lecture 4 Flashcards
(instrumental learning concepts and theories)
What are modal action patterns
There are behaviours elicited in specific circumstances that require no training
Species specific response patterns
Threshold for eliciting the behaviour varies with physiological state of the animal
Instinctive - but experience can influence their expression
what is the sign stimulus
the stimulus that elicits modal action patterns
What did Tinbergen & Perdeck (1950) show about instinct behaviour in herring chicks
Investigated instinct behaviour by observing the importance of the parent’s bill in herring chick’s pecking behaviour (allows them to ask for food)
Manipulated the shade of the spot on the bill and found that movements and contrast were important but realism and colour weren’t → sign releasing stimuli
What did Baerends et al., 1982 find about sign stimuli
Birds pull in any egg close to nest regardless of how closely it resembles their own eggs
Large eggs elicited the strongest behaviour despite being least like their own and their high ability to recognise this.
Behaviour can be elicited by features of a stimulus that are independent of experience
Several features may contribute additively to the effectiveness of the releasing stimulus e.g colour, speckling and size contributed to egg retrieval
Using this to optimise attractiveness of a stimulus would create a supernormal stimulus more effective that the typical one
what are some human examples of sign stimuli
Aspects of the human face especially baby features act like signs or supernormal stimuli (Glocker et al., 2009)
Baby face: more trustworthy / approachable
Make up : attractiveness
Junk Food - instinctual behaviours
Babinksi reflex - scratch bottom of foot produces splayed toe behaviour → grasping
Developmental change as can still be observed in adults when certain areas are inhibited as a result of alcohol
Most actions rely on learning
what is hypovolemic thirst
when there is low extracellular volume, homeostatic functions drive thirst for water and hunger for salt
symptoms: loss of blood, drop in blood pressure
what is osmotic thirst
when there is high extracellular concentration
respiration increases, concentration of solutes increases
what are the central regulatory factors of hunger
Not the case that there is a single signal from mouth/stomach to brain
Stomach distension similarly only provides some cues to satiety (Janowitz & Grossman, 1949).
Gastrectomized people still feel hungry, Vagotomy still allows eating
The brain (Hypothalamus) is the master regulator and has access to the neural and chemical indicators of the current state of the organism.
Need to learn food → less hunger
what is Miller & Konorski’s 1928 theory of instrumetnal learning
sometimes animals learn to make responses rather than just learn about USs
must do something in order to achieve desired outcome (in pavlovian conditioning the saliva is not a prerequisite of food)
two distinct learning/conditioning mechanism
what is reinforcement instrumetnal conditioning
Reinforcer: increase behaviour
Positive: add appetitive stimulus following correct behaviour
Negative
Escape: remove noxious stimulus following correct behaviour
Active avoidance: behaviour avoids noxious stimulus
what is punishment instrumental conditioning
Punishment: decrease behaviour
Positive: add noxious stimuli following behaviour
Negative: remove appetitive stimulus following behaviour
gambling and variable ration reward frequency Dixon et al, 2014
Comparison of multi-line slot machine performance with single line slot machines
Measure post reinforcement pause (time waited to start again) - proxy for desperation to pay - strength of addiction/ enhanced behavioural responding
20 line machines reduced post reinforcement pause
High risk gamblers experience an enhances sense of competency in 20 line condition
Zoratto et al. (2013) suggest that adolescent rats may be particularly sensitive to reward differences
Do our choices reflect the strenght of possible responses or motivations for possible responses
Herrenstein’s Matching Law (1974) shows that behaviour matches to the reinforcement probabilities (rather than optimal performance)
Animals will engage in behaviour that strives to reduce motivational drives
Outcome can be distant from behaviour (important to recruit short-term motivation)
BUT animals will also engage in behaviours with association with low motivational value to access responses that are associated with higher motivational value
One behaviour can be used as a reinforcer for another behaviour (can’t determine ultimate goal of behaviour)
This means behaviour cannot be used as a metric of motivational states
Secondary reinforcement: high value stimuli or responses can come to be associated with other lower value stimuli and responses (Premac, 1965)
E.g a low probability response is reinforced by access to a high probability response
Therefore linked chains of associations motivate behaviour
what is the role of probability of an outcome for learning
Probability (not frequency) is relevant for strength of CR
Relative frequency and time (Skinner’s schedules) determine the rates of responding
Matching law: animals behaviour correlates with probabilities rather than selecting the best
what is meant by paradoxical choice
choosing to spend more time on actions with lower probability of rewards
this cannot be explained well by reasoning
