# Spatial statistics for gaze patterns in scene viewing: Effects of repeated viewing

## TL;DR

This study applies spatial point process methods, specifically the pair correlation function, to analyze eye movement patterns during scene viewing, revealing increased fixation aggregation upon repeated image viewing and suggesting attentional span as a key factor.

## Contribution

It introduces the use of the pair correlation function to study fixation dependencies and demonstrates how repeated viewing affects fixation aggregation in scene viewing.

## Key findings

- Fixation locations are more aggregated within four degrees than chance.
- Aggregation of fixations increases upon second viewing of the same image.
- A narrower attentional span may explain differences in fixation patterns between viewings.

## Abstract

Scene viewing is used to study attentional selection in complex but still controlled environments. One of the main observations on eye movements during scene viewing is the inhomogeneous distribution of fixation locations: While some parts of an image are fixated by almost all observers and are inspected repeatedly by the same observer, other image parts remain unfixated by observers even after long exploration intervals. Here, we apply spatial point process methods to investigate the relationship between pairs of fixations. More precisely, we use the pair correlation function (PCF), a powerful statistical tool, to evaluate dependencies between fixation locations along individual scanpaths. We demonstrate that aggregation of fixation locations within four degrees is stronger than expected from chance. Furthermore, the PCF reveals stronger aggregation of fixations when the same image is presented a second time. We use simulations of a dynamical model to show that a narrower spatial attentional span may explain differences in pair correlations between the first and the second inspection of the same image.