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PSYC1102: Koko the Sign Language Gorilla

Sep 9, 2025

Overview

This lecture tells the story of Koko, a gorilla who learned sign language, formed deep relationships, displayed intelligence and emotion, and changed perceptions about animal consciousness.

Early Life and Background

  • Koko, born July 4, 1971, at San Francisco Zoo, was named Hanabi-Ko ("fireworks child").
  • She was rejected by her mother after illness, leading to early separation and isolation.
  • Francine "Penny" Patterson, a Stanford student, began to work with Koko in 1972 for PhD research.

Learning Sign Language and Intelligence

  • Koko was taught sign language despite initial challenges, as she would not let anyone guide her hands.
  • By age three, Koko knew about 200 signs and could express emotions.
  • She demonstrated humor and creativity, inventing new signs like "finger bracelet" for ring and "eye hat" for mask.
  • Koko’s intelligence was measured at an IQ of 70–90, comparable to a young child.
  • She could draw and communicate complex ideas using sign language.

Social Interactions and Emotional Depth

  • Koko formed friendships with fellow gorillas Michael and Ndume, both of whom learned sign language.
  • She used sign language to express feelings, make jokes, and describe relationships.
  • Koko had a remarkable friendship with cats, treating them gently and expressing deep grief when one died.
  • She showed self-awareness by passing the mirror recognition test at age 19.

Daily Life and Interests

  • Koko enjoyed watching movies; her favorites included "Tea with Mussolini" and "Jurassic Park."
  • She learned to use a computer to type words and played musical instruments like harmonica and recorders.
  • Koko’s photo with her kitten appeared on the cover of National Geographic.

Public Impact and Legacy

  • Koko met celebrities such as Robin Williams, forming emotional connections with them.
  • Her behavior and abilities challenged scientific views of animal intelligence and emotion.
  • Koko became a symbol for conservation and interspecies understanding, often advocating for care of nature.

Concepts of Death and Final Message

  • When shown a skeleton, Koko signed "dead" and described the afterlife as a "comfortable hole."
  • Before her death, Koko urged humans to care for the Earth: "Fix Earth! Help Earth! Nature see you."

Key Terms & Definitions

  • Sign Language — A system of hand gestures used for communication, taught to Koko for human-ape interaction.
  • Theory of Mind — The ability to understand others have their own thoughts and feelings.
  • IQ (Intelligence Quotient) — A score derived from standardized tests to measure intelligence.
  • Mirror Self-Recognition Test — A test for self-awareness; passing it shows one recognizes themselves in a mirror.

Action Items / Next Steps

  • Review Koko’s story for examples of animal intelligence on upcoming tests.
  • Reflect on the implications of Koko’s legacy for discussions on animal rights and conservation.