The theoretical backdrop for the work is the increasingly popular Bayesian account of serial dependence. According to this framework, the brain behaves like an intuitive statistician, combining noisy sensory evidence with expectations derived from recent experience to produce decisions that are optimal under uncertainty. When the current stimulus is encoded poorly, its internal representation is noisy, and the perceptual system should lean more heavily on the previous stimulus, producing stronger attractive biases. Conversely, when the previous stimulus, often called the inducer, is itself noisy, its influence on the current decision should weaken because a unreliable source of prior information deserves less weight. This elegant logic has generated a large body of findings, mostly documenting attractive biases in tasks such as orientation and face estimation. Yet the framework makes a prediction that has been far less explored: in some tasks, the strategy that actually minimizes error is not attraction but repulsion, and uncertainty should then modulate repulsive biases in predictable ways.

Yildirim and Boduroglu designed an experiment precisely to test that prediction. Participants viewed three tilted gratings in rapid succession, each flashed for roughly 83 milliseconds, and later reported the orientation of each one from memory. The critical manipulation lay in the timing. The first two targets, T1 and T2, were separated by either three or seven intervening stimuli, while the third target, T3, always followed T2 at a lag of seven. At the shorter lag, T2 fell inside the temporal window of the well-known attentional blink, the brief period after detecting one target during which attentional resources for the next are depleted. As a result, participants’ representations of T2 were measurably worse at Lag 3 than at Lag 7, as indexed by larger absolute estimation errors and lower precision. This created a natural experiment in representational noise: the same stimulus, T2, sometimes served as a well-encoded target and sometimes as a degraded one, and in both cases it also acted as the inducer for the subsequent report of T3.

The results overturned a straightforward reading of the Bayesian account. When T2’s representation was noisier, produced by the attentional blink at the short lag, the repulsive serial bias away from T1 actually grew stronger, not weaker. Reduced attentional resources amplified the tendency for participants’ estimates of T2 to be pushed away from the orientation they had just seen on T1. This is the first demonstration, the authors report, that diminished attention increases repulsive serial bias in working memory. In other words, when the current representation is unreliable, the system does not simply lean harder on the past; instead, in this task regime, it actively differentiates the present from the past, as if exaggerating the contrast between the two to keep them from being confused.

Equally striking was what did not change. The noisiness of the inducer, that is, the fidelity of T2, had no measurable effect on the bias observed in estimates of T3. Whether T2 had been encoded under the attentional blink or with full attentional resources, the repulsive pull of T2 on T3 estimates remained statistically indistinguishable. Under a strict Bayesian reading, a degraded inducer should contribute a weaker prior and therefore a smaller bias. The absence of such modulation suggests that the brain may treat the stored memory trace of a stimulus as a fixed reference point for differentiation, regardless of how faithfully that stimulus was originally captured, or that the adaptive mechanism at work here is not the classic Bayesian weighting scheme at all.

Perhaps the most intriguing findings concern the temporal reach of the repulsive effect. Serial dependence is usually studied between adjacent items, and many researchers have assumed that its influence decays rapidly with intervening stimuli. But in this experiment, estimates of T3 were repelled not only by T2 but also by T1, an item separated from T3 by a lag of ten stimuli in the rapid stream. The bias therefore extended well beyond the immediate perceptual history, implying that multiple past representations can coexist in working memory and each exert a distinct repulsive influence on a current report. This long-range repulsion is difficult to reconcile with simple low-level adaptation accounts, in which sensory neurons tuned to the previous orientation become fatigued and shift subsequent percepts away, because such aftereffects are typically short-lived and confined to the immediately preceding stimulus.

The study also uncovered evidence of repulsion operating in the opposite direction of time. Estimates of T2 were pushed away from the orientation of T3, the stimulus that followed it. Since T3 had not yet been presented when T2 appeared, this backward bias could not reflect perception at encoding. Instead, the authors argue, it emerged during the maintenance period, while T2’s representation was being held in working memory and before T3’s report was required. This implies that repulsive differentiation is an active, ongoing computation performed on stored representations rather than a passive residue of earlier sensory processing. When a new item enters working memory, existing representations appear to be reorganized to maximize their separation from the newcomer, a form of online uncertainty minimization that unfolds during the retention interval itself.

Taken together, these findings complicate the popular narrative that serial dependence is a single, attractively inclined mechanism serving perceptual stability. The authors conclude that the pattern they observed reflects adaptive uncertainty minimization in working memory that goes beyond standard Bayesian accounts of serial dependence. When a target representation is noisy, the optimal strategy for distinguishing successive items in this task is to push them apart, and the visual system appears to implement exactly that strategy, amplifying repulsion under attentional deprivation. At the same time, the insensitivity of downstream biases to inducer fidelity, the long-range influence of T1 on T3, and the backward repulsion from T3 onto T2 collectively suggest that the underlying mechanism is more like an active separation process operating across the entire contents of working memory than a passive weighting of previous percepts as priors.

The work, which was supported by the Scientific and Technological Research Council of Turkey through a 1001 program grant and doctoral and international fellowships to the first author, carries implications well beyond the laboratory. Visual working memory underlies everyday activities as varied as navigating a crowded street, comparing two paint swatches, or tracking a moving vehicle through traffic, and all of these depend on keeping successive percepts distinct. The discovery that attentional lapses strengthen the active separation of memories offers a new lens on the errors people make under cognitive load, and it may inform models of perceptual decision making, visual search, and even clinical conditions characterized by attentional dysfunction. For now, the study stands as a vivid reminder that memory is not a passive recording but a dynamic negotiation between past and present, one in which the brain sometimes decides that the best way to remember what it just saw is to remember it as deliberately different from what came before.

Subject of Research: Repulsive serial dependence in visual working memory and how target fidelity shapes serial biases

Article Title: Repulsive serial dependence in visual working memory modulated by target fidelity

Article References: Yildirim, B., & Boduroglu, A. (2026). Repulsive serial dependence in visual working memory modulated by target fidelity. BMC Biology. https://doi.org/10.1186/s12915-026-02739-9

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02739-9

Keywords: visual working memory, serial dependence, serial bias, attentional blink, orientation estimation, Bayesian inference, perceptual decision making, attention, visual adaptation, working memory maintenance, repulsive bias, target fidelity