Developmentof Behavior Chapter 11
The development of behavior is regulated by the genes inherited vs The development of behavior is determined by the environment andlife experiences. (The old Reductionism vs Behaviorism) Nature/ Nurture Misconception Konrad Lorenz
An 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 = parasitic European species; Cowbirds = American parasite Instinct
A change in behavior due to previous experience. Within one life time. Ex. Toad learns to avoid centipede Learning
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.
The Interactive Theory of Development • Genes are essential for all aspects of behavior. • body structure • Nervous system development • Hormone differences • The environment can influence what and when genes are expressed • Sex hormones influence gene expression involved in body and brain development • Social interactions can change gene expression
Peking duck example: • Spontaneous motility - does not respond to sensory stimulation. >>> 3-4 days • Internally stimulated motility: movements caused by fluid and other changes within the body >>>aimless, jerky and convulsive • Evoked 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 tactile stimulation (touch) around the mouth. 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. Genes regulate nervous System Development
White-crowned sparrow (Zonotrichialeucophrys): Interactive Theory Applied to Song Learning
The development of a song in the white-crown sparrow involves the interactions among • Genetic information (neurons in midbrain respond selectively to species specific song) • Hormonal signals in turn influence gene expression and brain development • Development of the nervous system (modifications of neurons in midbrain during critical or sensitive period) • Acoustical stimulation. • live tutors extend sensitive phase more than tapes • hearing own song is important
The Interactive Theory – honey bee example • Microarray evidence for gene expression changes as bee ages • Gene expression is influenced by social environment • Absence of nurses or foragers • Addition of young or old bees to the colony
Internal environment influences Gene Expression - Sexual maturity in vertebrates. Changes involve anatomical and physiological changes, as well as behavioral changes. Hormones influence gene expression.
Some species, development results in two alternative phenotypes (polyphenism) with distinctive behavior. 1. Food – induced. Ex. honeybee queens versus workers; Migratory locust 2. Socially-induced. Ex. Nurse vs foraging in honey bees; territorial behavior in cichlid fish (Haplochromusburtoni); cannibal and non-cannibal forms of the tiger salamander 3. Predator-induced. Ex. aphid soldiers w/ large defensive legs (may be population density, too) Developmental Switch Mechanisms
development of behavior can be classified into a set of 3 general categories along a continuum • Restricted development • Semi-restricted development • Flexible development
a. Sign stimulus - An external signal that elicits specific responses from conspecifics b. 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. Restricted Development
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 inappropriate The nature of fixed action patterns can lead to inappropriate behavior because the animal is paying attention to a limited amount of information.
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.
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
Second example: Rove beetles (Staphalinidae) and Formica ants 1. gland secretions trigger care and feeding 2. In the winter, Formica do not raise brood, but Myrmica ants do Therefore they change nests in late fall using chemical signals to appease aggressive behavior and trigger "adoption".
Instinctive behaviors: Most species sleep, forage, find mates, orient, court, lay eggs, provide minimal care for young, respond to predators, without any learning opportunity May not be FAP, but often behavior is triggered by specific cues.
Behavior that is modified in a very constrained way as a result of experience while performing the behavior the first time. Semi-restricted Development
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:
Hess: Imprinting reversal in mallard duck Imprinting 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 duck a. Reversal to a duck could happen, but not from duck to human Imprinting – further work
Curio: Mobbing behavior in blackbird • Experimental set up: Related research Honeycreeper as test
Language acquisition in humans is somewhat the same as in white-crowned sparrows a. 3000 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. Language development
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 Human infants can discriminate speech sounds
100 % Subjects able to discriminate 2 t/T sounds 50 Hindi Infants English Speak. In Engl. Speak. Adults homes Adults 6-8 mon. Janet Werker 1980's - Baby's perception of sounds - 2 Hindi sounds t and T == not used in English 85 10
1. Selective attention by young to similar to speech sounds of species-specific syllables 2. Critical period for storage of song some indication – must hear spoken language early in life to acquire speech (babbling - comparing sounds against those heard, if can't hear sound, will not develop speech easily or at all) Parallels in development between humans and sparrows - Summary
3. Relatively unstructured subsong same babbling 4. Full development of song depends same on hearing self-generated sounds 5. Population dialects arise through same imitation 6. Once full song is acquired, it is language acquisition resistant to modification skill declines with age Parallels in development between humans and sparrows - Summary
Where behavior is modified by experience = Learning is a major factor Flexible development
1. Habituation - the persistent waning of a response from repeated stimulus presentations. 2. Imprinting - already covered earlier 3. Spatial learning – using learned patterns of features to move around in one’s environment 4. AssociativeLearning - acquired connection between a stimulus and a response that did not exist before. Habit formation a. classical conditioning b. operant conditioning 5. 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 Types of Learning
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 reward Black – no reward Blue – regular reward Avg. # Errors Days
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 bell • Training - repeated sequence: bell, food in bowl • Results: no salivation with bell, learned to salivate with bell • Dog has learned to associate the bell with food coming. Associative Learning - Classical 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 reinforcement Ex. 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) Associative Learning - Operant Conditioning
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 behavior Limitations – 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. languages
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 sequence Cognitive Learning – con’t chimpanzee
Social Learning • Jane Goodall documented social learning in chimpanzees • Rice foraging among Japan’s snow monkeys • Migration paths in some birds like whooping cranes – need to fly with adults to overwintering grounds
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 Adaptive Aspects of Restricted Development
Pecked at all except those with alternating red and yellow rings No. Pecks 0 89 60 79 – 15% striped end 90 – 47% striped end
Birds that have an instinctive dislike for that particular pattern will have a far greater chance of surviving and passing on their genes. # birds Aversion Strong selection on young birds for an aversion to color pattern; life expectancy of a bird that pecks at a coral snake is short Directional selection
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) Adaptive Aspects of Restricted Development – con’t
1. Not flexible - behavior can not change and improve rapidly; evolution takes many generations 2. As shown earlier, innate patterns can be taken advantage of by animals which "break" the code - rove beetles and ants 3. As shown earlier, innate patterns can lead to inappropriate behavior Non-adaptive Aspects to Restricted Development