The Interplay of Attention and Memory in Visual Enumeration

Humans navigate and understand complex visual environments by subconsciously quantifying what they see, a process known as visual enumeration. However, traditional studies using flat screens fail to capture the cognitive dynamics of this process over the large visual fields of real-world scenes. To address this gap, we developed an immersive virtual reality system with integrated eye-tracking to investigate the interplay between attention and memory during complex enumeration. We conducted a two-phase experiment where participants enumerated scenes of either simple abstract shapes or complex real-world objects, systematically varying the task intent (e.g., selective vs. exhaustive counting) and the spatial layout of items. Our results reveal that task intent is the dominant factor driving performance, with selective counting imposing a significant cognitive cost that was dramatically amplified by stimulus complexity. The semantic processing required for real-world objects reduced accuracy and suppressed memory recall, while the influence of spatial layout was secondary and statistically non-significant when a higher-order cognitive task intent was driving the human behaviour. We conclude that real-world enumeration is fundamentally constrained by the cognitive load of semantic processing, not just the mechanics of visual search. Our findings demonstrate that under high cognitive demand, the effort to understand what we are seeing directly limits our capacity to remember it.