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. Author manuscript; available in PMC: 2009 Apr 21.
Published in final edited form as: Exp Brain Res. 2008 Feb 28;187(4):535–549. doi: 10.1007/s00221-008-1322-z

Table 2.

Fitting parameters to quantify the influence of the context bar and the influence of attention on orientation discrimination

High contrast
Medium contrast
Low contrast
Subject n
g
Subject n
g
Subject n
g
Single task Dual task Single task Dual task Single task Dual task Single task Dual task Single task Dual task Single task Dual task
KW 0.22 9.45 -0.43 -0.77 CP 1.24 0.15 -0.22 -0.21 MR 0.97 12.85 -0.02 0.07
WS 22.61 16.12 -0.10 -0.59 DC 0.31 3.99 -0.33 -1.04 NT 4.70 5.67 -0.09 0.57
CS 12.20 0.14 -0.12 -0.43 SJH 0.12 0.56 -0.27 -0.54 YL 9.11 7.91 0.26 0.21
DB 13.37 7.61 -0.24 -0.25 TE 0.05 1.01 -0.43 -0.46 ZI 5.65 5.59 0.22 0.36
AT 19.38 0.52 -0.22 -0.35 EA 8.26 1.31 0.31 0.34
AG 12.39 6.92 -0.32 -0.45 IS 8.42 3.42 0.06 0.33
DH 0.21 5.59 -0.34 -0.34 ER 5.48 5.15 0.54 0.78
JS 0.18 0.14 -0.30 -0.74
NT 4.36 0.34 0.00 -0.08
YL 12.33 6.98 -0.17 -0.07
BP 3.00 0.01 -0.45 -0.88
PA 5.57 0.31 -0.28 -0.37
HS 1.71 0.03 -0.13 -0.27
Median 5.57 0.52 -0.24 -0.37 Median 0.21 0.78 -0.30 -0.50 Median 5.65 5.59 0.22 0.34
25th 1.71 0.14 -0.32 -0.59 25th 0.10 0.45 -0.35 -0.67 25th 5.09 4.29 0.02 0.27
75th 12.39 6.98 -0.13 -0.27 75th 0.54 1.75 -0.26 -0.40 75th 8.34 6.79 0.29 0.46
SRT P = 0.06 P = 0.002 SRT P = 0.63 P = 0.25 SRT P = 0.58 P = 0.047
SRT P = 0.06 P < 0.0001
 Comp

Parameters were obtained by fitting a tilted 3D surface to the data (for details see “Results” and “Methods”). The parameter “n” corresponds to the slope of the surface along the target-to-reference axis and so relates to the reliability of the response. The parameter “g” corresponds to the gradient of the surface along the target-to-context bar axis and so relates to the effect of the context bar on the perceived target orientation. Lower rows give the median, 25th and 75th percentiles over the population. P-values indicate whether a significant difference for the parameter of interest occurred between single and dual task for each contrast condition separately (signed rank test SRT) and for all contrasts combined (SRT Comb.)