Unit 1: Summary

What Cognitive Scientists Do

• Pick a cognitive (rather than a physical, biological, or social) phenomenon.
• Study the phenomenon until you can describe it relatively precisely.
• Attempt to model the phenomenon.
  • Show how the different variables are related mathematically.
  • Come up with an algorithm, a sequence of steps which specifies how an input to the system yields an output.
  • If necessary, implement the model in the form of a computer program and run it with different inputs and different parameter settings to see if it works and to tune it.
• Publish your results and hope that other cognitive scientists will take you seriously.

Periodicity

• Periodic processes repeat themselves. They have
  • Characterizing variable(s): the thing(s) that actually repeat(s)
  • Period (frequency)
  • Phase angle (at any given time)
• Two or more more periodic processes may be
  • In phase or out of phase
  • Phase-locked or not
• Periodicity and synchronization occur in biological systems because
  • biological systems are physical systems, for which periodicity is one kind of stability
  • it provides a kind of memory for the recurring need for some behavior
  • it allows animals to synchronize their behavior with periodic events in the environment
  • it allows animals to synchronize their behavior with each other
  • it permits

Oscillators and Coupling

• Oscillators: abstract things which exhibit periodicity
• Coupling: influence of one oscillator on another's periodic behavior
  • An oscillator may influence the phase or the period (frequency) of another oscillator.
  • The amount of influence of one oscillator on another depends on some function of the difference in the phase angles of the oscillators.
  • With the right parameter settings, coupled oscillator exhibit synchronization (and sometimes anti-synchronization).
  • Systems of coupled oscillators represent computational models of some biological and cognitive processes, for example, synchronization of firefly flashing, animal gaits, and the perception of musical meter.

Take me back to the Rhythm and Cognition Home Page.

Last updated: 3 October 1995
URL: http://www.indiana.edu/~gasser/summary1.html
Comments: gasser@salsa.indiana.edu
Copyright 1995, The Trustees of Indiana University