PREDOMINANTLY NEUROPHYSIOLOGICAL THEORIES

Modified: 2025-08-09 4:00 PM CDST

What is the relationship between the behavior of learning and its underlying physiological mechanisms. Very early on (1940s) Donald O. Hebb began to propose possible physiological mechanisms for learning. More recently, Eric Kandel and his associates worked out how learning took place in Aplysia, a marine snail. In 2024 he won the Nobel Prize for Physiology and Medicine for that work.

Chapter 14 Donald Olding Hebb

• Major Theoretical Concepts
• Switchboard model of brain altered by Lashley
• Restricted Environments
• Enriched Environments
• Facilitate learning
• Cell Assemblies
  • Are dynamic systems
• Phase Sequences
  • Hebb's rule: two cells active simultaneously will strengthen their connection
    • Babies can combine phase sequences that follow each other: footsteps, faces, being picked up
• Arousal Theory: Hebb on Reinforcement
• Long-Term and Short-Term Memory
  • Short-term memories converted to long-term via consolidation
• Consolidation in the Brain
• Hebb's Influence on Neuroscientific Research
  • Amnesia
  • Retrograde
    • Memories closest to the traumatic event are the least likely to return
  • Reinforcement and the Brain
  • Making Connections: Real Cells and Real Cell Assemblies
  • Learning in Aplysia
    • Kandel among the first to demonstrate Hebb's notions
  • Physiological
    • Hippocampal cells seem to map spaces
    • Up to 95% of synapses occur along dendrites
    • Hebb believed in optimal levels of arousal
    • ECS affects memories more when they are close in time to the ECS administration
    • Riesen's chimpanzees eventually could see normally after being kept in darkness
    • Henry Molaison had surgery for epilepsy, damage to the hippocampus from that surgery, and had anterograde amnesia
    • Parkinson's patients are not aware of their failure to complete puzzle tasks
    • Olds and Milner discovered the reinforcement centers in the brain almost by accident
    • Neuroplasticity can happen after brain injury
    • Excess dendrite development is no always a good thing
    • Neurogenesis can occur into adulthood
  • Long-Term Potentiation
    • Alcohol does not promote long-term potentiation
  • Long-Term Depression
• New Connectionism
  • Artificial Cells and Artificial Cell Assemblies
  • NETtalk program learned to read words not in its original training set
  • Hebb's ideas are now big in computer simulations
• Hebb on Education
  • Teachers should create varied and enriched environments for their students
  • Adult learning is characterized by insight and creativity
• Evaluation of Hebb's Theory
  • Contributions
    • Hebb found that cognitive processes could be studied at the neural level, that repetition and contiguity were the only things necessary, and that reinforcement was not necessary
    • Hebb maintained that childhood experiences were important to intelligence
  • Criticisms
    • Hebb concentrated on physiological excitation but not on physiological inhibition

Back to Learning Theory Main Page

Back to TAMUT PSY 516 page