Used for?

• Lab experiments:

  • Research in labs --> very scientific
  • Reliable with good control of variables
  • Doesn't tell much for real world --> lack ecologically validity
• Field experiments:

  • Natural situation so they have more ecological validity
  • Less control of variables
• Natural experiments

  • Naturally occuring situation
  • Experimenter has little control of variables
  • Ps can't be randomly assigned
  • High ecological validity but lack reliability
• Principles:

  • Mental systems have limited capacity
  • Control mechanism oversees all mental process
  • No two way flow of information
• Developed as computer age developed