Psychology: Learning in sensitive periods

Filial imprintingSong learning in birdsPerceptual learningStimulus relationships

The disruption in conditioning with one element of a compound when it is accompanied by another element that has already been paired with an unconditioned stimulus

Learning experiences are not readily analysed into CSs, responses and reinforcersThese types of learning tend to occur in an early sensitive period in lifeLearned behaviours appear to relatively resistant to change

An improvement in the ease with which discrimination between two stimuli can be acquired as as result of prior exposure to the stimulus

The process by which the following behaviour of an animal tends to become limited to a particular objects as a result of having been exposed to that object, which in nature is usually its mother

Some precocial species

Ensures that young, capable of independent movement, maintain contact with their mother during period where they still rely on her for food, warmth, protection etc

Exposure young chicks to a salient object (usually conspicuous or moving) as a first visual stimulusChick will attempt to approach the stimulusWhen then given a preference test, will choose the pre-exposed stimulus over novel onesPreference increases with duration of pre-exposure

Filial imprinting confined to sensitive period early in lifeOnce an animal is imprinted on an object, it will never forget that object (even if filial responding directed later on another object)Individual (specifically mother figure)/species recognitionIt is a unique type of learning because the imprinting experience cannot be analysed into CS and US/reinforcer

Enables recognition of one's own species as a result of experience with an individual (usually mother) Otherwise adult social and sexual behaviour could be directed to the wrong species when animals are raised by another species

Not for species recognitionBut to establish a recognition of a particular individual within the species, usually the mother

A form of Pavlovian conditioning

Salient features of the object (colour, movement) act as USUnique stationary features (shape) function as CS so that animal approaches the object

Hoffman's experiment measuring approach to a stationary inconspicuous stimulus as CS and the same stimulus but moving (US). Showed moving presentation paired the CS features with reinforcement induced by US movement to yield approach to the object as a response

Sensitive period is not for learning per seBut the time period when the imprinting stimulus acts as an effective reinforcer

Bolhuis and de VosImprinting subject to blockingChicks exposed to YY cylinders or YR in first stageControl group exposed to RRChicks exposed to YB cylinders in second stageIf imprinting can be blocked, pretraining to Y should block learning about B in stage 2Confirmed: Chicks spent less time next to B when presented alone compared to control group

Long, elaborate vocalisationsTypically produced by males in the breeding season

Predispositions: direct the chick's attention to certain kinds of objectsLearning: enables the chick to recognise an individual and establishes it as a positive reinforce

ParrotsHummingbirdsSongbirds (Passerines) (which have the oscines and suboscines within them)

Males produce song to defend territory from rival malesMales produce song to attract potential mates

KrebsMale great tits removed from territories and replaced with speakers playing great tit songs or white noise or silenceSong playback territories were not reoccupied where as others were

Catchpole - Sedge WarblersMales with larger repertoires paired earlier in season than those with simpler songsFemales display more when exposed to more complex male song recordings

The bird initially has a crude template on which to base its songIn a memorisation/sensory phase, this template is then matched to a song that is heardIn a subsequent motor phase, testosterone stimulates the bird to produce the songAn auditory feedback loop occurs where the bird hears its own song and matches it to the template has learned/committed to memoryThis phase can take a long time and the two phases are separated by some period of time

In an early sensitive period of their life

Produces a song that contains both features of its species-typical sub-song and that of the modelBecause the song is produced by combining predispositions and templates which they hear

Birds tutored with tape recording of multiple species choose to imitate conspecific songs

Exposure to restricted range of stimuli in a sensitive period produces long lasting effectsOnce learned, memories unlikely to be updated/replacedTwo main sub-processes: predispositions and learning systemsMotor and sensory componentsBehaviours are restricted to only some species (though different for each)

Predisposition to attend a suitable class of stimuli (object to follow, sounds to mimic)A learning system (allows recognition of individuals or learning song of a tutor)

Motor component is approach behaviour Sensory component/phase is the chick learning to recognise individualsThese components occur con-currently/go hand in hand

Animal must learn about specific stimuli for its species and the environment in which it livesTo ensure this happens (and for correct stimuli) restricting learning process to a period when animal is guaranteed to be in the presence of these stimuliLimit sensitivity to those stimuli only relevant to the specific species