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Related Experiment Video

Updated: Jun 21, 2026

Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior

Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior

Published on: April 16, 2014

A historical note on illusory contours in shadow writing.

Stefano Vezzani¹, Barbara F M Marino

¹Department of Neuroscience, Section of Physiology, University of Parma, 39 via Volturno, 43100 Parma, Italy.

|August 11, 2009

Summary

Illusory contours were first described by Jastrow in 1899 using shadow words, predating Schumann's widely accepted 1900 publication. This research traces shadow writing's history in psychology.

Area of Science:

Psychology
Visual Perception
History of Science

Background:

The creation and study of illusory contours are often attributed to Schumann (1900).
Psychological literature has a history of exploring visual phenomena and perception.

Observation:

Jastrow (1899) previously produced illusory contours using a shadow word technique.
This observation challenges the established timeline for the discussion of illusory contours.

Findings:

This study reveals that Jastrow's 1899 work predates Schumann's 1900 publication on illusory contours.
A historical review of shadow writing in psychological literature is presented, examining key figures.

Implications:

Revises the historical understanding of illusory contour research.

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Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior

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Highlights the importance of examining earlier literature for foundational discoveries in visual perception.