Self-Sustaining Iterated Learning

In this form of iterated learning, agents teach each other in sequence: X teaches Y, who then teaches Z, who then teaches... [1-10]. By a classic result of Griffiths and Kalish [3], Quenya will vanish after a finite number of iterations, at which point the agents, assumed to be rational, will be "teaching" each other plain English. In other words, after a while, learners will be taught nothing they don't already know: iterated learning is not self-sustaining. Such findings are hard to validate empirically but variants of it are within the reach of experimental psychology. As early as 1932, in fact, the English psychologist Frederic Bartlett used iterated learning to expose hidden biases among humans. He presented a picture of an owl to a person for given period of time and then asked her to draw it from memory. Her picture was then shown to the next learner for the same amount of time, who then proceeded to draw it back from memory. After 20 iterations of this process, to Bartlett's surprise, what was being drawn was no longer an owl but, quite clearly, a This work was supported in part by NSF grant CCF-1420112.