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![Page 1: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/1.jpg)
![Page 2: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/2.jpg)
Masking occurs whenthe perception of a brief stimulus (the target)is impaired by another stimulus (the mask)
presented in close temporal and spatial contiguity
Masking occurs in two main flavours:a) by integration (camouflage)b) by interruption:
i) metacontrast masking ii) pattern maskingiii) object-substitution masking
Why study masking?Because it opens a window on the mind/brain
Let’s start with integration…
![Page 3: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/3.jpg)
Masking by temporal integration
CW:Masking by temporal integration is mediated
by visible persistence(iconic memory)
Visible Persistence: an image that remains visible for a brief period after the display has been turned off. (NOT a retinal afterimage)
![Page 4: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/4.jpg)
Sensory store
Storage model of visible persistence(hydrodynamic metaphor)
![Page 5: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/5.jpg)
sensory store visible persistence
Storage model of visible persistence(the metaphor can also be electrodynamic)
time
(10 ms)
![Page 6: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/6.jpg)
How can we measure the duration of visible persistence?
Task: name the matrix location of missing dot
Present the matrix in two sequential frames, separated by an ISI
ISI
F1 F2
![Page 7: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/7.jpg)
Short ISI
F1 F2
time
ISI
timeF1 F2
![Page 8: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/8.jpg)
Long ISI
time
ISIF2F1
timeF1 F2
No overlap
No integration
![Page 9: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/9.jpg)
VDLJHBJDR
ISI (ms)
100
80
60
40
20
040 80 120 160 200
Perc
ent
corr
ect
mat1 noarg space
time
ISIF1 F2
ISI F2F1
ISI F2F1
![Page 10: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/10.jpg)
VDLRGBSKP
100
80
60
40
20
010 80 120 160 20040
Duration of F1 (ms)
Perc
ent
corr
ect
F1 F2ISI
mat1 noarg space
F1 ISI F2
timeISIF1 F2
Charging the sensory store (increasing the duration of F1)
![Page 11: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/11.jpg)
F1 F2
F2 F1
F1 duration = 16 ms
F1 duration = 300 ms
(ISI = 0)
mat1 noarg space
![Page 12: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/12.jpg)
F2
F1
When F1 is long, integration breaks down.F1 and F2 become segregated
In fact, when F1 is long, F1 and F2 become segregatedeven when displayed concurrently
Demo: mat2 20-1-0
![Page 13: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/13.jpg)
Visible persistence is time-lockedto the onset of the stimulus, not to its offset
This also meansthat visible persistence
is not based on a decaying sensory store.
This means that temporal integration followsan SOA law, not an ISI law
![Page 14: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/14.jpg)
Visible persistence is linked to a burst of neural activitytime-locked to stimulus onset
(Duysens, Orban, & Maes, 1985).
![Page 15: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/15.jpg)
In brief,The duration of visible persistence varies inversely
with stimulus duration(inverse-duration effect)
F2time
F1
F1 F2
F1 F2
![Page 16: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/16.jpg)
The onset of a stimulus creates an image of itself(opens an object file)
that accepts new data for a very brief period(the critical period of integration)
All these effects(integration at short SOAs and segregation at long SOAs)
can be explainedbased on ideas of von Holst (1954) and MacKay (1957)
After that, the image acts as a filter that passesonly new stimuli
![Page 17: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/17.jpg)
The critical period is up:the object is complete.No more parts can beadded.
Short SOA:
F1 F2
![Page 18: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/18.jpg)
The critical period is up:the object is complete.No more parts can beadded.
Long SOA with ISI:
F1 F2
ISI
![Page 19: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/19.jpg)
F1
F2Long SOA, no ISI:
![Page 20: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/20.jpg)
Applying the principles of temporal integrationto forward masking by pattern
mask target
![Page 21: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/21.jpg)
mask target
Demo: int1-4
Masking by temporal integration
msk
time
tgt
![Page 22: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/22.jpg)
mask mask + target
Demo
mask
time
tgt
In the matrix task a long F1 produced segregation.A long leading mask produces unmasking.
![Page 23: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/23.jpg)
seg1-4
mask
time
tgt
![Page 24: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/24.jpg)
DURATION OF LEADING MASK (ms)
tgtmsk
![Page 25: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/25.jpg)
DURATION OF LEADING MASK (ms)
tgt
msk
![Page 26: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/26.jpg)
(Long SOA)
maskmsk+tgt
An account based on ideas of von Holst (1954) and MacKay (1957)
mask
tgt
![Page 27: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/27.jpg)
On the basis of this evidence, one might conclude that forward masking neveroccurs when the leading mask is displayed for longer than about 100 ms
But note the effect of task switching (e.g. conventional display sequence in masked priming)
![Page 28: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/28.jpg)
5 5
React
ion
Tim
e (
ms)
300
320
340
360
380
400
420
440
StreamNoStream
C7
59
23
7
C
StreamNo
stream
No forward masking in either case when no backward mask is presented
RT differences mediate more backward masking in the Stream condition
Not d
ue to
onse
t tra
nsient
Leading DistractorsGrid Noise Digit Script
React
ion T
ime (
ms)
300
320
340
360
380
400
420
440
![Page 29: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/29.jpg)
![Page 30: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/30.jpg)
Masking occurs in two main flavours:a) integration (camouflage)b) interruption: i) metacontrast masking ii) pattern masking iii) object-substitution masking
![Page 31: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/31.jpg)
Metacontrast masking
No spatial overlap between target and mask
When target-mask SOA is short, the target’s visibility is reduced(but not when SOA is equal to zero)
![Page 32: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/32.jpg)
TARGET
Conventional demonstration of metacontrast masking(visibility ratings)
![Page 33: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/33.jpg)
MASK
Conventional demonstration of metacontrast masking(visibility ratings)
![Page 34: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/34.jpg)
SOA = 0
No masking
(10 ms)
(10 ms)
![Page 35: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/35.jpg)
![Page 36: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/36.jpg)
![Page 37: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/37.jpg)
Stimulus sequencein metacontrast masking
SOA
![Page 38: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/38.jpg)
![Page 39: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/39.jpg)
![Page 40: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/40.jpg)
Target Mask Target + Mask
Visibility ratings are subjective
![Page 41: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/41.jpg)
SOA = 0
No masking
(10 ms)
Target
(10 ms)
Mask
![Page 42: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/42.jpg)
sim
![Page 43: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/43.jpg)
sim
![Page 44: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/44.jpg)
sim
![Page 45: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/45.jpg)
sim
![Page 46: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/46.jpg)
Target
Mask
Stimulus sequencein metacontrast masking
SOA
ISI
![Page 47: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/47.jpg)
seq
![Page 48: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/48.jpg)
seq
![Page 49: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/49.jpg)
seq
![Page 50: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/50.jpg)
seq
![Page 51: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/51.jpg)
U-shaped curve
![Page 52: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/52.jpg)
Figure 2
SMG
SOA (ms)
40 80 120 1600
20
40
60
80
100
MIR
40 80 120 1600
VDL 20
40
60
80
100
AVM
ISI:Tgt Dur:
Tgt Lum:Msk Dur:
Msk Lum:
ConditionBr. Mtch. Gap
0 variedvaried 10varied 100
10 10100 100
Per
cent
age
of c
orre
ct r
espo
nse
s
20
40
60
80
100
Gap
AverageBr. Mtch.
Figure 2
SMG SMG SMG
SOA (ms)
40 80 120 1600 40 80 120 1600
20
40
60
80
100
20
40
60
80
100
MIR MIR
40 80 120 1600 40 80 120 1600
VDL 20
40
60
80
100
20
40
60
80
100
AVM AVM
ISI:Tgt Dur:
Tgt Lum:Msk Dur:
Msk Lum:
ConditionBr. Mtch. Gap
0 variedvaried 10varied 100
10 10100 100
Per
cent
age
of c
orre
ct r
espo
nse
s
20
40
60
80
100
20
40
60
80
100
Gap
AverageBr. Mtch.Gap Gap
AverageBr. Mtch.Br. Mtch.
% c
orr
ect
resp
onse
s 100
80
60
20
40
0 40 80 120 160
SOA (ms)
No ISI
With ISI
tgt msk
SOA
![Page 53: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/53.jpg)
Effect of varying the SOA
![Page 54: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/54.jpg)
SOA = 0
![Page 55: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/55.jpg)
SOA = 100
![Page 56: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/56.jpg)
SOA = 200
![Page 57: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/57.jpg)
SOA = 300
![Page 58: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/58.jpg)
SOA = 500
![Page 59: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/59.jpg)
Effect of target-mask separation
(SOA = 100 ms)
![Page 60: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/60.jpg)
Sep = 1
![Page 61: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/61.jpg)
Sep = 2
![Page 62: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/62.jpg)
Sep = 3
![Page 63: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/63.jpg)
Sep = 4
![Page 64: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/64.jpg)
Sep = 5
![Page 65: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/65.jpg)
Reducing the mask’s contours(SOA = 100 ms)
![Page 66: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/66.jpg)
4 dot 1
![Page 67: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/67.jpg)
4 dot 2
![Page 68: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/68.jpg)
4 dot 3
![Page 69: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/69.jpg)
4 dot 4
![Page 70: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/70.jpg)
Figure 2
SMG
SOA (ms)
40 80 120 1600
20
40
60
80
100
MIR
40 80 120 1600
VDL 20
40
60
80
100
AVM
ISI:Tgt Dur:
Tgt Lum:Msk Dur:
Msk Lum:
ConditionBr. Mtch. Gap
0 variedvaried 10varied 100
10 10100 100
Per
cent
age
of c
orre
ct r
espo
nse
s
20
40
60
80
100
Gap
AverageBr. Mtch.
Figure 2
SMG SMG SMG
SOA (ms)
40 80 120 1600 40 80 120 1600
20
40
60
80
100
20
40
60
80
100
MIR MIR
40 80 120 1600 40 80 120 1600
VDL 20
40
60
80
100
20
40
60
80
100
AVM AVM
ISI:Tgt Dur:
Tgt Lum:Msk Dur:
Msk Lum:
ConditionBr. Mtch. Gap
0 variedvaried 10varied 100
10 10100 100
Per
cent
age
of c
orre
ct r
espo
nse
s
20
40
60
80
100
20
40
60
80
100
Gap
AverageBr. Mtch.Gap Gap
AverageBr. Mtch.Br. Mtch.
% c
orr
ect
resp
onse
s 100
80
60
20
40
0 40 80 120 160
SOA (ms)
No ISI
With ISI
tgt mskISI
tgt msk
With ISI
No ISI
Function of SOA, not ISI (SOA law)
NOTE: no masking when SOA = 0
![Page 71: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/71.jpg)
A theory of metacontrast masking:
Cross-Channel Inhibition
(Breitmeyer & Ganz, 1976, 2005)
![Page 72: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/72.jpg)
1. A brief display generates activity in two visual channels:a) Transient channels (short latency; short duration; low SF; mediate perception of stimulus onset)b) Sustained channels (long latency; long duration; high SF; mediate perception of stimulus identity)
2. Activity in the transient channels suppresses activity in the sustained channels
mask
target
time
+ +
no masking when SOA = 0
![Page 73: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/73.jpg)
target
mask
time
1. A brief display generates activity in two visual channels:a) Transient channels (short latency; short duration; mediate perception of stimulus onset)b) Sustained channels (long latency; long duration; mediate perception of stimulus identity)
2. Activity in the transient channels suppresses activity in the sustained channels
![Page 74: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/74.jpg)
Support for the cross-channel inhibition hypothesis
inhibition vanishes in scotopic viewing (von Békésy)and so does metacontrast masking
Light-adapted Dark-adapted
![Page 75: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/75.jpg)
Masking of a pattern by parts of itself reveals a new form of masking:Object substitution
F1 F2
(30 ms) (300 ms)
Demo:mat2 0-2-0mat2 0-2-20(vary overlap)
F2
F1
F2
![Page 76: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/76.jpg)
This is unquestionably a form of masking but:
The mask consists of a portion of the target
The target-”mask” SOA is equal to zero
Remember: no metacontrast masking when SOA = 0
So, let’s turn this into a classical metacontrast paradigm,and see if masking occurs when SOA = 0
![Page 77: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/77.jpg)
target mask
Metacontrast paradigm
time
SOA = 0
![Page 78: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/78.jpg)
0
demo
![Page 79: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/79.jpg)
1x
![Page 80: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/80.jpg)
2x
![Page 81: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/81.jpg)
3x
![Page 82: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/82.jpg)
4x
![Page 83: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/83.jpg)
The finding that metacontrast masking occurs when T-M SOA = 0is inconsistent with accounts based on
inhibitory contour interactions
+ +
![Page 84: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/84.jpg)
In addition,common-onset masking
occurs without substantial masking contours
(four-dot masking)
![Page 85: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/85.jpg)
1dotx
![Page 86: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/86.jpg)
2dotx
![Page 87: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/87.jpg)
3dotx
![Page 88: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/88.jpg)
4dotx
![Page 89: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/89.jpg)
Common-onset masking occurs with overlearned geometrical shapes
![Page 90: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/90.jpg)
The target can be seen easily when theentire display is presented briefly
(10 ms)
![Page 91: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/91.jpg)
os16-0a
![Page 92: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/92.jpg)
os16-0b
![Page 93: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/93.jpg)
os16-0c
![Page 94: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/94.jpg)
os16-0d
![Page 95: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/95.jpg)
Display sequence forobject-substitution masking
(320 ms)
(10 ms)
![Page 96: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/96.jpg)
os16-600a
![Page 97: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/97.jpg)
os16-600b
![Page 98: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/98.jpg)
os16-600c
![Page 99: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/99.jpg)
os16-600d
![Page 100: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/100.jpg)
How does object substitutioncome about?
![Page 101: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/101.jpg)
?
![Page 102: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/102.jpg)
Object-substitution masking does not occur when set size = 1
(320 ms)
(10 ms)
![Page 103: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/103.jpg)
os1-600a
![Page 104: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/104.jpg)
os1-600b
![Page 105: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/105.jpg)
os1-600c
![Page 106: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/106.jpg)
os1-600d
![Page 107: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/107.jpg)
Object substitution masking does not occurwhen attention is directed to the target location
![Page 108: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/108.jpg)
os16-600a
X
![Page 109: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/109.jpg)
os16-600b
X
![Page 110: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/110.jpg)
Expectation based on learned regularities(occlusion of far objects by near objects)
influences OSMKahan & Lichtman (P&P, in press)
30 ms
time
600 ms
![Page 111: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/111.jpg)
Expectation based on learned regularities(occlusion of far objects by near objects)
influences OSMKahan & Lichtman (P&P, in press)
nearfar
0
4
2
8
6
10
-2
Mask
ing E
ffect
% C
(co
mm
on -
dela
yed o
ffse
t)
n-n f-f f-n n-fTarget-mask depth
![Page 112: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/112.jpg)
Common-onset masking has two components
Inhibitory contour interactions
early
photopic
independent of attention
requires substantial masking contours
does not occur at SOA = 0
Object-substitution
relatively late
scotopic
critically dependent on attention
requires minimal masking contours
occurs at SOA = 0
?
![Page 113: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/113.jpg)
Duration of mask (ms)
% c
orr
ect
resp
on
ses
0 80 160 240 320
20
40
60
80
100
Set Size(No. elements)
1 2 4 816
Photopic
0 80 160 240 320
60
80
100
Scotopic
Separating the two components of common-onset masking:(inhibitory contour interactions and object substitution)
![Page 114: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/114.jpg)
Separating the two components of common-onset masking:(inhibitory contour interactions and object substitution)
photopic
scotopic
![Page 115: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/115.jpg)
Masking occurs in two main flavours:a) integration (camouflage)b) interruption: i) metacontrast masking ii) pattern masking iii) object-substitution masking
![Page 116: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/116.jpg)
Pattern masking is probably the most commonly used form of maskingbut, in my opinion, it is the least interesting
Depending on viewing conditions, it includes aspects of bothintegration and object substitution
![Page 117: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/117.jpg)
Here is one way in which the processes of integration and interruption(object substitution) may combine to yield masking
(Michaels & Turvey, 1979)
![Page 118: Masking occurs when the perception of a brief stimulus (the target) is impaired by another stimulus (the mask) presented in close temporal and spatial.](https://reader038.fdocuments.us/reader038/viewer/2022103112/551b58a5550346d31b8b5435/html5/thumbnails/118.jpg)
… e co
sì via…
… u
nd so w
eiter …
… and so
on …
Ciao!
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