Attentional Blink
T2. A paired-samples t-test revealed that absolute T2|T1 error was significantly lower in the Lag 7 condition (M = 11.35, SD = 2.23) compared to the Lag 3 condition (M = 13.01, SD = 2.20), t(21) = 4.62, p < .001, Cohen’s d = .75. The Bayesian paired-samples t-test also showed decisive evidence in favor of the alternative hypothesis over the null, with the BF10 of ~194. We observed the typical attentional blink effect for T2 representations.
T3. A paired-samples t-test revealed that absolute T3|T1 error did not differ significantly across the Lag 3 (M = 13.13, SD = 2.09) and the Lag 7 (M = 12.78, SD = 2.77) conditions, t(21) = 1.03, p = .31, Cohen’s d = .14. The Bayesian paired-samples t-test suggested that the data is 2.78 times more likely under the null hypothesis than the alternative. Absolute T3|T1 error was comparable across Lag 3 and Lag 7 conditions, suggesting that error in T3 estimates was not influenced by the T1-T2 Lag manipulation, as expected.
Serial Dependence
T2 – Effect of Target Fidelity. To test whether there is a serial bias in T2 estimates, and if so, whether it differed across Lag conditions, we conducted a paired-samples t-test on α values estimated based on individual data by fitting a first derivative of the Gaussian function (DoG). The results indicated a repulsive serial dependence effect which was greater in the Lag 3 (M = -8.17, SD = 4.53) condition compared to the Lag 7 condition (M = -5.05, SD = 4.52), t(21) = -4.03, p < .001, Cohen’s d = -.69. The Bayesian paired-samples t-test suggested that the data was ~55 times more likely under the alternative model including Lag as a factor compared to the null model.
We also conducted a nonparametric permutation analysis on the aggregated data pooled over participants as there is a limited number of observations per condition per participant. In doing so, we followed the literature (6,11). The observed parameter α values were -7.60 in the Lag 3 condition and -4.92 in the Lag 7 condition, again confirming the repulsive effect. The results suggested that the α difference between Lag 7 and Lag 3 conditions was significant, αLag7-Lag3 = 2.68, 95% CI [-1.15, 1.15], pperm < .001. The fitted curves as well as the observed data can be seen in Figure 2. The results suggested that the magnitude of the repulsive serial dependence bias was greater when the target fidelity was rendered low due to the attentional blink effect compared to when the target fidelity was higher (outside the attentional blink window). Overall, estimates based on both individual and aggregated data suggested that there is an effect of target fidelity on the repulsive bias. We had also observed very similar findings in the pilot experiment (Figure S2).
T3 – Effect of Inducer Fidelity. Next, we tested whether the serial bias in target (T3) estimates was influenced by the fidelity of the inducer (T2). Attentional blink analysis suggested that the inducer, T2, varied in fidelity as a function Lag whereas the target T3 fidelity remained constant across Lag conditions. To determine whether there was any change in the serial bias based on inducer fidelity, we compared bias for T3 across Lag conditions. A paired-samples t-test on individual α values revealed that the repulsive serial bias in T3 estimates did not differ across Lag 3 (M = -8.59, SD = 4.49) and Lag 7 (M = -7.33, SD = 4.25) conditions, t(21) = -1.97, p = .063, Cohen’s d = -.29. Bayes factor analysis showed anecdotal support for the alternative hypothesis compared to the null, with a BF10 of 1.13.
The analysis based on the aggregated data suggested that the α parameter values estimated based on the observed data were -8.22 in the Lag 3 condition and -6.40 in the Lag 7 condition. The results suggested that the difference in the parameter a across the Lag conditions was significant, αLag7-Lag3 = 1.82, 95% CI [-1.26, 1.28], pperm = .005, suggesting that the repulsive bias in the target T3 was stronger when the inducer (T2) had low fidelity due to the attentional blink, compared to when the inducer fidelity was better (outside the attentional blink window). DoG fits and the observed data can be seen in Figure 3. This finding was unexpected as it is on the contrary to the optimal strategy. In detail, as the Bayesian accounts of serial dependence suggest (e.g., 6,16), an ideal observer would put more weight into the current sensory input in case the uncertainty in the prior (inducer) is high. However, what we observed here suggested that the observers relied more on the inducer while responding to the current target when their representation of the inducer orientation was more inaccurate compared to when the inducer representation was less inaccurate. On the other hand, it is important to note that the results of the individual fits suggested no differences in terms of the magnitude of the repulsive bias in T3 estimates across Lag conditions. In addition, as seen in Figure 3, although we applied a correction to eliminate orientation-specific biases, the intercept of T3|T1 estimation error in the Lag 3 condition is off in the repulsion side compared to the Lag 7 condition. This might have influenced the fit and artificially increased the half-amplitude estimate of the DoG function. In a planned exploratory analysis, we aimed to further investigate other possible effects that might have influenced participants’ reports of T2 and T3, possibly leading to this discrepancy.
The current design required participants to hold on to three target representations briefly in working memory until they were prompted to reproduce these targets in the presented order. The typical serial dependence analyses reported above focused only on the effect of the relative orientation of the immediately preceding target on estimation error in a given target representation. While this effectively quantifies the effect of the relative difference between two successive targets in the stream on the subsequent target’s representation, it leaves out the possibility that the other target in the stream might have also influenced the target representation. To account for this, in a planned exploratory analysis, we fitted linear mixed-effects models to our data to predict estimation error while accounting for the effect of the relative difference between the given target and the remaining two targets as well as the effect of Lag, simultaneously. We fitted nested mixed models to predict T2|T1 error and T3|T1 error separately. For the ease of interpretation, we mutated three categorical predictors based on the relative orientation difference between T1 and T2 (T1 vs T2: T1 > T2 and T1 < T2), the relative orientation difference between T3 and T2 (T3 vs T2: T3 > T2 and T3 < T2), and the relative orientation difference between T1 and T3 (T1 vs T3: T1 > T3 and T1 < T3). In these predictors, the target that precedes the “bigger than” sign has a more clockwise orientation than the target that follows it. In this case, negative error indicates repulsive bias. The target that precedes the “smaller than” sign is more counterclockwise than the one following. Figure 4 and Figure 5 present T2|T1 and T3|T1 estimation errors as a function of these predictors based on relative orientation differences.
To predict T2|T1 estimation error, we fitted linear mixed models with Lag, T1 vs T2 , and T3 vs T2 as fixed effect predictors and participant as the only random effect predictor. We followed a stepwise approach. Table 1 shows the nested model structure and model diagnostics. The likelihood ratio tests revealed that the model including T1 vs T2, T3 vs T2, Lag, and the interaction of T1 vs T2 and Lag as fixed predictors was the best fitting model, χ2(1) = 14.49, p < .001. The model's intercept corresponds to the Lag 3 condition where both T1 and T3 were more clockwise than T2 (T1 vs T2: T1 > T2 and T3 vs T2: T3 > T2). Within the best fitting model, Type II Wald Chi-square tests suggested that there was no significant main effect of Lag, χ²(1) = 0.36, p = .55, but there were significant main effects of T1 vs T2, χ²(1) = 418.94, p < .001, and T3 vs T2, χ²(1) = 73.55, p < .001. Moreover, the interaction between Lag and T1 vs T2 was significant, χ²(1) = 14.51, p < .001. The results suggested that T2 estimation error shows repulsion away from both T1 and T3 (Figure 4; explained in detail below). Critically, however, attention manipulation further amplified the repulsion in T2 from the preceding target T1 but not from the succeeding target T3. These findings were consistent with the results based on both individual and aggregate DoG fits.
In Figure 4, overall, the positive slope of the lines indicates the repulsive effect of relative T1 orientation on T2 estimates. The vertical offset of the green line, shifted upward, and the orange line, shifted downward, indicates the repulsive effect of relative T3 orientation on T2 estimates. The steeper slope in the lines in the Lag 3 condition (left panel) compared to Lag 7 (right panel) shows the modulation of the T1-induced bias by Lag. In contrast, the similar vertical separation between the green and orange lines across panels indicates no modulation of the T3-induced bias by Lag.
To further explain this based on Figure 4, let’s focus on the left panel corresponding to the Lag 3 condition. The bottom left point (in orange) is the intersection where both T1 and T3 were more clockwise (+°) compared to T2 (T1 > T2 & T3 > T2). It can be seen that the error is further counterclockwise (–°) in this condition. The exact opposite is on the top right point (in green) in the left pane. When both T1 and T3 are more counterclockwise (–°) than T2 (T1 < T2 & T3 < T2), the error is further clockwise (+°). This suggests that when both T1 and T3 repelled T2 in the same direction the observed repulsion was stronger. The remaining two points show conditions where T1 and T3 repelled T2 in opposite directions. These two points are closer to y = 0, reflecting that when T1 and T3 repelled T2 in opposite directions, the overall bias appears to reduce. The same logic applies to the Lag 7 condition as well.
Table 1 Linear mixed-effects models of T2|T1 estimation error
|
Predictors of T2|T1 Error
|
n parameters
|
ΔAIC
|
ΔBIC
|
χ2
|
|
~ T1vsT2 + (1 | participant)
|
4
|
80.98
|
63.74
|
-
|
|
~ T1vsT2 + T3vsT2 + (1 | participant)
|
5
|
10.85
|
0
|
72.13***
|
|
~ Lag + T1vsT2 + T3vsT2 + (1 | participant)
|
6
|
12.49
|
8.04
|
0.36
|
|
~ Lag x T1vsT2 + T3vsT2 + (1 | participant)
|
7
|
0
|
1.94
|
14.49***
|
|
~ Lag x T1vsT2 x T3vsT2 + (1 | participant)
|
10
|
3.84
|
24.97
|
2.15
|
Note. *** indicates statistical significance at p < .001. Intercept corresponds to the Lag 3 condition where both T1 and T3 were more clockwise than T2 (T1 vs T2: T1 > T2 and T3 vs T2: T3 > T2).
As above, also for T3 we explored whether the relationship between T2 and T3 and T1 and T3 impacted the bias in T3 estimates. We fitted linear mixed models to predict T3|T1 error with Lag, T2 vs T3 , and T1 vs T3 as fixed effect predictors and participant as the only random effect predictor, adopting a stepwise approach. The model including T2 vs T3 and T1 vs T3 as fixed effect terms showed better fit to the data compared to the simpler model with T2 vs T3 as the sole fixed term, χ2(1) = 79.20, p < .001. As seen in Table 2, adding additional predictors did not significantly improve the model fit, all ps > .05, suggesting that T2 vs T3 and T1 vs T3 captured the critical variance in T3|T1 estimation error. Within the best fitting model, both T2 vs T3, χ2(1) = 149.37, p < .001, and T1 vs T3, χ2(1) = 100.27, p < .001, were significant predictors. This suggested that T3 estimates were not only influenced by the relative orientation between T2 and T3, but they were also repelled away from T1 presented earlier in the stream (Figure 5). However, in line with the results of the analysis based on individual DoG fits, neither the effect of T2 vs T3 nor the effect of T1 vs T3 varied across Lag conditions. In Figure 5, the positive slope of the lines demonstrates the repulsive effect of relative T2 orientation on T3 estimates. The vertical offset of the yellow line, shifted upward, indicates that T3 estimates are more clockwise when T1 is more counterclockwise relative to T3. Conversely, the purple line, shifted downward, indicates the repulsive effect of relative T1 orientation on T3 estimates shift errors toward more counterclockwise direction when T1 is more clockwise relative to T3. Therefore, it is apparent that the T1-induced and T2-induced effects on T3 estimates are additive.
To summarize, the planned exploratory analysis revealed that both T2 and T3 representations repelled away not only from the immediately preceding target (T1 and T2, respectively) in the stream but also from the other target (T3 and T1, respectively) in the stream3. Critically, in T2 representations, when attention allocation to T2 was restricted, repulsion from the preceding target T1 was greater. This was consistent with the findings of the DoG-based analyses. However, the repulsion from T3 did not vary depending on the attention allocation to T2 and was an additive effect (Figure 4). Similarly, repulsive effects in T3 estimates away from T1 and T2 did not vary significantly depending on the attention allocation to the inducer T2 (Figure 5). This was also in line with the results of the analysis based on individual DoG fits but not the one based on aggregate DoG fits.
Table 2 Linear mixed-effects models of T3|T1 estimation error
|
Predictors of T3|T1 Error
|
n parameters
|
ΔAIC
|
ΔBIC
|
χ2
|
|
~ T2vsT3 + (1 | participant)
|
4
|
97.13
|
90.74
|
-
|
|
~ T2vsT3 + T1vsT3 + (1 | participant)
|
5
|
0
|
0
|
99.13***
|
|
~ Lag + T2vsT3 + T1vsT3 + (1 | participant)
|
6
|
1.75
|
8.15
|
0.25
|
|
~ Lag x T2vsT3 + T1vsT3 + (1 | participant)
|
7
|
0.66
|
13.46
|
3.09
|
|
~ Lag x T2vsT3 x T1vsT3 + (1 | participant)
|
10
|
5.53
|
37.52
|
1.14
|
Note. *** indicates statistical significance at p < .001. Intercept corresponds to the Lag 3 condition where both T1 and T2 were more clockwise than T3 (T1 vs T3: T1 > T3 and T2 vs T3: T2 > T3).