Repulsive serial dependence in visual working memory modulated by target fidelity

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 (~ 83 ms each), with the T1-T2 Lag of 3 or 7; T3 always followed T2 at Lag 7. T2 fidelity (operationalized as absolute error and precision in estimates) 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. We report repulsive biases that extend beyond immediate perceptual history. 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 uncertainty minimization in working memory, beyond popular Bayesian accounts of serial dependence.