Skinner’s Project Pigeon

During World War II, The behaviorist B.F. Skinner embarked on what he later called a “crackpot idea, born on the wrong side of the fence intellectually, but eventually vindicated in a sort of middle-class respectability.” His plan was to use trained pigeons to guide armed missiles toward their targets. Some may have had some issues with the ethics involved in putting innocent animals at the center of certain death, but he justified it, viewing their sacrifice as small relative to the devastation Hitler’s relentless bombing was causing in Europe. Radar had not yet been invented, and the complex servo-mechanical equipment of the day required to guide a missile would have left little room for explosives.  Skinner began the training process by the showing the pigeon a dot projected on a translucent screen and, using the technique called shaping, would reward the bird with food when it pecked on the dot. (Shaping, or successive approximation, is a process Skinner developed to encourage specific behaviors he wanted by rewarding small steps toward that action.

In the beginning, any motion a pigeon made toward the screen would be rewarded; as it consistently acted in the general direction of the desired behavior, the criteria would grow more and more specific until the bird was doing exactly what Skinner wanted. He later moved the dot back and forth and the pigeon would follow quickly and precisely track the dot, ultimately training it to track a battleship. In essence, Skinner was using the bird as an animal computer, performing a complicated tracking operation that the technology of the day could only crudely perform but which, over the course of millions of years, evolution had equipped animals to do perfectly. There is a wonderful short video of this on YouTube (

The U.S. Navy gave Skinner a small grant to pursue the project where he constructed a set of optical lenses at the tip of the missile’s nose cone, which focused the missile’s forward view onto a screen placed in front of each of the three pigeons strapped inside. A pneumatic mechanism then steered the missile toward its target based on a mechanical “vote” of two out of three birds agreeing on the direction. Project Pigeon worked beautifully in a number of tests for the Navy, but it was abandoned partly in favor of more promising research efforts, such as the Manhattan Project, and because the idea of pigeons guiding a bomb was a difficult sell to the academic review panels and the military brass.

While attending a father’s day back-to-school event at his youngest daughter Debbie’s school in 1953, he watched with the other fathers from the back of the class as her teacher taught fourth-grade arithmetic. After writing the problem on the blackboard, the teacher would walk up and down the aisle, occasionally pointing out the children’s mistakes. Some students finished quickly and sat bored while others continued to work the problems. The papers were collected, graded by the teacher, and returned to the students the following day.

This immediately gave Skinner insight into some problems in the pedagogy, as well as an idea toward their solution. The lockstep pacing forced students to progress together regardless of their individual abilities and without immediate feedback to their actions. Skinner knew that a corrected paper seen 24 hours later could not serve as a reinforcer and did not present a good scenario for learning. Understanding the value of using mechanical devices in his work with pigeons, he created a crude prototype over the next few days, using a series of cards containing questions, within a box with sliders to “dial in” the answers  It was his first teaching machine.

Believing that learning occurs when desired behaviors are systematically reinforced, Skinner theorized that learning could be accomplished by programming, where the student is led in a directed manner through the content by taking many small steps, each step requiring a response. The student receives immediate feedback for that response and moves forward to the next step only if his answer is correct. In this way, the student controls the pace of learning and only moves forward when the content is fully mastered.

Skinner proposed that programming would take the role of the teacher by designing a series of questions in the manner a teacher might teach, through a series of small approximations toward the goal, not unlike his training of the pigeons in his World War II missiles. Each frame built on what the student already knew and expanded on that knowledge toward the next frame. While the steps are small, a skillful programmer could create a gradual progression where the steps were chained together to create more complex understandings over time.

Excerpted From Teaching Machines: Learning from the Intersection of Education and Technology by Bill Ferster, 2014, Johns Hopkins University Press

About Bill Ferster

Bill Ferster is a research professor at the University of Virginia and a technology consultant for organizations using web-applications for ed-tech, data visualization, and digital media. He is the author of Sage on the Screen (2016, Johns Hopkins), Teaching Machines (2014, Johns Hopkins), and Interactive Visualization (2012, MIT Press), and has founded a number of high-technology startups in past lives. For more information, see