Why the Other Line Always Moves Faster: Confirmation Bias in Queue Perception

This paper investigates the pervasive subjective experience that adjacent queues move faster than one's own, a phenomenon we term "queue velocity illusion" (QVI). Through a series of controlled experiments in simulated and real retail environments (total n=1,450), we demonstrate that subjects consistently overestimate the relative speed of adjacent queues by a factor of 2.3 (95% CI: 2.1-2.5), even when objective measurements confirm equal or slower progression.

Our theoretical framework attributes QVI to an asymmetry in attentional allocation: subjects attend to adjacent queue movement during their own periods of stasis (when their queue is not moving) but fail to monitor adjacent queues during periods of self-movement. This creates a sampling bias wherein adjacent queue progress is disproportionately represented in memory.

Experiment 2 tracked eye movements during queuing, confirming that subjects directed 73% more visual attention to adjacent queues during stationary periods. Experiment 3 introduced a "queue commitment" intervention wherein subjects were asked to predict, before joining, which queue would complete first. Remarkably, even subjects who correctly predicted their queue would be faster subsequently reported feeling that adjacent queues had moved faster.

We propose that QVI represents a fundamental limitation in human temporal and spatial comparison processing, likely exacerbated by loss aversion (the psychological cost of "losing" to an adjacent queue exceeds the benefit of "winning"). Practical interventions tested include single-queue systems (which eliminate comparison opportunities) and digital queue position displays (which provide objective feedback). Both interventions significantly reduced self-reported queue anxiety (Cohen's d = 0.8 and 0.6, respectively).