Target Fidelity, but not Inducer Fidelity, Modulates Repulsive Serial Dependence of Visual Working Memory Representations

Visual representations are open to systematic functional biases. In visual working memory, representations of serially presented stimuli can either attract or repel each other. Such serial dependence biases are thought to reflect adaptive Bayesian processes yielding optimal perceptual decisions under uncertainty. This perspective suggests that serial dependence should adapt to the degree of uncertainty in both the current target and the inducer (previous target) representations. When the current target representation is noisy, attractive serial dependence increases, but the effect of uncertainty in the inducer is not clear. Furthermore, less is known about the effect of inducer or target uncertainty, especially in tasks where repulsive biases would optimize performance. In an orientation estimation task, we presented three consecutive targets (T1, T2, T3) in rapid succession, with the T1-T2 Lag of 3 or 7; T3 always followed T2 at lag 7. T2 fidelity was lower at Lag 3 due to attentional blink. This design allowed us to test the impact of representational noise on serial dependence effects when T2 is both a target, and an inducer (for T3). We are the first to demonstrate that reduced attentional resources increased the repulsive serial bias in T2; inducer noise in T2 did not modulate the bias in T3. Repulsive biases extended beyond immediate perceptual history, as T3 estimates were repelled by T1 orientation. T2 estimates were also repelled from the subsequent T3 orientation, demonstrating a repulsive effect emerging during working memory maintenance. Our findings show adaptive error reduction in working memory, beyond Bayesian optimality.