around - no rewards until day ll. Then tested in ability to learn to run maze; rats with previous exposure learned to run maze faster - learned without reward.Red – day 11 rewardBlack – no rewardBlue – regular rewardAvg.#ErrorsDays
38 Associative Learning - Classical Conditioning Ex. Ivan Pavlov studying digestion in dogs, noticed that the saliva in the mouth of the dog would begin to flow with the sight of food. Dog set up - monitor saliva flow, food dispensed to bowl by machine, hear bellTraining - repeated sequence: bell, food in bowl Results: no salivation with bell, learned to salivate with bellDog has learned to associate the bell with food coming.
39 Associative Learning - Operant Conditioning In this case, the response is not already in place (such as salivation to food) - behavior is shaped into a new form with positive or negative reinforcementEx. Teaching a dog to roll over - get dog to do some unusual act and reinforce the behavior in response to a command by giving a biscuit or hug (positive reinforcement) Ex. B. F. Skinner - worked with behavior which was not in direct response to a stimulus (salivation to food)= operant - the animal operates on the environment to produce some effect (not just responding to environment)
41 1. Can not teach any behavior to any animal - genetic restraints. Ex. Priscilla, the Fastidious Pig" - turned on TV, ate breakfast at a table, picked up dirty clothes and put them in a hamper, ran a vacuum cleaner over the floor, picked out her favorite food, took part in a quiz program answering questions from the audience. (not special- new pig trained every 3-5 months)Superstitious behavior - if blow on dice and win at gambling - reinforced behaviorLimitations –1. Can not teach any behavior to any animal - genetic restraints.2. Even within the repertoire of an animal, certain behaviors much easier to teach than others 3. Ability to learn changes with age –e.g. languagesSkinner students – went into businesss
43 Cognitive Learning – con’t Some situations, learning is not stimulus-response Insight learning = comes from an internal visualizing of the problem and coming up with a solution without trial and error Ex. Wolfgang Kohler - chimpanzee - sticks and fruit bananas Two step solution done suddenly without practice in one clear sequencechimpanzee
44 Social Learning Jane Goodall documented social learning in chimpanzees Rice foraging among Japan’s snow monkeysMigration paths in some birds like whooping cranes – need to fly with adults to overwintering groundsRecent item in news – ultralight plane pilot was paid this year as he was leading human reared whooping cranes to overwintering grounds in Florida. The pay means he’s a commercial pilot and he didn’t have a commercial pilot’s license. The FAA grounded him until they could review the situation, but released him jan 11.
45 Adaptive Aspects of Restricted Development In some situations, the time necessary to learn something may cost that animal its life or opportunity to reproduce Ex. birds and predatory snakes, the time required to learn fear of a predator may cost a life- Susan Smith studied Motmot and coral snakes 1. Motmots eat snakes and lizards - normally attracted by long, thin shape 2. Coral snakes are poisonous with a bright red, yellow and black bands 3. Hand reared birds; allowed to peck at painted wooden models
46 Pecked at all except those with alternating red and yellow rings No. Pecks896079 – 15% striped end90 – 47% striped end
47 Strong selection on young birds for an aversion to color pattern; life expectancy of a bird that pecks at a coral snake is shortBirds that have an instinctive dislike for that particular pattern will have a far greater chance of surviving and passing on their genes. # birds AversionDirectionalselection
48 Adaptive Aspects of Restricted Development – con’t Short lived animals such as an insect or spider: There isn't time or expose to other adults necessary for learning a courtship song or ritual. For successful reproduction, courtship song or ritual has to be innate.No time, opportunity, reduced cost (nerve structure)
49 Non-adaptive Aspects to Restricted Development 1. Not flexible - behavior can not change and improve rapidly; evolution takes many generations2. As shown earlier, innate patterns can be taken advantage of by animals which "break" the code - rove beetles and ants3. As shown earlier, innate patterns can lead to inappropriate behavior
51 Adaptive Value of Learning: 1.Change in behavior can be within one lifetime 2. Information can be processed for better decisions: White-crown sparrow - Females prefer to mate with males that sing with the dialect of their natal home. The selective advantage may be that in this way the female is selecting a male with a proven ability to survive in that location.
52 Non-adaptive Aspects of Learning Cost to learning = neural complexity, long developmental time, and long dependency periodAnimal mimicry - takes advantage of learningViceroy to right