Covert attention eliminates temporal disparities in the

visual field

Marisa Carrasco, Anna Marie Giordano& Brian McElree

New York University

SAT provides separate measures of discriminability and speed of processing.

• memory retrieval Dosher, Cognit. Psychol. 76; Ratcliff & McKoon,

Cognit. Psychol. 89; Wickelgren, Acta Psychol. 77 • short-term memory

McElree & Dosher, JEP:Gen. 89; Reed, Science 76

• visual search McElree & Carrasco, JEP:HPP 99

SAT (speed-accuracy trade-off) procedure

Covert attention improves discriminability and speeds information accrual.

Carrasco & McElree, PNAS 01

What about speed of processing?

Does covert attention differentially affect the speed of processing at different eccentricities?

• Attention increases sensitivity and resolution more so at peripheral locations but to the same degree at isoeccentric locations.

• Discriminability varies across eccentricity and isoeccentric locations.

goals

SAT functionsExponential Parameter Estimates [ d’(t) = (1-e - (t-)), for t > , else 0 ]

asymptote

rate

intercept

Fixation point (1000 ms)

• 3 naïve observers (eccentricity); 5 naïve observers (location)• set size: 1 & 8• 2 AFC - orientation discrimination (30º tilt) @ 4,7,& 9º eccentricity• SOA = 120 ms• precue onset to display offset = 160 ms

Time

Precue (67 ms)

Neutral cue Peripheral cue

ISI (53 ms)

Display (40 ms)

Feature

Response tone (40, 94, 200, 350, 600,

1000 & 2000 ms)

trial sequence

results - neutral

Speed of processing faster with increasing eccentricity;cortical magnification accounts for ~1/2 the difference.

Carrasco, McElree, Denisova & Giordano, Nature Neurosci. 03

Attentional effect is similar at different eccentricities.

results - peripheral

S100% 100% 100% 100%

neutralcue

N

W E

peripheralcue

Performance is not homogenous across the visual field.

horizontal-vertical anisotropy & vertical meridian asymmetry

more pronounced with: set size, spatial frequency, eccentricity

performance fields

visual, not attentional, constraints Carrasco, Talgar & Cameron, Sp. Vis. 01; Cameron, Tai & Carrasco, Vis.

Res. 02

N

neutral 471 ms

E

S

W neutral 412 msneutral 409 ms

information accrual at different locations - 4 ecc(combined +-1 in ms)

NENW

SESW

Hierarchical model testing 4 asypmtotes: cue type & set size1 rate: all2 intercepts: cue type

neutral 430 msneutral 443 ms

neutral 439 ms neutral 435 ms

neutral 444 msperipheral 380 ms

peripheral 380 ms

peripheral 381 ms

peripheral 386 ms

peripheral 397 ms

peripheral 386 ms

peripheral 382 ms

peripheral 364 ms

N

E

S

neutral 520 ms

W neutral 470 msneutral 483 ms

information accrual at different locations - 7 ecc

NENW

SESW

neutral 530 msneutral 501 ms

neutral 489 msneutral 462 ms

NSS1 0.66 PSS1 1.10NSS8 0.50 PSS8 0.74

peripheral 450 ms

peripheral 456 ms peripheral 465 ms

peripheral 440 ms

peripheral 461 ms

peripheral 439 ms

peripheral 408 ms

?Neutral Peripheral

N

E

S

neutral 610 ms

W neutral 459 msneutral 521 ms

information accrual at different locations - 9 ecc

NENW

SESW

neutral 481 msneutral 503 ms

neutral 447 msneutral 562 ms

NSS1 0.93 PSS1 1.40NSS8 0.60 PSS8 1.44

peripheral 459 ms

peripheral 471 ms

peripheral 445 ms

peripheral 496 ms

peripheral 404 ms

peripheral 418 ms

peripheral 450 ms

?Neutral Peripheral

Exponential Parameter Estimates [ d’(t) = (1-e - (t-)), for t > , else 0 ]

neutral – set size 1

350

600

Time (ms)

Location

% A

sym

ptot

e

450

00

35

40

50

60

8080

90

90

9090

Exponential Parameter Estimates [ d’(t) = (1-e - (t-)), for t > , else 0 ]

peripheral – set size 1

300Time (ms)

Location

% A

sym

ptot

e

450

1010

3030

80

8080

80

2. differs at isoeccentric locations

2. effects are different isoeccentric locations eliminating speed differences across them

conclusions

1. increases with increasing eccentricity Carrasco, McElree, Denisova & Giordano, Nature Neurosci. 03

Speed of processing:

Attention:

1. effects are similar at different eccentricities

N-8

N-1 P-1

P-8

information accrual at different locations - 7º ecc

NW NSS1 2.33 PSS1 2.71NSS8 1.85 PSS8 2.48

Neutral 501 msPeripheral 456 ms

NNSS1 0.66 PSS1 1.10NSS8 0.50 PSS8 0.74

Neutral 479 msPeripheral 458 ms

NENSS1 2.41 PSS1 2.64NSS8 2.04 PSS8 2.70

Neutral 481 msPeripheral 450 ms

S

NSS1 1.63 PSS1 1.95NSS8 1.67 PSS8 1.95

Neutral 520 msPeripheral 439 ms

W

NSS1 2.66 PSS1 2.85NSS8 2.40 PSS8 2.71

Neutral 483 msPeripheral 450 ms

SW

NSS1 2.16 PSS1 2.76NSS8 1.90 PSS8 2.76

Neutral 462 msPeripheral 408 ms

SE

NSS1 2.39 PSS1 2.87NSS8 2.18 PSS8 2.90

Neutral 447 msPeripheral 404 ms

ENSS1 2.50 PSS1 2.77NSS8 2.12 PSS8 2.67

Neutral 459 msPeripheral 418 ms

information accrual at different locations - 9 ecc

NW NSS1 1.96 PSS1 2.20NSS8 1.45 PSS8 2.31

Neutral 503 msPeripheral 459 ms

NNSS1 0.93 PSS1 1.40NSS8 0.60 PSS8 1.44

Neutral 467 msPeripheral 500 ms

NENSS1 1.97 PSS1 2.49NSS8 1.71 PSS8 2.39

Neutral 530 msPeripheral 465 ms

S

NSS1 0.91 PSS1 1.41NSS8 0.71 PSS8 1.53

Neutral 610 msPeripheral 496 ms

W

NSS1 2.63 PSS1 2.60NSS8 1.97 PSS8 2.47

Neutral 521 msPeripheral 471 ms

SW

NSS1 2.20 PSS1 2.47NSS8 1.46 PSS8 2.40

Neutral 562 msPeripheral 445 ms

SE

NSS1 2.15 PSS1 2.33NSS8 1.78 PSS8 2.37

Neutral 489 msPeripheral 461 ms

ENSS1 2.52 PSS1 2.55NSS8 2.22 PSS8 2.36

Neutral 470 msPeripheral 440 ms