A.4 Innate and Learned Behavior

Understandings Innate behavior is inherited from parents and so develops independently of the environment Autonomic and involuntary responses are referred to as reflexes Reflex arcs comprise the neurons that mediate reflexes Reflex conditioning involves forming new associations Learned behavior develops as a result of experience Imprinting is learning at a particular life stage and is independent of the consequences of behavior Operant conditioning is a form of learning that consists of trial and error experiences Learning is the acquisition of skill or knowledge Memory is the process of encoding, storing, and accessing information Application Withdrawal reflex of the hand from a painful stimulus Pavlov’s experiments into reflex conditioning in dogs The role of inheritance and learning in the development of birdsong Skill Analysis of data from invertebrate behavior experiments in terms of the effect on chances of survival and reproduction Drawing and labelling a diagram of a reflex arc for the pain withdrawal reflex.

Innate Behavior Develops independently of environmental Spider spins a web correctly, first time No trail and error learning Controlled by genes and inherited by parents Behaviors ensure survival of animal Types of behaviors Wasps building nest Termites build mounds Birds song Sucking in human infants Courtship

Study simple invertebrate – innate behavior measure as response to environmental stimuli Taxis Directed response to stimulus Body toward stimulus – positive response Body away from stimulus – negative response Chemotaxis – response to chemicals pH, concentration of dissolved drugs, foods, pesticides Phototaxis – response to light Different wavelengths, light intensities, types of light bulbs Gravitaxis – response to gravity Upside down container, slow-spinning turntable Rheotaxis – response to water current Move with or against current Thigmotaxis – response to touch

Types of invertebrates Planaria – flatworm Quite active, move by contraction of muscle fibers Simple nervous systems Two eye spots – photoreceptors stimulated by light (negative phototaxic) Chemoreceptors – response to certain chemicals (positive chemotaxic) Studies: different wavelengths, food substances in water, temperature gradient, concentrations of pesticides

Euglena – single-celled protist Flagellum for propulsion Eyespot – stimulate by light Photosynthetic – positive phototaxic Study: different wavelengths of light

Kinesis Movement in response to non-directional stimulus Humidity Does not move away from or toward stimulus, but erratically till new spot found “comfort zone” – movement slows Orthokinesis Organism moves slowly/rapidly (changes speed) in response to stimulus Klinokinesis Turns slowly/rapidly in response to stimulus Isopods (terrestrial crustaceans) Live in damp places – have gills, not lungs Kinesis  humidity Moist, slow movement Dry, rapid movement Species for study: woodlice (Porcellio scaber, Armadillidium vulgare)

Reflexes Controlled by autonomic nervous system Pain Reflex Arc

Reflex conditioning Classical conditioning used to modify reflex response Subjects responds in new way Blinking (reflex response) Unconditioned stimulus (UCS): air puff on eyes Unconditioned response (UCR): eye-blink response Train eye to elicit reflex response with new, neutral stimulus (NS) NS (musical notes) introduced, subject does not blink Period of training: musical note sounded immediately before wave of hand Subject learns to eye-blink to musical note – conditioned stimulus (CS), conditioned response (CR)

Ivan Pavlov designed classical training response Subjects: dogs UCS: food in mouth  UCR: salivation NS: ringing of bell Rang bell just before dog tasted food CS: ring bell  CR: salivate Dog learned to salivate to NS alone

Learned Behavior New knowledge/skills formed or modifying existing knowledge Measured by performance Learning explained as change in performance Stored in nervous system as memory Behavior output is not always easily seen = measuring learning difficult Innate Behavior Learned Behavior Develops independently of the environmental context Dependent on the environmental context of the animal for development Controlled by genes Not controlled by genes Inherited from parents Not inherited from parents Developed by natural selection Develops by response to an environmental stimulus Increases chance of survival and reproduction May or may not increase change of survival and reproduction

Imprinting Rapid learning process by which a young animal develops an attraction and recognition of another moving object Initiated within a critical period – 13-16 hours for goslings Goslings will follow first moving object (inanimate or living) Conclusion: Imprinting is a behavior that occurs regardless of consequence

Operant Conditioning Original behavior is performed spontaneously during exploration of environment Experimenter wishes to change the likelihood of this behavior (operant) being performed Animal brings about a change in its environment by performing a particular pattern of behavior Skinner Box No interference from experimenter Change: food released by lever  learn to repeatedly press lever for food

Innate and Learned Behavior through Bird song Well studied example of animal behavior Species-specific songs in birds – inherited Birds can learn to improve song  inherited and learned behaviors Syrinx – vocal organ in birds Bony structure at bottom of trachea Force air past membrane in syrinx  vibrates  sound Control: Pitch – altering tension in membranes Volume – altering air flow

Learning of Birdsong Memorization phase Crude template Template matched to song heard by adults Duration 100 days: if hear no song in time, does not move to motor phase  sensitive period Exact template Motor phase Song output Hears own song Song matched to template Sings more or less accurate copy of song heard

Accessing Visual: converting information into mental pictures Elaborative: relating new information to old Acoustic: sound (spoken language) Sensation: Touch, smells, tastes Semantic: sensory input in a context (pneumonic) Occurs at neuron level due to synaptic signals More signals sent  stronger neuron  more likely to retain information Forgotten information  synaptic connection is weakened due to lack of use

Retrieval Short-term memory (STM): small amount of information Actively using information Retrieved in sequence Long-memory (STM): physical change in neural network Continual use strengthens neuron connections Accessing Recognition: association of physical object or event Compare present information with memory Recall: fact, object, event not currently present Actively reconstruct memory requires activation of those neurons involved