Here, we have tested to what extent the overall configuration plays a role in crowding by dissecting uncrowding configurations systematically. First, we reproduced previous findings of uncrowding with an increasing number of elements. Performances in the 35 square grid condition were about at the same level as in the Vernier alone condition (
Figure 2f). Importantly, despite minor differences, uncrowding occurs for both the horizontal and vertical arranged flankers, also for horizontal and vertical Vernier targets (
Figures 2 and
3). Note that, unlike previous work (
Manassi et al., 2013;
Manassi et al., 2016), the three horizontally aligned squares did not show a clear performance improvement compared to the single square condition. We do not have an explanation for this beyond noises. The oblique configuration showed a different behavioral pattern (
Figure 4). For example, increasing the number of squares in one of the ±45° orientations did not improve performance (
Figure 4, conditions a vs. c, e, and g, or conditions a vs. b, d, and f). Surprisingly, when the entire 35-square grid was presented, the performance was as good as for the cardinal orientations (
Figure 4h left & right, 35-square grid condition).
Livne and Sagi (2011) showed that obliquely oriented and positioned flankers crowd stronger than cardinally oriented flankers. In addition, the obliquely presented stimuli made various visual tasks significantly harder, including orientation discrimination (
Bouma & Andriessen, 1968), orientation discrimination under crowding (
Livne & Sagi, 2011), Vernier discrimination (
Saarinen & Levi, 1995;
Westheimer, 2005), motion discrimination (
Ball & Sekuler, 1982;
Coletta, Segu, & Tiana, 1993), orientation detection (
Attneave & Olson, 1967), and more, likely because of neuronal preferences of cardinal orientations in low-level visual areas (
Bauer et al., 1979;
Furmanski & Engel, 2000;
Li et al., 2003;
Xu et al., 2006). Hence, similarly, we expected performance would deteriorate with the oblique flankers while keeping crowding characteristics similar to the cardinal flankers. However, the results were not as expected. There was no performance improvement (uncrowding) when increasing the number of squares in either ±45 orientations but only with the 35-square grid (
Figure 4). This may be because the grouping cue was too weak with three, five, or seven squares for one of the ±45° orientations. Nevertheless, when a stronger grouping cue was provided by the grid of 35 squares, performance was good (uncrowding) regardless of orientation, approaching the performance in Vernier alone conditions (and comparable to the cardinal stimuli's performance). Therefore our results once again argue for complex spatial interactions, which most existing models cannot capture easily.