Felipe Luzardo¹, Yaffa Yeshurun¹; ¹University of Haifa

The ability to prioritize certain regions in our surroundings, known as spatial attention, is critical for human cognition and has been the subject of extensive research. However, studies rarely employ large population samples, resulting in limited exploration of inter-individual variability. Particularly, the question of whether individual differences in spatial attention are qualitative or quantitative remains unaddressed. Quantitative individual differences refer to variability only in the magnitude of attentional effects, while qualitative individual differences imply fundamentally distinct patterns of attention allocation, across individuals. Exploring this distinction is crucial because qualitative differences may reveal diverse underlying mechanisms beyond simple variations in magnitude. We recruited a sizable participant pool (N=514) across three experiments. We used an acuity task paired with valid, invalid, and neutral pre-cues of different types. The inclusion of a neutral cue allowed us to analyze both the averaged attentional benefits—enhanced performance when focusing on the correct location—and costs—diminished performance when attention is directed to the wrong location—and their variability across individuals. The results revealed robust attentional benefits, but not attentional costs, suggesting that facilitatory and inhibitory mechanisms may operate independently. Importantly, comparisons between different neutral cue types revealed no significant differences in performance, indicating that the neutral cue’s characteristics are not critical. Hierarchical Bayesian analyses uncovered true qualitative individual differences; while most participants demonstrated effects in the anticipated direction, some exhibited true effects in the opposite direction. This surprising finding highlights the intricacy of attentional allocation, indicating that a thorough understanding of spatial attention must account for multiple underlying mechanisms that may result in attentional effects in the opposite direction, such as individual differences in levels of internal noise or inhibition of return. These results also emphasize the contribution of large sample sizes to uncover and better understand the full spectrum of cognitive profiles among individuals.