Lecture 1 - Perception Flashcards
Sensation Definition
Information about environment picked up by sensory receptors and transmitted to brain
Perception Definition
Interpretation by the brain of this input (how we understand the events, objects and people in our environment)
Visual Acuity Definition
Ability to process fine detail
When does visual acuity develop?
Poor at birth, rapid increase in first 6 months.
Near adult levels by 1 year
Visual Scanning Definition
The ability to track objects
When does visual scanning develop?
Younger than 2 months, cannot track moving objects smoothly
1 month – focus on limited features of shape, particularly outside edges
2 months: start to focus on internal features
When does colour vision develop?
Newborns can distinguish between white and red, but not other colours (ex: Adams et al. 1994)
Around 1 month, look longer at brighter, bold colours
By 4 months close to adult ability
What is a preference test?
Present two stimuli at the same time and measure how long an infant looks at each.
Franz (1961)
Infants spend more time looking at a face, but enjoy more complex shapes too.
1-15 week old babies prefer a more complex pattern, face or not.
What are habituation tasks?
Shown interesting stimulus repeatedly so child loses interest, change to a different stimulus so infant has renewed interest and looks again (dishabituation) – this sees if infant can tell the difference between stimuli
What are conditioning tasks?
Repeatedly reward target behaviour (like increased sucking rate). Infant becomes habituated to stimulus. Stimulus is altered – if infant does not increase sucking rate treats 2 stimuli as the same, if not can tell the difference.
Face perception quote (Moulson et al, 2009)
“Faces are arguably the most important visual stimulus used in human social communication”
Why is face perception useful?
What can you tell from a face? (species, sex, race, identity, mood, intent)
Crucial ability for successful social life.
Maurer and Barrera (1981)
At 1 month there was no difference in looking times and at 2 months they preferred to look at a neutral face.
Goren et al (1975)
Used moving stimuli instead of static and found newborns track schematic face more than complex patterns/blank shape.
Johnson et al (1991)
Replicated Goren et al study and found that after 3 months they no longer track more
2 Process Model researchers
Johnson and Morton (1991)
2 Process Model parts
CONSPEC – early system (subcortical structures) biases infants towards faces, CONLEARN – later taken over by more mature system (visual cortex) and more precise recognition
Slater et al (2000)
Newborns under a week old looked longer at attractive faces.
Bushnell, 2001; Pascalis et al, 1995
Babies can discriminate mother’s face to others
Walton et al (1992)
Infants sucked more to keep mother’s face on video at 1-4 days old
Pascalis et al (1995)
Preference for mother’s face disappeared when outside of face and hairline masked, newborns use outer features to identify
Turati et al (2006)
Babies could use both outer and inner features to identify a face
Sugita et al (2008)
Monkeys not exposed to faces for first months of life still preferred them
Pascalis et al (2002)
6 month olds could discriminate between monkey faces and human faces, 9 month old infants and adults could only discriminate between human faces
Pascalis et al (2005)
If exposed to monkey faces, 9 month olds could discriminate
“Other race” effect (Tanaka et al, 2004)
Adults are poorer at discriminating faces of other races compared to own race
Kelly et al (2005)
At 3 months old infants prefer faces of their own race
Sangrigoli et al (2005)
Korean adults adopted between 3-9 years old into Caucasian families became more accurate differentiating between Caucasian faces
Quinn et al (2008)
Preference for female faces at 3 months old
Quinn et al (2002)
When fathers are primary caregivers the children have a preference for their faces
Wismer, Fries and Pollack (2004)
Instituationalised children showed deficits in identifying emotions in faces
Pollack et al (2000)
Children raised in abusive environment show bias for angry faces
Adult Face Perception
Adults can recognise familiar faces within half a second and retain information of large number of faces (90% recognition of yearbook photos in a class size of up to 900 up to 35 years later) Some research suggests this expertise doesn’t emerge until after 30+ years of learning
Face Specific Perceptual Development Theory
Ongoing development of face-specific perception mechanisms; continue to develop into late childhood and adolescence
Face perception gets better because of increased exposure / experience with faces
General Cognitive Development Theory
Face perception matures early (4-5 years?)
Performance increases later as general cognitive mechanisms improve.
Disproportionate Inversion Effect
More accurate when faces are upright, larger effect for face versus non-face objects
Holistic/Configural Processing
Integration of information from all regions of face, code spacing between face and features
Crookes and McKone (2009)
As young as 4-5 years old adult-like face perception is developed
Susilo et al (2013)
Tested over 2000 18-33 year olds and controlled for non-face visual recognition, sex and own race bias. Positive association between age and facial recognition abilities and conclude results support “late maturation hypothesis”
Young and Burton (2018)
Differences between familiar and unfamiliar faces in adult face perception
Jenkins et al (2011)
Quizzed UK university students to see how many of a list of Dutch celebrity photos are the same person and they overestimated. Dutch students did not
ASD and social cognition
Trouble recognising familiar people, remembering faces and interpreting eye-gaze and emotions
William’s Syndrome
Unfamiliar faces are seen as more approachable and they have a prolonged face gaze (Riby et al, 2008)
Prosopagnosia (face blindness)
Damage or abnormalities in right fusiform gyrus (due to stroke or brain injury)
Congenital prosopagnosia starts from birth and runs in families
There are different degrees of severity
