4. Texts

4.1. Braitenberg, Valentino. 1984. Vehicles: Experiments in Synthetic Psychology. Cambridge, MA: MIT Press.

John Wiseman:

"In the book : Experiments in Synthetic Psychology, Valentino Braitenberg describes a series of thought experiments in which ``vehicles'' with simple internal structure behave in unexpectedly complex ways. He describes simple control mechanisms that generate behaviors that, if we did not already know the principles behind the vehicles' operation, we might call aggression, love, foresight and even optimism. Braitenberg gives this as evidence for the ``law of uphill analysis and downhill invention,'' meaning that it is much more difficult to try to guess internal structure just from the observation of behavior than it is to create the structure that gives the behavior."

Michael Dawson:

Braitenberg begins with his simplest vehicle, one in which a single sensor is attached to a single motor. His innovation with this vehicle: the propulsion of the motor is directly proportional to the signal being detected by the sensor; so, the stronger the sensed signal, the faster the motor. "Here we have introduced a bit of Aristotelian physics. Aristotle, like everybody else between this ancient Greek philosopher and the less ancient Italian physicist Galileo, thought that the speed of a moving body is proportionate to the force that drives it."

In a frictionless world, the behavior of this vehicle should be straightforward. For example, imagine that the vehicle moves through a pool of water, and that the sensor detects temperature. The vehicle will always move in a straight line, slowing down in the cold, speeding up in the warm.

Complications in the behavior of the vehicle arise by making the environment more complex. For instance, add the effect of friction. Now, the vehicle can come to a full stop when the temperature that it senses drives the motor so slowly that the force of friction cannot be overcome. Friction will also cause random deviations in trajectory, producing something like Brownian motion + thrust.

"Imagine, now, what you would think if you saw such a vehicle swimming around in a pond. It is restless, you would say, and does not like warm water. But it is quite stupid, since it is not able to turn back to the nice cold sport it overshot in its restless ness. Anyway, you would say, it is ALIVE, since you have never seen a particle of dead matter move around quite like that."

The preceding paragraph provides one of Braitenberg's basic themes: the inferred properties of the system (based on the basis of behavioral observations) are more complicated from the known structure of the artifact from the designer's perspective.

Some questions to keep in mind now that this theme has been presented: How does this reflect upon cognitive psychology, or indeed on any school of psychology in general? Is the methodology of psychology necessarily going to provide theories that are more complex than required?

[Chapter 2] describes three different vehicles, all of which can be thought of as more complex versions of vehicle 1. These new vehicles reflect two new innovations: (1) they all have more than one sensor/motor system (to be precise, two motors and two sensors each), and (2)the pattern of connectivity from sensors to motors is manipulated. There is still a directly proportionate relationship between the strength of the signal detected by the sensor and the speed generated by the motor to which the sensor is connected.

Vehicle 2a has the left sensor connected to the left motor, and the right sensor connected to the right motor. The behavior of this vehicle is quite interesting. If the sensor source is directly ahead, it will speed up and charge the source, running into it if the vehicle's path is not deflected. However, if the source is off to one side, this vehicle will turn away from the source. Braitenberg describes it as a COWARD.

Vehicle 2b has crossed connections -- (NB: why might this innovation be important to psychologists!!) -- in which the left sensor is connected to the right motor, and the right sensor is connected to the left motor. When the detected quality is dead ahead, this vehicle is like the previous one, and moves straight into it. However, when the signal source is to the side, this vehicle will turn towards it. Indeed, given enough time, the vehicle is guaranteed to hit the source of the signal, provided that it stays in the vicinity of the source. Braitenberg labels it as AGGRESSIVE.

Vehicle 2c has both sensors connected to each motor. Depending on how this connections are made, how might it behave?

Again, think about these little thought experiments in regards to descriptive complexity for the designer vs. descriptive complexity for the observer. Does it make sense to say that we get a lot of complex behavior "for free" given the simple manner in which these machines are built?

4.2. Resnick, Mitchel. 1994. Turtles, Termites, and Traffic Jams: Explorations in Massively Parallel Microworlds. Cambridge, MA: MIT Press.

Booknews, Inc. , 01/01/95 Resnick (media laboratory, Massachusetts Institute of Technology) explores the counterintuitive world of decentralized systems and self- organizing phenomena. Drawing on ideas from computer science, education, psychology, and systems theory, he examines why many people resist decentralized ideas, and describes an innovative computer language, StarLogo, that he designed to help students from grade school and up simulate self-organizing behavior in systems. Resnick analyzes the educational ideas, such as constructionism, and computational ideas, including massive parallelism, underlying StarLogo. Annotation copyright Book News, Inc. Portland, Or.

4.3. Clark, Andy. 1996. Being There : Putting Brain, Body, and World Together Again. Cambridge, MA: MIT Press.

Card catalog description: The old opposition of matter versus mind stubbornly persists in the way we study mind and brain. In treating cognition as problem solving, Andy Clark suggests, we may often abstract too far from the very body and world in which our brains evolved to guide us. Whereas the mental has been treated as a realm that is distinct from the body and the world, Clark forcefully attests that a key to understanding brains is to see them as controllers of embodied activity. From this paradigm shift he advances the construction of a cognitive science of the embodied mind.

4.4. Lloyd, Dan. 1989. Simple Minds. Cambridge, MA: MIT Press.

This book, especially early parts, draws heavily on Braitenberg's Vehicles.

Booknews, Inc. , 11/01/89 Lloyd (philosophy, Trinity College, Hartford) draws on philosophy, neuroscience, and artificial intelligence to speculate how the mind is constructed from the physical matter of the brain. Focuses on the concept of representation. Annotation copyright Book News, Inc. Portland, Or.



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