Figure 1. Conceptual architecture of operant feedback loops.

Given the operant nature of the learning procedure, vocal learning in songbirds and humans share some conceptual aspects with operant self-learning in Drosophila at the torque meter. The motor system (the vocal system in songbirds and humans, the flight system in flies) generates behavioral actions (vocalizations or torque) which lead to sensory feedback (phonemes, song or heat). This actual outcome is then evaluated with respect to the preferred outcome (intended phoneme, tutor song template or preferred temperature). Any deviation from the preferred outcome will lead to a teaching signal instructing the motor system to modify the generated behavior until the desired state of the animal is reached. This schematic was modified from [30] and inspired by [27], [31], [100].