Fitts' Law for speed-accuracy trade-off describes a diversity-enabled sweet spot in sensorimotor control

TL;DR

This paper introduces a theory linking hardware constraints and system control to explain Fitts' Law, highlighting how diversity in hardware components enables fast and accurate sensorimotor performance despite inherent tradeoffs.

Contribution

It presents a novel theory connecting hardware-level speed-accuracy tradeoffs with system control, explaining the ubiquity of diversity-enabled sweet spots in biological and engineered systems.

Findings

Diversity in hardware components exploits tradeoffs to improve performance.

Biological and technological systems utilize heterogeneity for speed and accuracy.

The theory explains the widespread existence of diverse components in sensorimotor control.

Abstract

Human sensorimotor control exhibits remarkable speed and accuracy, and the tradeoff between them is encapsulated in Fitts' Law for reaching and pointing. While Fitts related this to Shannon's channel capacity theorem, despite widespread study of Fitts' Law, a theory that connects implementation of sensorimotor control at the system and hardware level has not emerged. Here we describe a theory that connects hardware (neurons and muscles with inherent severe speed-accuracy tradeoffs) with system level control to explain Fitts' Law for reaching and related laws. The results supporting the theory show that diversity between hardware components is exploited to achieve both fast and accurate control performance despite slow or inaccurate hardware. Such "diversity-enabled sweet spots" (DESSs) are ubiquitous in biology and technology, and explain why large heterogeneities exist in biological and technical components and how both engineers and natural selection routinely evolve fast and accurate systems using imperfect hardware.