1 THE MODIFICATION OF INSTINCTIVE BEHAVIOR 2 Elicited

1 THE MODIFICATION OF INSTINCTIVE BEHAVIOR

2 Elicited or Unconditioned Behavior Occurs without past experience Modifiable with experience (examples: habituation and sensitization

3

Some Types of Elicited Behaviour 4 An eliciting or unconditioned stimulus elicits a response without any prior learning Types of Elicited Behaviour Simple Reflex Orienting Reflex Taxis (taxes) Kinesis (kineses) Fixed/Modal Action Patterns

FAPs/MAPs 5 Sequence of behaviors directed at the eliciting (sign or releasing) stimulus Sometimes requires underlying drive (hydraulic/energy model) Vigor of response depends on how closely the sign stimulus corresponds to the ideal stimulus (e. g. , cute baby) Small (non-ideal), Normal (ideal), Supernormal (exaggerated ideal)

Releasing Stimuli 6

Supernormal stimulus 7 An accurate 3 -dimensional model of a herring gull's head (a), and a 'supernormal' bill (b).

Supernormal stimulus 8

Supernormal stimulus? 9 versus 1950 s 1990 s

Lorenz – Tinbergen Model 10

Energy Model 11 Action-specific energy: an internal force that motivates a specific action Builds up “internal pressure” that motivates animal to behave in a certain way IRM (innate releasing mechanism) releases stored energy Appetitive behavior: instinctive or learned response motivated by action-specific energy and attracted to a sign stimulus

Environmental Release 12 Sign stimuli are environmental stimuli Some are simple Others are quite complex Likelihood of eliciting a FAP depends on Accumulated level of action-specific energy Intensity of the sign stimulus The relationship is inverse The greater the level of accumulated energy, the weaker the sign stimulus that can release the FAP

Conflicting Motives 13 When two incompatible sign stimuli are encountered, the response may be different from the FAP from either acting alone A third instinct system, different from either of the two conflicting systems, is activated Displacement: in a conflict situation, the occurrence of a behavior unrelated to that conflict

Habituation 14 a simple type of learning which is shown by a change in elicited behaviour over trials defined as a reduction in responsiveness (frequency, magnitude) over successive trials sometimes short-lasting and sometimes long lasting

15 Habituation-One Type of Modifiability Eric Kandel and Aplysia

Kandel`s Experiments 16 Touch Siphon Gill Withdrawal

Habituation 17 gill withdrawal touch

Forms of Habituation 18 Short-Term lasts only a few minutes best if stimulus applied at short intervals (2 -s) Long-Term lasts weeks best if stimulus applied at longer intervals (30 -s)

Simplified Circuit 19

Mechanism of Short-term? 20 decreases in synaptic transmission loss of skin sensitivity decrease in motor synapse fatigue

Not Muscle Fatigue 21 Spontaneous Evoked Pinsker et al. , (1970) Science 167: 1740

Mechanism of Short-term? 22 decreases in synaptic transmission loss of skin sensitivity decrease in motor synapse fatigue

Not Motor Synapse 23 Before skin SN After electrical MN record gill Kupfermann et al. , (1970) Science 167: 1743

Mechanism of Short-term? 24 decreases in synaptic transmission loss of skin sensitivity decrease in motor synapse fatigue

Skin Sensitivity? 25 touch skin SN MN record MN activity to assay habituation Trials 1 to 8 gill Kupfermann et al. , (1970) Science 167: 1743

Not Skin Sensitivity 26 26 touch skin SN block MN record MN activity to assay habituation Trials 10 -20 gill Kupfermann et al. , (1970) Science 167: 1743

What’s the Mechanism of Short-ter 27 decreases in synaptic transmission loss of skin sensitivity decrease in motor synapse fatigue

28 Mechanism: Short-term Habituation Decrease in neurotran released at the synap both the motor neuron interneuron!

29 Mechanism of Long-Term Habituation Change in the number of synapses!

30 Properties of Habituated Responses 1. Spontaneous Recovery 2. Dishabituation 3. Generalization

Spontaneous Recovery 31 Hi Response Stimulus Time Passes Lo Number of Presentations

Dishabituation 32 Hi Response Stimulus Novel Event (no time passes) Dishabituation Lo Number of Presentations

Generalization 33

34 Sensitization- Another Type of Modifiability enhanced response to a “benign” stimulus after exposure to a “noxious” one (most common) for example, startle enhanced response after repeated presentations of a “not so benign” stimulus (less common)

35 Rat Startle

Human Startle 36

37 Thompson/Groves Dual Process Theory Competition between two separate processes 1. S-R System: Habituation 2. State System: Sensitization

39 Conditions Favouring Habituation 1. 2. 3. 4. 5. 6. 7. Calm organism Shorter interstimulus intervals Less variable interstimulus intervals Low intensity Less complexity More trials More Stimulus Specificity

Interstimulus Interval 40

Complexity 41 Looking Time Trials

42 One example of habituation is when animals gradually eat more of a novel food after initial ingestional neophobia Ingestional neophobia: the avoidance of novel foods Habituation of the neophobic response can lead to increased consumption of novel foods

43 Animals can also show an increased neophobic response If an animal is ill when it ingests a novel food, it may avoid the food in the future The greater neophobic response when animals are ill is due to sensitization process

44 Experience can also influence the properties of a reward Homeostasis has traditionally been considered responsible for either increased or decreased effectiveness of a reward Decreased effectiveness due to satiation Increased effectiveness due to deprivation

45 However, it appears that habituation and sensitization can also influence Habituation leads to decreased effectiveness Sensitization leads to increased effectiveness Habituation and sensitization can explain changes in reward effectiveness that cannot be explained by homeostasis

46 Habituation is the process that filters out external stimuli of little relevance by raising the sensory threshold to those stimuli Sensitization decreases sensory thresholds to potentially relevant external events

47 Thus, habituation and sensitization are processes that optimize an animal’s likelihood of detecting significant external events

The Dishabituation Process 48 Dual process theory states that the arousing effect of the sensitizing stimulus causes the habituated response to return In the absence of the sensitizing stimulus, habituation remains

The Nature of Dishabituation 49 Pavlov suggested that dishabituation is a reversal of habituation Thus, the dishabituation of the withdrawal response in Aplysia would be a return to the prehabituation level of neurotransmitter released from the sensory neuron

50 In contrast, Grether proposed that dishabituation results from a process similar to sensitization superimposed on habituation In Aplysia, this would suggest two processes Decreased neurotransmitter release as a result of habituation Increased neurotransmitter release produced as a result of a sensitization experience

51 Most research supports Grether’s view Habituation and sensitization are simultaneously independent and interdependent processes The interdependence of habituation and sensitization has adaptive value Habituation allows us to ignore unimportant stimuli Sensitization reinstates the response in case those stimuli now have become important

Opponent-Process Theory 52 Opponent process theory: theory that an event produces an initial instinctive affective response, which is followed by an opposite affective response

Our Initial Reaction 53 All experiences, both biological and psychological, produce an initial affective reaction A state: the initial affective reaction to an environmental stimulus in opponent process theory The strength of the A state is influenced by the intensity of the experience The more intense, the stronger the A state

54 The A state arouses a second affective reaction B state: the opposite affective response that is elicited by the initial affective reaction in opponent process theory The B state is opposite the A state

55 Initially, the B state is less intense than the A state The B state also intensifies more slowly than the A state After an event has terminated, the B state diminishes more slowly than the A state The opponent affective response will be experienced only when the event ends

56 Intensification of the Opponent B State Repeated experience with a certain event often increases the strength of the opponent B state This reduces the magnitude of the affective reaction experienced during the event Thus, the strengthening of the opponent B state may well be responsible for the development of tolerance

57 Tolerance: reduced reactivity to an event with repeated experience When the event ends, an intense opponent affective response is experienced Withdrawal: an increase in the intensity of the effective opponent B state following the termination of an event

The Addictive Process

The Addictive Process 59 Opponent process theory offers an explanation for the development of addiction Addictive behavior is a coping response to an aversive opponent B state Addictive behavior is an example of behavior motivated to terminate (or prevent) the unpleasant withdrawal state Parachute jumpers – create a B state in order to feel the A state.