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43 Cards in this Set
- Front
- Back
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What is sensation? |
Information received by sensory organs Brain receives input from sensory organs |
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What is perception? |
Interpretation of the information received by sensory organs Brain makes sense out of the input |
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How is sensation and perception studied in infants? |
Methodology: see if infants can differentiate between 2 stimuli - Habituation/dishabituation - Preference technique - Operant conditioning |
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What is the Preference Technique? |
If a baby prefers to look at one stimulus over another, this indicates the baby knows the two stimuli are different Preference=know differences Babies looking at one thing more than another because it may be more interesting/a novel object |
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Fantz' Looking Chamber |
Baby lays underneath a looking chamber and objects presented to baby Look at baby's corneal reflection to determine which object the baby is looking at - Children find complex stimuli more attractive than simple objects - Babies prefer looking at their mother compared to other women |
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Modern Day Preference Techniques |
Eye tracking machinery: records where baby is looking (exactly, like what part of the face baby is looking at) |
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Preference Technique for Auditory Stimuli |
Baby sits on mother's lap When they look to the right they hear one sound and when they look to the left they hear a different sound If they look to one side more than the other, you know they can tell the difference between the two sounds |
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Habituation/Dishabituation technique |
Habituation: when a baby is shown the same thing repeatedly they get bored so their looking time decreases Ex. if you show a baby the same toy over and over again they will stop looking because they are used to it, no longer interested In experiment, shown one or two objects, wanting to know if they can tell difference between one object and two objects present Looking at one object more than other doesn't mean they like one more than the other, it means the old one is boring and the new one is interesting |
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When is a baby habituated? |
When the looking time decreases by at least half |
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Operant Conditioning Technique (aka conditioned head turn procedure) |
You train the baby to understand when he turns his head at the right time (when there is a change in stimulus), he gets a reward Training: baby sits on mother's lap and you present stream of stimuli and then when you change the stimulus (new stimulus), you also increase the volume so they will turn their head and be rewarded Experiment: after training, you present one stimuli then present new stimuli with no volume change (Mother and observer listening to masking sounds) Results: At 6 months of age, babies can tell the difference between monkeys and humans voices but once they reach 12 months they can only tell the difference between human voices |
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Development of Sensory Organs |
Sight, hearing, taste, olfaction, touch You get more taste, smell, touch and hearing than vision in the womb |
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Why might some senses adapt faster? |
Adaptive value! Taste usually developped first because we want to avoid eating poisonous things |
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Taste |
Developed in utero Highly developed At birth, responses and preferences to taste Newborns like sweet foods 6 months they also like salty foods |
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Taste: Study of Amniotic Fluid |
Amniotic fluid has a particular taste determined by what a mother eats Experiment: Long lasting preferenes for tastes followed by prenatal exposure Exp Group- drank carrot juice 4 days a week in last 3 months of pregnancy Control Group- drank water Result: Babies with moms that drank carrot juice responded better to carrot juice at 6 months than babies with moms that drank water Conclusion: what your mother eats when you are in the womb influences your taste preferences as a baby |
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Taste: Study of baby tasting |
Experiment: see if babies can differntiate between sweet, salty, sour and bitter Gave the tastes and took pictures of facial expressions
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Smell |
Functioning right from birth Preference for human milk smell At 4 days old, prefer smell mother's breast milk than stranger's breast milk Also prefer smell of mother's amniotic fluid compared to other women's |
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Touch |
Fairly well-developed in the womb Can grasp umbilical cord and suck thumb Upon birth, develops earliest around mouth, palms of hands and soles of feet |
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Touch: Reflexes |
Rooting Reflex: if you touch baby on cheek it will turn its mouth towards it (nipple for milk) Sucking Reflex: if you put object near baby's mouth it will suck it Grasping Reflex: if you put finger in their hand they will grasp it- may not be adaptive for humans but for other species Babinski Reflex: if you touch sole of baby's foot the baby's toes will fan outwards because the corticospinal tract is not fully myelinated (Abn in adults) |
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Vision |
Least developed at birth Newborns have general sense of light and darkness Newborns visual acuity: 20/200 to 20/400, something an adult can see at 200 feet a newborn can see at 20 feet Age of 2 visual acuity: 20/20 |
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Fantz' Research on Visual Acuity |
Displayed uniform grey blob then series of B&W stripes (thick to thin) If preferred stripes, can conclude baby can tell difference Continue to show thinner stripes until no longer have a preference Can conclude that they cannot tell difference between grey picture and stripes and can conclude about visual acuity |
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Colour Vision |
We have color detecting cones in eyes (yellow/blue and red/green) Newborns can see black/white and red/green Can not see blue/yellow until 3-4 months |
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Visual Tracking |
If object is moving in environment you can track it with your eyes 6 weeks: developed (quickly) 10 weeks: fully developed Most likely tracking mother's face, preference for it |
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Depth Perception- Why is it an important childhood skill? |
Want to know distance of objects Ex. how far mother is way or floor so you don't fall down stairs Baby can see nipple coming towards it and prepare for feeding |
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Cues that indicate depth |
Pictoral (Monocular Cues) Kinetic Cues |
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Pictoral Cues |
Only need one eye to detect depth Interposition: knowing something is being blocked because there are other things in front of it Linear perspective, relative size: the smaller object is further than the larger one Have to have some experience with the world to develop these cues so this does not develop until 6 months |
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Binocular Cues |
Using both eyes to detect depth Reliable at 4 months of age |
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Kinetic Cues |
If you are in motion the things close to you seem to move faster than the things further away Visual Expansion: When something gets closer to you then it becomes bigger |
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Testing Depth Perception: The Visual Cliff |
Mobile non-human babies: used a checkerboard that drops to the floor making it look like a cliff, they put the baby on the plank and the mother will stand either near the cliff side or the normal side, they tested between 6 and 12 months All the babies would come over to the safe side when the mother called but none of the babies would come over to the cliff side The more experience you have being mobile, the more likely you are to not go over the cliff Babies >6 months HR would increase indicating fear |
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Testing Depth Perception: The Visual Cliff Continued |
Goats: took goats from the womb and none of them would go to the cliffside Rats: mostly nocturnal and do not use their vision much so they would go over to the clfif side; they rely on tactile cues so if the plank was actually higher they would detect this and not go over |
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Testing Depth Perception: The Visual Cliff Non-Mobile Human Babies |
They tested babies 2 months and up When placed on cliff side and measured HR: increased meaning they are interested |
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Face Perception |
Preferences for faces over non-faces U-Shaped Curve: ability is there at first then it disappears and comes back again - Newborns show preference - One month old show no preference - 2 months old and over have higher preference Johnson et al. (1991) Would show face, scrambled faces, and blank faces |
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Do babies prefer some faces over others? |
Walton (1992): Newborns prefer mom's face Langlois (1990s): Babies prefer attractive faces |
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Perceptual Narrowing for Faces |
Perceptual Narrowing: Our perceptual systems move from general to specific with experience <6 mo: discriminate faces from native and non-native categories for race and species 6 mo: start to specialize 9 mo: native categories only for race and species- only can differentiate between people in own races |
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Is it a strict maturational timeline or is it based on experience? Sugita (2007) Infant Monkeys |
Reared infant monkeys from birth with no exposure to either human or monkey faces
Delayed exposure for 6, 12 or 24 months Before deprivation: they were tested to see if they could discriminate between humans and monkeys and they could After deprivation: exposed to either human or monkey for one month Monkeys exposed to monkeys: only able to differentiate between monkey faces Monkeys exposed to humans: only able to differentiate between human faces |
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Is it a strict maturational timeline or is it based on experience? Sugita (2007) Infant Monkeys Continued |
For a full year they were exposed to both humans and monkeys, and the one month exposure period still shaped their ability to differentiate (i.e. monkeys exposed to monkeys could only identify monkeys and same for humans) |
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Overall Conclusion of Sugita Infant Monkeys |
Window of plasticity is not strictly based on maturational timeline but plasticity reduces with maturation |
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Hearing |
Occurs in the womb 20 weeks: fetus develops ear Then neurodevelopment occurs for the ear 25 weeks: auditory system developed Baby can hear muffled sounds beyond womb (breathing, digestion, mother, other people) Quietest sounds the newborns can hear is four times quieter than sounds adult can hear |
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Hearing: After Birth |
Speech: babies prefer speech over non-speech and can discriminate it Voices: by the time they are 4.5 mo they can recognize names Music: young babies can distinguish between melodies in music; they prefer pleasant melodies (constant) over non-pleasant melodies (dissonant) Perceptual narrowing occurs with rhythmic patterns too |
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Hearing Study: Soother and Sucking Behaviour |
Sucking behaviour measured to determine if they recognize mother's voice During rest period of sucking (they suck for a period then rest for a period), they would put their mom's voice on and the babies sucking would rest for a longer period if they got rewarded Can discriminate moms voice and prefer's mom's voice |
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Sound Localization |
U shaped developmental curve - Thought it might be because child not behaving to signals sent to cortex - May be developing with visual system because we test them by seeing if they look but since visual field is not developed they may not look because of that not because of hearing |
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How do we measure sound localization? |
Sit on mother's lap and have speakers at 0 degrees and 90 degrees Look at localizing behaviours Midline is 0 degrees, right in front of face Birth-1 mo: orient to objects 60 degrees from midline 1-3 mo: disappears 3-4 mo: reappears, becomes faster/accurate |
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Motor Development: Locomotion How does the world change as the baby moves from sitting to crawling to gliding to walking? |
The role of experience Karen Adolph's Research: looks at how babies navigation resets when they go from crawling to walking No evidence that walking early or late has any impact on future |
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Motor Development: Fine Motor Skills |
Reach for objects by 4 months Grasp precisely by 7 months Handedness |
