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Covert attention eliminates temporal disparities in the visual field Marisa Carrasco, Anna Marie Giordano & Brian McElree New York University.

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Presentation on theme: "Covert attention eliminates temporal disparities in the visual field Marisa Carrasco, Anna Marie Giordano & Brian McElree New York University."— Presentation transcript:

1 Covert attention eliminates temporal disparities in the visual field Marisa Carrasco, Anna Marie Giordano & Brian McElree New York University

2 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

3  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

4 SAT functions Exponential Parameter Estimates [ d’(t) = (1-e -  (t-  ) ), for t > , else 0 ] asymptote   rate   intercept

5 Fixation point (1000 ms) 3 naïve observers (eccentricity); 5 naïve observers (location) set size: 1 & 8 2 AFC - orientation discrimination (30º 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

6 results - neutral Speed of processing faster with increasing eccentricity; cortical magnification accounts for ~1/2 the difference. Carrasco, McElree, Denisova & Giordano, Nature Neurosci. 03

7 Attentional effect is similar at different eccentricities. results - peripheral

8 S 100% neutral cue N W E peripheral cue 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

9 N neutral 471 ms E S W neutral 412 ms neutral 409 ms information accrual at different locations - 4  ecc (combined  +  -1 in ms) NE NW SE SW Hierarchical model testing 4 asypmtotes: cue type & set size 1 rate: all 2 intercepts: cue type neutral 430 ms neutral 443 ms neutral 439 ms neutral 435 ms neutral 444 ms peripheral 380 ms peripheral 381 ms peripheral 386 ms peripheral 397 ms peripheral 386 ms peripheral 382 ms peripheral 364 ms

10 N E S neutral 520 ms W neutral 470 ms neutral 483 ms information accrual at different locations - 7  ecc NE NW SE SW neutral 530 ms neutral 501 ms neutral 489 ms neutral 462 ms NSS PSS NSS PSS peripheral 450 ms peripheral 456 ms peripheral 465 ms peripheral 440 ms peripheral 461 ms peripheral 439 ms peripheral 408 ms ? Neutral Peripheral

11 N E S neutral 610 ms W neutral 459 ms neutral 521 ms information accrual at different locations - 9  ecc NE NW SE SW neutral 481 ms neutral 503 ms neutral 447 ms neutral 562 ms NSS PSS NSS PSS peripheral 459 ms peripheral 471 ms peripheral 445 ms peripheral 496 ms peripheral 404 ms peripheral 418 ms peripheral 450 ms ? Neutral Peripheral

12 Exponential Parameter Estimates [ d’(t) = (1-e -  (t-  ) ), for t > , else 0 ] neutral – set size Time (ms) Location % Asymptote

13 Exponential Parameter Estimates [ d’(t) = (1-e -  (t-  ) ), for t > , else 0 ] peripheral – set size Time (ms) Location % Asymptote

14 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

15 N-8 N-1 P-1 P-8

16 information accrual at different locations - 7 º ecc NW NSS PSS NSS PSS Neutral 501 ms Peripheral456 ms N NSS PSS NSS PSS Neutral 479 ms Peripheral458 ms NE NSS PSS NSS PSS Neutral 481 ms Peripheral450 ms S NSS PSS NSS PSS Neutral 520 ms Peripheral439 ms W NSS PSS NSS PSS Neutral 483 ms Peripheral450 ms SW NSS PSS NSS PSS Neutral 462 ms Peripheral408 ms SE NSS PSS NSS PSS Neutral 447 ms Peripheral404 ms E NSS PSS NSS PSS Neutral 459 ms Peripheral418 ms

17 information accrual at different locations - 9  ecc NW NSS PSS NSS PSS Neutral 503 ms Peripheral459 ms N NSS PSS NSS PSS Neutral 467 ms Peripheral500 ms NE NSS PSS NSS PSS Neutral 530 ms Peripheral465 ms S NSS PSS NSS PSS Neutral 610 ms Peripheral496 ms W NSS PSS NSS PSS Neutral 521 ms Peripheral471 ms SW NSS PSS NSS PSS Neutral 562 ms Peripheral445 ms SE NSS PSS NSS PSS Neutral 489 ms Peripheral461 ms E NSS PSS NSS PSS Neutral 470 ms Peripheral440 ms


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