Transcript lecture 11

PSYCH 2220
Perception
Lecture 11
Do we need to LEARN to see?
KEYWORDS for lecture 9
"do we need to learn to see?",
empiricists (yes), nativists (no),
innate visual behaviours, dung beetle, chimpanzees
and snakes, ducklings and hawks, Molyneux's question
("if a man is given his sight as an adult, could he
distinguish a sphere and a cube?"), two patients
described, babies, mixed up faces, visual cliff,
contrast sensitive function for infants, preferential
looking, adaptation (remember that Dalmatian!),
inverting prisms, hens show no adaptation, horizontal
or vertical rearing
EMPIRICIST
(all knowledge comes from experience)
NATIVIST
(knowledge is ‘a priori’; you are born with it)
1 animal behaviour
Molyneux’s question:
“could a man born blind distinguish a
sphere and a cube by sight alone?”
2 blind people recovering sight
S.B could see with minimal experience
H.D. never could see very well.
3 child development, Fant’z Experiment
4 adaptation
walks actively
carried passively
5 controlled rearing
EVIDENCE
Animal behavour
……………………. Nativist
Blind people recovering their sight… Empiricist & nativist
Babies’ visual development …………. Empiricist & nativist
Adaptation experiments
…………… Empiricist
Controlled rearing experiments
……….. Empiricist
INTRODUCTION TO HEARING
malleus
incus
stapes
}
little bones
(ossicles)
leverage= 1.3 x
helicotrema
}
pinna
tympanic membrane oval window
(external ear) (ear drum)
OUTER EAR
MIDDLE
EAR
area
decrease
17 x
INNER EAR
this section coiled up
in the actual ear (cochlea)
top tube
middle tube
bottom tube
tectorial membrane
basilar membrane
hair cells
vibrations pass down the top tube to the
end (the HELICOTREMA) and then
back down the bottom tube.
oval window
vibrates most to
high frequencies
(around 10 kHz)
helicotrema
vibrates most to
middle
frequencies
(around 1 kHz)
vibrates most to
low frequencies
(down to around
27 Hz)
hairs
hair cell
nucleus
fibre of 8th nerve (auditory nerve)
ACTION POTENTIALS
TO BRAIN
Auditory system 13 - 5
this line shows the
quietest sounds you
can hear. At sound
pressure levels below
this line you can't hear
the sound.
(loudest)
100
80
sound level 60
in decibels
40
(dB)
20
0
(quietest)
(low)
can hear
can't hear
10
100
1000
10,000
Frequency (Hz)
(high)
EQUAL LOUDNESS CURVES
(loudest)
100
80
sound level
in decibels 60
40
(dB)
20
0
(quietest)
(low)
*
*
All points on
this curve
All points on
have the
this
curve
All
same points on
have
the
this
curve
perceived
same
have the
loudness
as
perceived
thesame
standard
loudness
as
perceived
(*)
the
standard
loudness
as
(*)the standard
(*)
*
10
100
1000
10,000
Frequency (Hz)
(high)
Place theory
1 - Travelling wave; stiffness varies
2 - one place most active for a given frequency
3 - tonotopic code; coded as place
Periodicity theory
1 - sound coded as pattern
Hearing thresholds
Equal loudness
Masking
The case of the missing fundamental
harmonics
pitch
timbre
Training
a goldfish...
Evidence against place
-- Missing fundamental
-- which can be masked
-- some animals have no
basilar membrane
Evidence for place
-- physiology
Evidence against periodicity
-- cells can’t fire fast enough
-- diplacusis
Evidence for periodicity
-- multiple cells could do it
-- phase locking of cells
Place theory
sound coded as place
Periodicity theory
sound coded as pattern
Duplicity
below 1kHz, coded by periodicity
above 1 kHz, coded by place
Auditory localization
1 inter-aural time of arrival differences
-- circle of confusion
2 inter-aural intensity differences
3 pinnae (up/down front/back etc..)
4 head movements
hairs
hair cell
nucleus
fibre of 8th nerve (auditory nerve)
ACTION POTENTIALS
TO BRAIN
Auditory system 13 - 5
The Auditory
System
Auditory cortex
Auditory thalamus
Superior colliculus
Inferior colliculus
cochlea
Cochlear nucleus
Superior olive
The Auditory
System
(cortical route)
cortex
thalamus
Inferior colliculus
Cochlear nucleus
The Auditory
System
(sub-cortical route)
Superior colliculus
Inferior colliculus
Cochlear nucleus
Superior olive
The Auditory
System
The Superior
Colliculus
front
a
left
a
f
c
b
g
d
back
b
d
a
c
right
LOCALIZATION OF FUNCTION IN THE CORTEX
Phrenology
• Stimulation
• recording
• lesions
• anatomy
Motor cortex
Somatosensory cortex
Visual cortex.
FRONT
Olfactory cortex
Auditory cortex
PARIETAL CORTEX (the
"WHERE" system)...
FRONTAL
CORTEX (involved
in personality)
INFEROTEMPORAL CORTEX
(the "WHAT" system).
PARIETAL CORTEX (the
"WHERE" system)...
FRONTAL
CORTEX (involved
in personality)
INFEROTEMPORAL CORTEX
(the "WHAT" system).
Phineas Gage
BROCA'S AREA
(speech production)
WERNICKE'S AREA
(speech comprehension)
corpus
callosum
from above
from front
THE
CORPUS
CALLOSUM
LEFT
VISUAL
FIELD
RIGHT
VISUAL
FIELD
LEFT
BRAIN
RIGHT
BRAIN
left eye sees
right eye sees
right hand
touches
left hand
touches
“SPLIT BRAIN”