**3. Results**

## *3.1. Target Identification*

Percentages of trials in which the targets were identified are displayed in Figure 2. Additionally, mean values and standard deviations are compiled in the Table S1 (see Supplementary Materials). Each data point was computed from 25 trials per participant.

#### 3.1.1. T1: Trials without Lures

T1 was identified in 84% of no-lure trials on average (black line in the upper left panel of Figure 2). No-lure identification rates were submitted to ANOVA with the factors T1 Side (left, right) and T2 Side (same as T1, other than T1). T1 was identified better when the following T2 was in the same stream and T1 was on the right (R*3R* in Figure 2, with absence of italics denoting the target under consideration, here T1), as indicated by a main effect of T2 Side, *<sup>F</sup>*1,13 = 9.4, *p* = 0.009, and the interaction of T2 Side × T1 Side *<sup>F</sup>*1,13 = 4.5, *p* = 0.05, resolved to an effect of T2 Side for right T1, *<sup>F</sup>*1,13 = 11.8, *p* = 0.004, and no such effect for left T1, *<sup>F</sup>*1,13 = 1.2, n.s.

Additionally, the other-side-than-T2 data were compared between lag 3 and lag 1 in an ANOVA with the factors T1 Side (left, right) and Lag (1, 3). No effect was significant, all *<sup>F</sup>*1,13 ≤ 2.1, *p* ≥ 0.17.

**Figure 2.** Lure effects on identification rates of T1 and T2. The upper panels display the percentages of trials in which T1 (left) and T2 (right) were identified. The lower panels display the differences between trials with lures from trials without lures. No-lure trials (upper panels only) are denoted by black lines, trials with digit lures by grey lines, and trials with color lures by blue lines. Trials where lures were in the same stream as the target (T1 and T2, respectively) are denoted by solid lines (grey and blue) and trials where lures were in the opposite stream are denoted by dashed lines. Both for T1 and T2, the six values on the x axes denote left-right-left-right-left-right targets. E.g., "L1R" is a trial where T1 was left and T2 was right (separated from each other by 1 frame). Thereby, L1R is the leftmost value for T1 (L*1R*) and the second value for T2 (*L1*R). The main ANOVAs were conducted on the lag 3 data (four rightmost values in each panel) and additional ANOVAs compared lag 1 and lag 3 other-target-on-other-side data (two leftmost and two rightmost values in each panel).

#### 3.1.2. Lure Effects on T1 Identification

Lure effects were tested by subtracting the no-lure data from data of each of the four conditions with lures and entering these differences to ANOVAs. The main ANOVA was conducted on lag 3 trials with the repeated-measurement factors Lure Type (digit, color) and Lure Side (same as T1, other than T1), additionally to T1 Side and T2 Side. ANOVA results are compiled in Table 1.



Degrees of freedom are 1,13 throughout. *F* and *p* values are printed in bold when *p* ≤ 0.050. *p*-values were entered when *p* ≤ 0.10.

Color lures had larger negative effects on T1 identification than digit lures (blue vs. grey in Figure 2), Lure Type *<sup>F</sup>*1,13 = 5.1, *p* = 0.04, and lure effects were more negative when the following T2 was on the same side as T1 (L*3L* and R*3R*) than when sides changed (L*3R* and R*3L*), T2 Side *<sup>F</sup>*1,13 = 9.1, *p* = 0.01.

When lures, T1, and T2 all were in one stream (solid blue and grey lines in Figure 2), right-side T1 was more affected by lures than left-side T1 (*r*R*3R* > *l*L*3L*): Lure Side × T1 Side × T2 Side *<sup>F</sup>*1,13 = 7.5, *p* = 0.02, resolved to an effect of T1 Side × T2 Side of *<sup>F</sup>*1,13 = 6.7, *p* = 0.02, for lures on the same side as T1 (in contrast to *<sup>F</sup>*1,13 = 1.0, n.s., for lures on other side than T1) and further, for these same-side lures, to an effect of T1 Side of *<sup>F</sup>*1,13 = 10.1, *p* = 0.007, when T2 was on same side as T1 (in contrast to *<sup>F</sup>*1,13 = 0.7, n.s., for T2 on the other side than T1).

Finally, the significant four-fold interaction (T1 Side × Lure Side × Lure Type × T2 Side *<sup>F</sup>*1,13 = 6.9, *p* = 0.02) reflected two separate effects, namely, first, the outlying positive value of the dashed grey line in Figure 2 at R*3L* and, second, the outlying negative value of the dashed blue line at L*3L*. To detail: The outlying positive value of the dashed grey line at R*3L* was reflected by resolving the fourfold interaction to threefold interactions of Lure Type × T1 Side × T2 Side separately for same-side and other-side lures, which yielded a significant result for other-side lures (dashed lines in Figure 2), *<sup>F</sup>*1,13 = 14.2, *p* = 0.002, in contrast to *<sup>F</sup>*1,13 = 0.9, n.s., for same-side lures. Then resolving that threefold interaction for other-side lures to effects of T1 Side for each of the four combinations of Lure Type × T2 Side yielded a significant effect of T1 Side for digit lures and other-side T2 (dashed grey line: R*3L* more positive than L*3R*), *<sup>F</sup>*1,13 = 9.1, *p* = 0.01, in contrast to *<sup>F</sup>*1,13 ≤ 0.7, n.s., for each of the other three combinations. Second, the outlying negative value of the dashed blue line at L*3L* was reflected by resolving the overall fourfold interaction to threefold interactions of Lure Side × T1 Side × T2 Side separately for color lures and digit lures which yielded a significant result for color lures, *<sup>F</sup>*1,13 = 12.5, *p* = 0.004, in contrast to digit lures, *<sup>F</sup>*1,13 = 0.0, n.s. Resolving that threefold interaction for color lures to effects of Lure Side for each of the four combinations of T1 Side × T2 Side yielded a significant effect of Lure Side for L*3L*—other side (dashed blued line in Figure 2) more negative than same-side (solid blue line)—, *<sup>F</sup>*1,13 = 8.9, *p* = 0.01, in contrast to the other three combinations of T1 Side × T2 Side (R*3R*, L*3R*, R*3L*), *<sup>F</sup>*1,13 ≤ 2.5, *p* ≥ 0.15, n.s.

A second ANOVA was run to compare other-side-than-T2 data between lag 3 (L*3R*, R*3L*) and lag 1 (L*1R*, R*1L*), replacing the previous factor T2 Side by Lag (lag 1, lag 3) to have the factors Lure Type, Lure Side, T1 Side, and Lag. No effect of Lag reached significance, all *<sup>F</sup>*1,13 ≤ 2.8, *p* ≥ 0.12.

#### 3.1.3. T2: Trials without Lures

T2 was identified in 61% of no-lure trials on average. Similar to T1 analysis, ANOVA on no-lure rates of T2 identification in lag 3 trials had the factors T2 Side (left, right) and T1 Side (same as T2, other than T2). Left T2 was identified better than right T2, *<sup>F</sup>*1,13 = 7.5, *p* = 0.02. T2 on the same side as T1 was better identified than T2 on the other side, *<sup>F</sup>*1,13 = 10.3, *p* = 0.007. These two factors did not interact, *<sup>F</sup>*1,13 = 0.3, n.s.).

Additionally, the lag 1 data were compared to the other-side-than-T1 data of lag 3 in an ANOVA with the factors T2 Side (left, right) and Lag (1, 3). T2 tended to be better identified after Lag 3 than after Lag 1, *<sup>F</sup>*1,13 = 4.3, *p* = 0.06. The advantage of left T2 over right T2 was again significant, *<sup>F</sup>*1,13 = 5.4, *p* = 0.04, and did not interact with Lag, *<sup>F</sup>*1,13 = 0.3, n.s.

#### 3.1.4. Lure Effects on T2 Identification

Like with T1, the main ANOVA on differences between lure and no-lure trials was conducted on lag 3 trials, with the factors Lure Type (digit, color) and Lure Side (same as T2, other than T2), additionally to T1 Side (same as T2, other than T2) and T2 Side (left, right). ANOVA results are compiled in the top half of Table 2.

As predicted, color lures were much more detrimental than digit lures, *<sup>F</sup>*1,13 = 27.5, *p* < 0.001. Besides, the pattern of effects differed much between color lures and digit lures (Figure 2), as reflected

by five out of seven possible interactions of Lure Type being significant (top half of Table 2). Therefore, separate ANOVAs were computed for the two lure types, with the factors Lure Side, T1 Side, and T2 Side (bottom half of Table 2).


**Table 2.** ANOVA effects on lure effects (deviations of lure conditions from the no-lure condition) on T2 identification rates: main analysis followed by separate ANOVAs for the two lure types.

Degrees of freedom are 1,13 throughout. *F* and *p* values are printed in bold when *p* ≤ 0.050. *p*-values were entered when *p* ≤ 0.10.

Color lures had an overall negative effect (constant term of ANOVA differing from zero: *<sup>F</sup>*1,13 = 22.0, *p* < 0.001). As predicted, this effect was larger when lures were in the other stream than when they were in the same stream (Lure Side: *<sup>F</sup>*1,13 = 5.9, *p* = 0.03). Furthermore, the negative effect was largest on *L3*L, i.e., left T2 preceded by left T1 (T1 Side × T2 Side *<sup>F</sup>*1,13 = 5.4, *p* = 0.04; simple effect of T1 Side on left T2 *<sup>F</sup>*1,13 = 5.3, *p* = 0.04; on right T2 *<sup>F</sup>*1,13 = 0.1, n.s.).

Digit lures had an overall zero effect (constant term of ANOVA *<sup>F</sup>*1,13 = 0.2, n.s.). But effects differed between lure sides, *<sup>F</sup>*1,13 = 9.3, *p* = 0.009, and between T1 sides, *<sup>F</sup>*1,13 = 15.9, *p* = 0.002, in both cases being negative when sides (of lures or of T1) were the same as T2 and positive when sides differed from T2. Important were the strong interactions of Lure Side × T2 Side, *<sup>F</sup>*1,13 = 25.4, *p* < 0.001, and of Lure Side × T1 Side, *<sup>F</sup>*1,13 = 8.1, *p* = 0.01. Both interactions reflected that there were large moderating effects (of T2 Side and of T1 Side) on lure effects on T2 identification when lures and T2 were in the same stream (solid grey line in Figure 2; effect of T2 Side *<sup>F</sup>*1,13 = 16.2, *p* = 0.001; of T1 Side *<sup>F</sup>*1,13 = 29.7, *p* < 0.001) in contrast to absence of effects when lures and T2 were in different streams (dashed grey line; effect of T2 Side *<sup>F</sup>*1,13 = 2.0, *p* = 0.19; of T1 Side *<sup>F</sup>*1,13 = 2.0, *p* = 0.18). Thus, when lures and T2 were in the same stream (solid grey line), lure effects were negative both for left T2 (*L3*L and *R3*L) and when T1 was on the same side (*L3*L and R*3R*), and were more positive both for right T2 and when T1 was on the other side. Thereby, when looking at these interactions from the viewpoint of differential effects of lure side, these effects of lure side—negative with same-side lures, positive with other-side lures—were focused on left T2 (effect of Lure Side on left T2 *<sup>F</sup>*1,13 = 43.6, *p* < 0.001; on right T2 *<sup>F</sup>*1,13 = 1.1, n.s.) and on same-side T1 (effect of Lure Side with same-side T1 *<sup>F</sup>*1,13 = 26.5, *p* < 0.001; with other-side T1 *<sup>F</sup>*1,13 = 0.0, n.s.). Whether these effects were indeed significantly different from zero was tested by evaluating the deviations from zero of the constant terms of ANOVAs conducted on single levels of those two two-way interactions Lure Side × T2 Side and Lure Side × T1 Side. Effects were reliably negative when T2 was in the same stream as lures (solid grey line) and either was left (*L3*L and *R3*L), *<sup>F</sup>*1,13 = 16.8, *p* < 0.001, or when T1 was in the T2 stream (*L3*L and *R3*R), *<sup>F</sup>*1,13 = 23.9, *p* < 0.001. Effects were reliably positive when T2 was in the other stream than lures (dashed grey line) and was left (*L3*L and *R3*L), *<sup>F</sup>*1,13 = 5.7, *p* = 0.03, and when lures were in the same stream as T2 (solid grey line) but T1 was in the other stream (*R3*L and *L3*R), *<sup>F</sup>*1,13 = 7.5, *p* = 0.02.

Additionally, the lag 1 data were compared to the other-side-than-T1 data of lag 3, replacing the previous factor T1 Side by Lag (lag 1, lag 3) to have the factors Lure Type, Lure Side, Lag, and T2 Side. No e ffect of Lag came below the *p* = 0.05 threshold (all *<sup>F</sup>*1,13 ≤ 4.5, *p* ≥ 0.054).

#### *3.2. ERP Reflections of Lure Processing*

Lure-evoked ERPs were computed from 150 trials per participant (minus artifact-a ffected epochs).
