Behavior-based robotics or behavioural robotics is the branch of robotics that does not use an internal model of the environment. For instance, there is no programming in the robot of what a chair looks like, or what kind of surface the robot is moving on _ all the information is gleaned from the input of the robot's sensors. The robot uses that information to react to the changes in its environment.

Behavior_based robots (BBR) usually show more biological-appearing actions than their computing-intensive counterparts, which are very deliberate in their actions. A BBR often makes mistakes, repeats actions, and appears confused, but can also show the anthropomorphic quality of tenacity. Comparisons between BBRs and insects are frequent because of these actions. BBRs are examples of Weak artificial intelligence

The school of behavior-based robots owes much to work undertaken in the 1980s at the Massachusetts Institute of Technology by Professor Rodney Brooks, who with students and colleagues built a series of wheeled and legged robots utilising the subsumption architecture. Brooks' papers, often written with lighthearted titles such as "Planning is just a way of avoiding figuring out what to do next", the anthropomorphic qualities of his robots, and the relatively low cost of developing such robots, popularised the behavior_based approach.

Brooks' work builds _ whether by accident or not _ on two prior milestones in the behavior_based approach. In the 1950s, Walter Grey Walter, an English scientist with a background in neurological research, built a pair of vacuum tube_based robots in the 1950's, which were exhibited at the Festival of Britain in 1951, and which have simple but effective behavior_based control systems.

The second milestone is Valentino Braitenberg's 1984 book, "Vehicles _ Experiments in Synthetic Psychology" (MIT Press). He describes a series of thought experiments demonstrating how simply wired sensor/motor connections can result in some complex_appearing behaviors such as fear and love.

Some of the latest work in BBR is from the BEAM robotics community, which has built upon the work of Mark Tilden. Tilden was inspired by the reduction in the computational power needed for walking mechanisms from Brooks' experiments (which used one microcontroller for each leg), and further reduced the computational requirements to that of logic chips, transistor_based electronics, and analog circuit design.