# Proximal procrastination of saccades: “paradoxical” delays to larger objects explained by a simple payoff-time heuristic

## TL;DR

The paper explains why eye movements to closer or larger objects are delayed, using a new model based on a trade-off between information gained from quick glances and detailed focus.

## Contribution

The novel contribution is the 'proximal procrastination' rule, which explains saccade latency through a payoff-time heuristic involving information gain trade-offs.

## Key findings

- Relative eccentricity explains 88% of saccade latency variance.
- Proximal procrastination is the largest parametric effect on saccade preparation timing.
- Free choices between proximal and distal targets are dominated by motor priority.

## Abstract

Our most common decision is rife with procrastination: saccade latencies are typically 2-5x minimum sensorimotor pathway delays. Procrastination is explained as time to accumulate sensory evidence for target selection. Larger targets, or those nearer the fovea, have larger cortical representation and salience, and thus should elicit faster targeting. Paradoxically, the opposite is true. We present the largest parametric effect on saccade preparation timing in simple objects (>100 ms). Proximal or larger targets were systematically delayed, with relative eccentricity explaining 88% of latency variance. A payoff-time model pitting information gained from peripheral preview against that from foveation explained both object-sized and foveal microsaccade latency peaks. Free choices between proximal (high salience-by-proximity) and distal (high motor-priority) targets found priority dominating. Collectively, these results unite disparate findings in oculomotor literature around a proximal procrastination rule. The extraordinary structure and strength of the latency data, coupled with naturalistic saccades being object-targeted, imply wide scientific and, potentially, applied importance.

•Object-size sets “motor intensity” parallel to Pieron’s Law for saccade latencies•Largest effect on saccade preparation decision: parametric proximal procrastination•Foveal-Perifoveal Trade-off of information gain predicts latencies•A “free choice” paradigm has choices obligatorily set by proximal procrastination

Object-size sets “motor intensity” parallel to Pieron’s Law for saccade latencies

Largest effect on saccade preparation decision: parametric proximal procrastination

Foveal-Perifoveal Trade-off of information gain predicts latencies

A “free choice” paradigm has choices obligatorily set by proximal procrastination

Cognitive neuroscience; Life Sciences