Figure 3d shows the comparisons of the post- versus pretraining and the comparisons of swapped versus pretraining SOA thresholds respectively for all observers. Interestingly, we observed that the detection of an oblique target against cardinal backgrounds (e.g., B91°/T75° or B181°/T165°) was more efficient than the reverse scenario (e.g., B75°/T91° or B165°/T181°), as the orientation search asymmetry reported by
Yashar and Denison (2017). Specifically, three observers trained with B91°/T75° or B181°/T165° showed little transfer to the swapped situations B75°/T91° or B165°/T181°, Threshold
pre_ B91°
/T75° = 254.7 ± 27.8 ms, Threshold
post_ B91°
/T75° = 57.0 ± 10.4 ms, Threshold
swapped_ B75°
/T91° = 189.7 ± 49.7 ms; Threshold
pre_ B181°
/T165° = 410.0 ± 142.1 ms, Threshold
post_ B181°
/T165° = 54.3 ± 18.8 ms, Threshold
swapped_ B165°
/T181° = 400.0 ± 42.6 ms. Conversely, five observers trained with B75°/T91° or B165°/T181° showed complete transfer to the swapped situations B91°/T75° or B181°/T165°, Threshold
pre_ B75°
/T91° = 491.3 ± 66.3 ms, Threshold
post_ B75°
/T91° = 199.2 ± 37.9 ms, Threshold
swapped_ B91°
/T75° = 118.9 ± 37.4 ms; Threshold
pre_ B165°
/T181° = 793.0 ± 205.4 ms, Threshold
post_ B165°
/T181° = 185.6 ± 52.0 ms, Threshold
swapped_ B181°
/T165° = 118.2 ± 36.2 ms. These results confirmed the results reported by
Yashar and Denison (2017), showing the transfer depending on the orientation of the target, with full transfer of learning from near-cardinal to oblique targets, but not the reverse.