All participants performed above chance in all conditions (average performance in audio: 77.25% [9.01%] and in visual: 89.33% [6.12%]). Using our criteria, we excluded 5.09% (.64%) of responses—number of items removed did not vary across conditions, auditory: F1(4, 216) = 1.973, p = .10, visual: F1(4, 216) = 1.132, p = .342.
Auditory task
Orthographic and phonological similarity effects
For A’ in the auditory modality, we found a main effect of phonological similarity by participant, such that high phonological similarity led to higher signal detection (M = .86, SD = .07) than low similarity (M = .84, SD = .09), F1(1, 54) = 18.349, p < .001, ηp2 = .254; by item, this phonological effect was not significant, F2(1, 196) = .478, p = .490, ηp2 = .002. There was also a main effect of orthographic similarity by participants, such that high orthographic similarity led to lower signal detection (M = .85, SD = .08) than low similarity (M = .86, SD = .08), F1(1, 54) = 6.211, p = .016, ηp2 = .103 (no effect by item, F2(1, 196) = 1.273, p = .261, ηp2 = .006). Finally, there was no interaction between the two factors, F1(1, 54) = .838, p = .364, ηp2 = .015, F2(1, 196) = .518, p = .472, ηp2 = .003. See Table 2 and Figure 2 for by-subject statistics.
For response time in the auditory modality, we found no main effect of phonological similarity, F1(1, 54) = 1.707, p = .197, ηp2 = .031, F2(1, 296) = .721, p = .396, ηp2= .002. There was a main effect of orthographic similarity, such that high orthographic similarity led to longer reaction times (M = 445.84, SD = 102.99) than low similarity (M = 428.83, SD = 98.29), F1(1, 54) = 12.078, p < .001, ηp2 = .183 (marginally significant by stimulus, F2(1, 196) = 2.840, p = .094, ηp2= .014). Finally, there was no interaction between the two factors, F1(1, 54) = 1.360, p = .249, ηp2 = .025, F2(1, 196) = .558, p = .456, ηp2 = .003. See Table 2 and Figure 2 for by-subject statistics.
Table 2: By-subject means and standard deviations
Orthographic similarity
|
Low
|
High
|
Identical
|
Phonological similarity
|
Low
|
High
|
Low
|
High
|
High
|
Auditory
|
A'
|
0.85 (0.10)
|
0.86 (0.07)
|
0.83 (0.09)
|
0.86 (0.08)
|
0.86 (0.09)
|
RT (ms)
|
429.78 (108.98)
|
427.89 (94.80)
|
452.36 (109.14)
|
439.32 (103.00)
|
480.01 (104.12)
|
Visual
|
A'
|
0.94 (0.05)
|
0.93 (0.05)
|
0.94 (0.04)
|
0.94 (0.04)
|
0.96 (0.03)
|
RT (ms)
|
670.63 (71.87)
|
683.38 (77.88)
|
670.63 (71.87)
|
673.83 (74.23)
|
626.78 (70.26)
|
Note: Numbers in parentheses are standard deviations. The N in all cases is 55.
Identical orthography items (orthographically identical words)
For A’ in the auditory modality, we found no effects of orthographic similarity in the by-subject analysis, F1(2, 108) = .732, p = .483, ηp2 = .013, nor in the by-item analysis, F2(2, 147) = .037, p = .963, ηp2 < .001.
In the response time analysis, we found an effect of orthographic similarity, F1(2, 108) = 25.801, p < .001, ηp2 = .323, F2(2, 147) = 5.6730, p = .004, ηp2 = .072. In the by-subject post-hoc tests, we found that identical items (M = 480.01, SD = 104.12) were responded to slower than both high similarity (M = 439.32, SD = 104.00), t(54) = 5.865, p < .001, Cohen’s D = .791, and low similarity items (M = 427.89, SD = 94.80), t(54) = 6.102, p < .001, Cohen’s D = .823, but high and low similarity items did not differ, t(54) = 1.563, p = .371, Cohen’s D = .211. See table 2 and Figure 3 for by-subject means and standard deviations. Similarly, regarding the by-item analysis, in the post-hoc tests, we observed that identical items (M = 506.62, SD = 93.68) were responded to slower than both high (M = 458.89, SD = 103.37), t(54) = 2.507, p = .040, Cohen’s D = .484, and low similarity items (M = 445.26, SD = 87.87), t(54) = 3.224, p = .005, Cohen’s D = .676, but high and low similarity items did not differ, t(54) = -.716, p = 1, Cohen’s D = .142.
Visual task
Orthographic and phonological similarity
For A’ in the visual modality, there was a main effect of orthographic similarity, F1(1, 54) = 4.962, p = .030, ηp2 = .084, such that high orthographic similarity led to higher signal detection (M = .94, SD = .04) than low similarity (M = .93, SD = .05). In the by-item analysis, we did not find this orthographic similarity effect, F2(1, 196) = .434, p = .511, ηp2 = .002. We found a marginal main effect of phonological similarity in the by subject analysis, F1(1, 54) = 2.982, p = .090, ηp2 = .052, such that high phonological similarity tended to led to lower signal detection (M = .93, SD = .04) than low similarity (M = .94, SD = .04)(no effect in the by-item analysis, F2(1, 196) = .072, p = .788, ηp2 < .001). Finally, there was no interaction between the two factors, F1(1, 54) = 1.896, p = .174, ηp2 = .034, F2(1, 196) = .143, p = .706, ηp2 < .001. See Table 2 and Figure 4 for by-subject statistics.
For response times in the visual modality, there was no main effect of orthographic similarity, F1(1, 54) = 2.319, p = .134, ηp2 = .041, F2(1, 196) = 1.033, p = .311, ηp2 = .005. We found a main effect of phonological similarity in the by-subject analysis, F1(1, 54) = 6.889, p = .011, ηp2 = .113, such that high phonological similarity led to slower response times (M = 678.60, SD = 73.97) than low similarity (M = 669.87, SD = 71.47), (no effect in the by stimulus analysis, F2(1, 196) = 2.484, p = .117, ηp2 = .012). There was also no interaction between the two factors, F1(1, 54) = 1.946, p = .169, ηp2 = .035, F2(1, 196) = .902, p = .343, ηp2 = .005. See Table 2 and Figure 4 for by-subject statistics.
Identical orthography items (Orthographically identical words)
There was an effect of orthographic similarity on A’, F1(2, 95.304) = 32.325, p < .001, ηp2 = .374, F2(2, 147) = 6.204, p = .003, ηp2 = .078. In the post-hoc tests, we found that identical items had higher signal detection (M = .96, SD = .03) than both high similarity items (M = .94, SD = .04), t(54) = 6.535, p < .001, Cohen’s D = .881, and low similarity items(M = .93, SD = 05) , t(54) = 6.699, p < .001, Cohen’s D = .903. High similarity items also had higher signal detection than low similarity items, t(54) = 2.274, p = .081, Cohen’s D = .307—see Table 2 and Figure 5 for by-subject statistics.
We found an effect of orthographic similarity on response time, F1(2, 108) = 75.689, p < .001, ηp2 = .584, F2(2, 147) = 25.164, p < .001, ηp2 = .255. In the post-hoc tests, we found identical items were recognized faster (M = 626.78, SD = 70.26) than both high (M = 673.83, SD = 74.23), t(54) = 10.430, p < .001, Cohen’s D = 1.406, and low similarity items (M = 683.38, SD = 77.88), t(54) = 10.426, p < .001, Cohen’s D = 1.406, but high and low similarity items did not differ, t(54) = 1.994, p = .154, Cohen’s D = .269—see Table 2 and Figure 5 for by-subject statistics.