Vision: Development of Scene Perception

Question 1

How do we study visual development?

Answer 1

Looking behavior = e.g Preferential looking

Neuro measures = EEG, VEP, fNIRS

Observation / deprivation = Behaviour, Naturally occurring – cataracts, ‘Selective rearing’ (not humans)

Things that aren’t children= Neural networks, Robots / AI, Adult

Question 2

Example of studying at baby’s looking bhvr

Answer 2

Preferential looking = Fantz 1956, Fantz & Nevis, 1967 saw the applications

Other ways to use looking behaviour for babies
Habituation
Novelty preference
Eyetracking
VoE

reliable + reveal biases in the infant visual system e.g bias to high contrastimages and ‘face like’ stimuli

Question 3

Adult vision

Answer 3

Visual Acuity
Colour
Depth
Size
Shape
Orientation
Segmentation
Transparency
Opaqueness
Motion
Constancy
Etc..

Question 4

What is visual acuity?

Answer 4

Poor at birth, but by 36 months old children have 20/20 vision
Although acuity is poor, the general pattern for CSF is very similar to adults

Kiorpes (2016) = development of contrast sensitivity

The world is very blurry when kids are very young

Question 5

Is there an advantage to low initial acuity?

Answer 5

immaturity of the infant visual system = provide the best learning ground for discriminating faces.

Teaches weighting of configuration of faces over local processing

Question 6

What is the Neural Net (vogelsgang et al, 2018)?

Answer 6

The image gets clearer after seeing multiple faces. Integrate where the everything.

Question 7

Evidence for impaired face perception - cataracts

Answer 7

People w/ cataracts
Have the same amount of cell maturation but a different amount of experience you get when you are trying to see

People can see the are different people straight away = takes longer for people w/ cataracts. Real world evidence/
LeGrand et al 2001,
Geldart et al 2002.

Question 8

What does low initial acuity suggest?

Answer 8

critical periods = period in development when perceptual
systems are sensitive to environmental stimuli

Question 9

Explain colour vision in babies

Answer 9

although all the cones are present = infant retina + pathways to colour = immature at birth.

But, infants can see some colour from birth + by 3-4 months old = trichromatic.

Question 10

Adams (1989)

Answer 10

newborns = look longer at the red-like than the achromatic light (grey). Look at blue + achromatic light equally. They have a reddish colour vision but not yet blue dimension

Question 11

How does colour discrimination in colour vision develop in babies?

Answer 11

Colour discrimination is half with every doubling of age + ratio of input of the cones is the same across the
lifespan

8m = is 2x of 4 months

Question 12

How does depth and size perception develop in babies?

Answer 12

Very young children can perceive depth, as illustrated by heart rate measurements

Visual clef experiment = support this

Size constancy = some form in newborn infants, but the integration between perception + action = unperfected.

Young children some skills for size constancy, but don’t necessarily integrate across visual cues (failing to integrate cue for depth perception, Nardini et al. 2010)

Question 13

Name studies supporting size constancy in newborns

Answer 13

Slater et al (1990)
Granrud, et al (1987)

Question 14

What is perceptual learning?

Answer 14

Learning to make sense of the perceptual input that we receive

Question 15

What is a scale error?

Answer 15

A failure to integrate visual info and with the information they have already learnt

Question 16

how does early visual experiences affect the way a person may behave as an adult?

Answer 16

Although biases in infant looking behavior from birth = refinement of perception based on visual experience in the first year of life

very important = significant influence on perception

Question 17

What is perceptual narrowing?

Answer 17

Experience/ lack of experience shapes perceptual experience = ‘use it or lose it’ refinement

A critical period for stimulation.

Question 18

What happened in Pascalis, de Haan & Nelson , 2002

Answer 18

6 vs 9 month old
see also similar effects for baby faces
Babies 6m = can identify the differences better than 9mths
Lost that ability at 9m

Question 19

What is the other ethnicity effect

Answer 19

better at discrimination your race than other races

Question 20

What are the effects of natural scenes?

Answer 20

Holes = trypophobia

Trypopobic images = excess of energy at the mid spatial frequencies = matches the spectral profile of some
hazardous animals, such as snakes.

Aesthetics are influenced by low level properties of an image.

Question 21

what is natural scene statistics?

Answer 21

How environment vary in predictable and measurable ways e.g golden ratio

We expect that our perception is shaped by fixed adaptations and
plastic adaptations.

Any scene that you can come across

Question 22

What is image analysis?

Answer 22

Images = broken down into low level + high level properties. We can find what’s common across all natural scenes + how / if the visual system lines up with it.

Colour information = e.g. Colour intensity (saturation). Range of colour

Spatial information = e.g Fractal dimension. Spatial frequency (low detail and fine detail

Question 23

What is the applications of image analysis?

Answer 23

Companies like Netflix = use more/ less saturation on thumbnails to get people to watch them

Question 24

What is spatial stats in the natural science

Answer 24

Natural scenes have a 1/f distribution of spatial frequencies, and neurons in the primary visual cortex have response profiles
optimised to process this information.

What contrast information is present?
Low spatial frequency (fine detail) + high spatial frequency (low detail) in this image

Way to describe the spatial freq. contrast vary in an image

Question 25

Which slope are adults sensitive to?

Answer 25

The are sensitive to scenes that vary around 1/f slope and insensitive to scenes that aren’t

Children not sensitive until 10 bc immaturities in low level vision

Question 26

Describe natural stats and colour

Answer 26

The spectral sensitivities of human colour receptors have evolved to optimally represent the variation in colour of blood flow
and diets of our ancestors

Natural scenes contain the greatest amount of variance along one particular direction in colour space (cerulean line : blue
yellow’. This is also the way that sunlight and skylight vary.

Natural scene statistics in infancy can impact on adult colour perception into adulthood

Question 27

How is aesthetics and natural scenes linked ?

Answer 27

More ‘natural’ distributions of colour are higher in artistic merit, and less natural distributions are more uncomfortable to look
at