Day 21 of 150 Language Difficulty 6/10

Vision fuses with audio to create the McGurk illusion

Quick answer

Vision fuses with audio to create the McGurk illusion. Today's question (McGurk effect) asks about a finding from McGurk, H., & MacDonald, J. in 1976. The correct option is "da-da" — a fused percept matching neither input — full explanation, primary source, and glossary cross-links below.

Today's question

When you watch a video where the lips silently mouth "ga-ga" while the audio plays "ba-ba," most viewers hear:

  1. A "ba-ba" (audio wins)
  2. B "ga-ga" (video wins)
  3. C "da-da" — a fused percept matching neither input
  4. D Both sounds alternating
Reveal the answer and explanation

Correct: C — "da-da" — a fused percept matching neither input

McGurk & MacDonald (1976) discovered that speech perception is multimodal: visual lip information fuses with the audio signal to produce a perceived sound that matches neither input alone. The illusion persists even when the listener knows it is happening — strong evidence that perception is inferential and constructive, not a faithful readout of stimulus energy. The effect underwrites lip-reading and modern audiovisual speech-recognition models.

About the source

McGurk, H., & MacDonald, J. (1976). Hearing lips and seeing voices. Nature, 264(5588), 746–748.

Every Cognition Bible question cites a primary source — a paper, book chapter, or monograph that exists, that we can point to on Google Scholar, and whose finding the question accurately summarizes. No fabricated authority strings, no name-drops without paper-level grounding.

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