Chapter 5: PerceptionI. Seeing, Thinking, and Doing in InfancyA. Definitions1) Sensationa) Sensory processing of information via organs of sensation (ears, eyes, nose, etc.)2) Perceptiona) Organization and analyzation of inputted sensory informationB. Vision1) Preferential-looking techniquea) Research method that times how long an infant looks at an object2) Visual Acuitya) The clarity of infants’ visionb) Very low at birth (20/120)c) Much better at 8 months of age (20/30)d) Contrast sensitivity(i) Infants have difficulty distinguishing between two non-contrasting colors(ii) Caused by immaturity of cones in infants’ eyes- Cones enable color vision- Color vision is developed by 2-3 monthse) Acuity is fully developed by 6 years of agef) Tested using preferential looking3) Visual Scanninga) Sticky perception(i) Newborns have trouble moving their eyes to specific spotb) Newborns have great difficulty controlling eye movements (i) Can begin to visually track objects at 3 months of age(ii) Aka smooth pursuitc) Perception of faces(i) Newborns tend to look at the outline and high contrast features of a face or object as opposed to the object as a whole(ii) By two months, infants begin looking at more internal parts of objects (color vision is enabled, allowing for perception of low-contrast areas)(iii) Predetermined ability to distinguish faces over other objects are innate, butdevelopment of ability is controlled by experience(iv)Newborns prefer mom’s face over an unfamiliar woman’s(v) Infants prefer faces of caregiver’s gender(vi)Infants prefer attractive faces(vii) Other Race Effect (ORE)- More difficult to distinguish faces of races one is not a part of or exposed to- 9-month-olds experience ORE 3-month-olds prefer race of primary caregiver Newborns show no preference between races- “Other Species Effect” Anyone over 9 months of age cannot discriminate between two different monkey faces 6-month-olds can discriminate between the two- Perceptual narrowing Phenomenon of being able to perceive in particular ways in early childhood, but those abilities are lost due to experience4) Pattern Perceptiona) Infants experience integrative vision(i) Can infer patterns based on provided stimulib) Infants experience phi phenomenon the same way as adults5) Object Perceptiona) Perceptual constancy(i) Perception of a constant shape and size of an object(ii) Visual experience is not necessary to develop constancyb) Object segregation(i) Perception of separate objects in a visual field(ii) Detecting the visual boundaries of objects(iii) Effect of movement- Independent motion conveys separation of objects, even to an infant- No motion conveys no information to determine whether or not objects areseparated- Common motion conveys conjunction of objects- Still true even if two visible portions of object (or two exposed objects) appear different6) Depth Perceptiona) Optical expansion(i) Phenomenon of an object’s apparent increase in size as it approaches the viewer(ii) Present in infants as young as 1 monthb) Binocular disparity(i) Aka retinal disparity(ii) Difference between two visual inputs being sent to the brain from each eye(iii) Stereopsis- Visual cortex computes the degree of disparity and forms perception of depth- Begins developing around 4 months of age Newborns’ eyes only move in the same direction half of the time- Experience required to developc) Monocular cues(i) Depth cues requiring only one eye(ii) Aka pictorial cues(iii) Relative size(iv)Relative motion(v) Interposition(vi)Convergenced) Testing(i) Visual cliff- Tests presence of depth perception- 6 – 14-month-olds won’t cross Plexiglas side - 1.5 month-olds detect the depth change, but are unafraid- Experience-dependent Corresponds to amount of experience walking/crawling Infants who have experience with Plexiglas objects are less wary of cliff7) Ramifications of Visual Challengesa) Strabismus (lazy eye)(i) Sensitive period for binocular vision(ii) Dominant eye is patched to allow weaker eye a chance to catch upb) Congenital cataracts (reversible)(i) Project Prakash(ii) Sensitive period for object perception(iii) No sensitive period for cross-modal perception- Learning period required to experience cross-modal perceptionC. Auditory Perception1) Auditory localizationa) Estimated location of source of a sound2) Music Perceptiona) Infants’ response to music is similar to that of adultsb) Infants can perceive the difference between consonance and dissonance in music(i) Infants have perfect pitchc) Can remember pieces of music over an elongated period (a few weeks)d) Have innate perception of rhythme) Infants are able to recognize melodies beginning at 5 months of ageD. Taste and Smell1) Newborns have preference for sweet tastes over other tastes2) Newborns can also distinguish between the smell of their own mother and the smell of another womanE. Touch1) Infants begin to experience touch through their mouth2) Starting around 4 months, infants begin to transfer exploration duties to their hands instead of their mouths3) Sticky Mittens experiment conclusions (3-month-olds)a) Increased interest in objectsb) Earlier reaching to objectsc) Increased interest in facesF. Intermodal Perception1) Aka Cross-Modal perception2) Combining of information from multiple sensory systems3) Piageta) Claimed infants do not start to form associations between senses until a few months of age4) McGurk Effecta) Visual input alters speech perceptionb) Infants show McGurk effect by 5 months of age5) Modern theorya) Newborns’ instinct to look towards a sound indicates association of visual and aural sensory informationb) Infants create visual picture of an object by using their mouth, and can recognize an object after sucking on it, even if it was not physically seen(i) Meltzoff: pacifier study- 2 pacifiers: 1 smooth, 1 knobby Control group – breast-fed infants- Newborns preferred picture of familiar pacifier, even though they hadn’t seen it before experiencing it orallyc) Infants readily associate visual and aural stimuli, as in watching a video(i) Spelke: visual/auditory matching study- Two screens playing two different films of bouncing animals at different speeds- Soundtrack matching only one film- Infants (4-month-olds) preferred matching film(ii) 4-month-olds are able to perceive when a voice soundtrack is aligned with a video of a person speaking and when it is not(iii) Infants can perceive emotion through