Sensation and Perception Part 4 Flashcards
Perception is _____ and involves both _____-______ and ________-______ processing.
Constructive, bottom up, top down.
What is crucial in interpreting sensory experience?
The observer’s knowledge and experience
Who in 1890 described the perceptual world of the new born infant?
William James
What did William James describe the perceptual world of a newborn infant as?
A “blooming buzzing confusion”.
Why did William James describe the perceptual world of a newborn infant as a “blooming buzzing confusion”?
Because they lack the perceptual experience that adults have in order to interpret visual experience.
At birth, _____ capabilities are not fully developed.
Sensory
What is relatively poor at birth?
Vision is relatively poor.
What happens to the underdeveloped visual system at birth?
The visual system continues to mature after birth up until toddler years.
What cones are under-developed/poorly developed in newborns?
Foveal Cones
What does the inner segment of a foveal cone do?
It captures light energy.
In newborns, describe the structure of the inner segment of the foveal cone.
It is short and stumpy.
Because infants have a short and stumpy inner segment of their foveal cones, what does this mean?
It means that they can’t capture light energy as efficiently as adults can.
What is the other difference to do with foveal cones between newborns and adults?
In newborns the foveal cones are more widely spaced.
What does having more widely spaced foveal cones mean for infants?
It means that they wont be capturing the same amount of information as adults can therefore newborns will experience less detail than adults.
The _____ nerve _____ is incomplete at birth.
Optic, myelination.
Explain myelination.
The production of a myelin sheath to wrap around a nerve, which helps to conduct neural impulses.
What does the incompletion of myelination of the optic nerve in newborns result in?
It means that neural impulses can’t be transmitted as efficiently, therefore the travelling of information takes longer.
What else (apart from cones and myelination) isn’t fully developed at birth?
The visual cortex.
What layers of the visual cortex mature the earliest?
Deep cortical layers mature earlier than the superficial (outside) layers.
Because the visual cortex is underdeveloped in newborns, what does this result in?
It means that the interpretation of information isn’t as effective or efficient as adults.
It can be said that we can measure visual _______.
Acuity.
What chart do we use to asses vision?
Snellen Chart
The lower down the Snellen chart you can read, the ______ your vision.
Better
What does 20/200 vision mean?
The letter should be able to be seen from 200 feet away, but can only be seen from 20 feet away.
0-1 month olds have 20/_____ or 20/______ vision.
400, 600
What vision do infants between 6 and 12 months old have?
Approximately 20/40 or 20/30 vision.
Adults have near to ___/___ vision.
20/20
Name 4 ways we can measure perception in infants.
Preferential Looking
Sucking Rate
Visual Evoked Potential (VEP)
Tracking of a moving stimulus
Why is it difficult to measure perception in infants?
Because they are non-verbal and can’t responds as well as an adult.
What does sucking rate exploit?
Sucking rate exploits a baby’s natural behaviour to suck things.
Describe the sucking rate stimulus.
- Give baby a dummy which is hooked up to a machine
- Record sucking rate and look for changes of sucking rate on presentation of a stimulus
If a change in sucking rate occurs upon the presentation of a stimulus, what can we presume?
We can presume that the baby can perceive the stimulus.
If babies are able to track the movement of a stimulus with their eyes, what can we presume?
We can presume that the baby is able to perceive that stimulus.
What does VEP stand for?
Visual Evoked Potential
In VEP what is recorded?
The electrical activity of the brain.
In Visual Evoked Potential (VEP), how is the electrical activity of the brain recorded?
By putting electrodes on the scalp.
In VEP specific activity within the ____ indicates whether or not the image is _______.
Brain, perceived.
Describe what happens in a preferential looking experiment.
- 2 stimuli are presented simultaneously
- 1 stimuli is of more interest than the other eg. one patterned square and one blank square
- We then see if the infant will attend to that stimulus more than the other aka. have they perceived the pattern?
- The experimenter looks through a peephole and records what side the infant looked at.
In a preferential looking experiment, what makes it more reliable?
If the experimenter doesn’t know what side the stimulus of interest is on eg. is blind to it :)
In preferential looking, in what case can we presume that the infant perceived the pattern?
If they looked at the patterned square as apposed to the blank square.
If an infant reaches for a target, we assume they can perceive it. What is this known as?
Preferential Reaching
What did Walton, Bower and Bower 1992 find regarding babies and photos of women/mothers?
- Very young babies look longer at photos of their mother than photos of other women
- They also alter their sucking rate when they see a picture of their mother over another woman (even with same hair colour as mum etc.)
What did Quinn, Yahr, Khun, Slater and pascalis (2002) suggest?
They suggested that children had a preference for faces of the gender that was the same gender as their primary caregiver.
Children prefer the gender of the face that they have had more _____ with.
experience
Both of these facial experiments (Walton and Quinn) highlight the importance of what?
They highlight the importance of innate behaviour and experience.
Describe the experiment that Johnson, Dziurawiec, Ellis and Morton (1991) carried out.
- They showed infants face-like, non face like (scrambled) and blank paddles
- They measured how much infants followed these by moving their eyes and head
What was the result of the 1991 paddle face experiment?
Infants were found to show preference for face-like stimuli as early as 5 days old.
Turati, Valenza, Leo and Simon (2005) used _______ _______ to measure _____ ________ in the human ______.
eye tracking
perceptual interest
face.
3 month olds prefer ____ face images to _____ ones.
natural, unnatural
What do 3 month olds demonstrate that is not present in newborns?
Cognitive Specialisation.
In terms of faces and newborns what did Turati et al. (2005) find?
That new-borns are sensitive to configuration of features but not to faces specifically.
What does configuration of features mean?
How the features are arranged.
Newborn infants display a preference for certain _____ of face stimuli.
configuration
What does the new-born’s preference for face like configurations reflect?
They don’t yet have a general preference for faces but this preference may lead to its specialisation with increased experience.
What location is the face like pattern preferred to be in? (upper or lower half?) And why?
The Upper Half
The pattern is consistent to face like configuration of elements (eg. eyes and nose).
Name the 3 main classes of depth cue.
Kinetic (movement) cues Binocular Cues (stereopsis) Monocular (pictorial) cues- static cues.
Sensitivity to the 3 different depth cues appear to ____ at _____ _______.
develop
different rates
Optical Expansion/Looming is a ____ _____ cue.
Kinetic depth
What is Optical Looming?
The rapid increasing in the size of retinal image.
What sensation does Optical Expansion/Looming give us?
Optical Looming gives us the sensation that an object is coming towards us.
How can we tell if infants are sensitive to Optical Looming?
If they perceive the optical loom then they will blink defensively.
Infants as young as 2 months respond to optical ______.
Looming.
Acretion/Deletion of texture is a ______ ______ cue.
Kinetic depth
Another kinetic depth cue is _____ surfaces in ______.
texture, motion.
What does the accretion/deletion of texture surface infer?
That 1 part is moving in front and 1 part of texture has moved behind.
In what situation can we assume that infants perceived accretion/deletion of texture?
If they were able to reach for the nearer surface (using preferential reaching)
_____ parallax is an example of a _____ depth cue.
Motion, kinetic
What is evidence for the early development of motion parallax?
The Visual Cliff (Gibson and Walk, 1960)
Visual cliff- The whole table is glass however a checked pattern under the table creates the illusion that there is a _____.
drop
In the Visual Cliff experiment, what happened when the parent beckoned the baby?
The baby crawled until the perceived drop, but they wouldn’t cross past the cliff.
When the baby wouldn’t cross the “cliff” what does this prove?
It proves that the baby perceived the drop.
What is the flaw of the Visual Cliff experiment?
By the time human infants can crawl they will already have had approximately 8 months of visual experience.
The visual cliff experiment was tested on chicks that had just hatched and they did the same as the 8 month old babies, what does this show?
It shows that it must be learnt very soon after birth.
Each of our eyes has a slightly different _____- a combination of the 2 images gives rise to ______ _______.
view, stereoptic depth
Richard Held measured infants’ sensitivity to _____ cues using visual objects (as in 3D movies).
binocular
How did Richard Held measure infants’ sensitivity to binocular cues?
-He measure infants’ preferential looking to 1 stimulus that had depth and 1 that had no depth.
What did Held find? What can we conclude from this?
Infants of approx. 3.5 months preferred the cue that had depth in it.
From this we can conclude that infants don’t use disparity until approx. 3.5 months.
What is Stereoacuity?
It is a measure of stereopsis aka. how good/bad it is.
What is an arc second?
An angular measurement, the smaller the angle, the better the stereoacuity is achieved.
What did Brown, Lindsey, Satgunam and Miracle (2007) fiind about stereoacuity at 3 months?
They found that Stereoacuity is unmeasurable.
What did Brown, Lindsey, Satgunam and Miracle (2007) fiind about stereoacuity at 5 months?
At 5 Months, stereoacuity is 474 arc seconds.
What is the stereoacuity for an adult? (Brown et al.)
5-10 arc seconds
What can we conclude from the Brown, Lindsey, Satgunam and Miracle (2007) experiment?
That stereopsis emerges between 3 to 5 months, but it takes experience to have the arc second of an adult.
What cues are effective for a stationary observer in a motionless scene?
Pictorial Depth cues (monocular static depth cues)
Using monocular cues, what can we use and to infer what?
We can use the size of retinal image to infer how far or close an image is.
If a retinal image is smaller than the standard size, what do we perceive this as?
We perceive this as further away.
Name the monocular depth cues.
Relative Size Relative Height Linear Perspective Ariel Perspective Interposition/occlusion
What monocular cue did Yonas, Granrud and Pettersen (1985) test?
Relative Size
How did Yonas, Granrud and Pettersen (1985) test relative size?
- They tested 5 month, 5.5 month and 7 month old infants
- Used a pair of stimuli, 1 bigger and 1 smaller
- They used preferential reaching
- If infant had sensitivity to relative size then they would reach for the object that appeared closer (the bigger one)
At what age did infants display sensitivity to relative size?
At 5.5 months and at 7 months, but not at 5 months.
What is occlusion?
When an object in front of an other appears closer than the one behind it.
Granrud and Yonas (1984) used a reaching _____ and a stimuli that was interposed and another that was not.
paradigm
If infants are sensitive to interposition what should they do?
The should reach for the interposed shape.
It was found that ___ month olds but not _ month olds reached for the interposed stimuli in the experiment (Granrud and Yonas).
7, 5
What do the series of experiments from Grandrud and Yonas display?
That 7 month olds have sensitivity to monocular depth cues for certain.
Name the order of emergence of sensitivity to the depth cues:
- Around 2 months
- Around 5 months
- Around 7 months
- Kinetic Depth Cues
- Binocular Depth Cues
- Monocular depth cues
Why is the perceptual world of the newborn NOT a “blooming buzzing confusion”?
Because infants orient meaningfully to stimuli from birth, but extensive perceptual learning is clearly taking place.
Perceptual development is clearly very _______. Yet the infant’s perceptual ______ seems quite limited especially for ______-______ processing.
rapid, experience, top down (because have to have knowledge for this processing)
The question is, is perceptual organisation _____ or do we have the extraordinary ability to ______ how to ______ input, or it could be a bit of both!
innate, learn, organise.
