Cognitive Systems: Learning, Memory, & Representation

Cognitive Systems: Lecture 1 // Learning, Memory, & Representation

Perception and Action

  • Perception: Transforms environmental stimuli into internal representations.
  • Action: Converts desires into physical changes in the environment.
    • Key components in animals: action occurs in the brain and through sensory organs (actuators).
    • In robotics: perception utilizes sensors; action employs actuators (example: light laser sensors).

Types of Cognitive Systems

  1. Disembodied Software:
    • Involves collaborative networking and the use of arithmetic to create preferences through software.
    • Example: Artificial intelligence applications.
  2. Distributive Cognition:
    • Suggests that cognition is not limited to a single brain and can involve multiple systems and individuals.
    • Example: Amazon.com's recommender system utilizing user input to enhance recommendations.
    • Collective cognition emerges from individual sensory systems and environmental assistance to accomplish tasks (Example: construction worker referring to blueprints while using various materials).

Emergent Properties of Cognition

  • Example of emergence: A circle formed by children where no child embodies a complete circle.

Cognition as Manipulation of Representations

  • Representation: Refers to information that signifies something to an individual (e.g., a reminder or symbol).
    • Cognition involves the storing, encoding, and manipulating of information.
    • Representations are held in memory; cognition extends beyond living entities and applies to machines as well.
    1. Computer Method:
    • Image recognition via pixel series analysis.
    1. Animal/Human Method:
    • Visual perception is based on continuous stimulation of retinal neurons through light reflections.
    • Repeated exposure to the same images strengthens memory through neuron activation.
    • Example: Recognizing home through a familiar stimulus (wife's shoes at the door implying her presence).

Human Memory Structure

  • Memory Types:
    • Sensory Memory: Lasts less than 1 second, acts as a temporary storage akin to a scratch pad.
      • Example: Immediate recall, like responding in a brief conversation.
    • Short Term Memory: Lasts about 1 minute, operates as working memory before being consolidated into long-term memory.
      • Iconic Memory: Visual information just perceived.
      • Echoic Memory: Auditory information just perceived.
    • Long Term Memory: Retains information potentially indefinitely; challenging to retrieve but considered permanent.

Explicit vs Implicit Memory

  • Explicit/Declarative Memory: Conscious recollection of facts and events (e.g., appointments, past experiences).
    • Episodic Memory: Personal experiences, events.
    • Semantic Memory: General knowledge, factual information.
  • Implicit Memory: Unconscious recall necessary for skills and procedures.
    • Procedural Memory: Skills and tasks like driving or writing.

Neurobiological Basis of Memory

  • Confidence of memory locations remains unclear. The hippocampus is crucial for converting short-term to long-term memory.
  • Procedural memory relies on the cerebellum, basal ganglia, and motor cortex.

Memory in Software Systems

  • Computer Memory Models: Hash tables, schemata, frames, logical sentences along with disk/flash memory systems.
    • Activation patterns are instrumental in information processing.

Types of Learning

  • Learning adjusts memory to enhance future actions.
    1. Habituation: Decreased response to repeated stimuli.
    • Example: Initial jump from a loud noise eventually ceases with continued exposure.
    1. Sensitization: Signature increase in response to stimuli after repetition.
    • Example: Increased awareness of a vibrating phone based on familiarity.
    1. Conditioned Learning: Formation of associations between unrelated stimuli (e.g., Pavlov’s dogs learning to salivate at the sound associated with food).

Operant Conditioning Types

  1. Positive Reinforcement: Behavior increased due to positive outcomes (e.g., receiving a smile for holding a door).
  2. Negative Reinforcement: Behavioral increase to remove unpleasant conditions (e.g., baby stops crying once given candy).
  3. Positive Punishment: Decrease in behavior due to negative outcomes (e.g., touching a hot surface results in burns).
  4. Negative Punishment: Removal of positive stimuli leading to decreased behavior (e.g., loss of allowance after lying).
  • Mnemonic for Learning Models:
    • Positive: Present an element; Negative: Remove an element; Reinforce: Increase likelihood; Punish: Decrease likelihood.

Learning Mechanisms

  • Practice: Repetitive action leading to improvement (e.g., skill mastery).
  • Imprinting: Time-sensitive learning (e.g., duckling identifying mother figure).
  • Observational Learning: Learning through the observation of others (e.g., mimicking dance moves).
  • Testimony: Knowledge acquisition through verbal communication (e.g., learning tech skills).
  • Mentorship: Gaining knowledge through guidance (e.g., learning how to cook).

Cultural and Genetic Learning

  • Cultural Learning (Imitation): Adaptive behavior in rapidly changing environments (e.g., dietary practices).
    • Content Bias: Imitating effective practices (e.g., methods of composting).
    • Prestige Bias: Imitating successful individuals (e.g., following a celebrity’s trends).
    • Conformity Bias: Following common behaviors (e.g., social trends).
  • Individual Learning: Self-driven learning adapted based on the rapid pace of change.

Perception

What is Perception?
  • The interpretive process of sensory input leading to a coherent experience of reality, transforming raw information into meaningful representations.
Sensory Modalities
  • Typical sensory stimuli include light (vision), air vibrations (audition), and chemical signals (taste/smell). Atypical senses involve bodily sensations such as pain and temperature.
Visual and Auditory Perception
  • Human Vision:
    • Light focus forms images on the retina (rods and cones).
    • Rods: Highly sensitive for low-light conditions—critical for peripheral vision and motion detection.
    • Cones: Color-sensitive, function optimally in bright light.
  • Depth Perception: Conditioned by size, texture, occlusion, etc.
  • Audition (Hearing):
    • Acoustical signaling is analyzed by measuring sound localization via ear input disparities.
Cognition and Perception Modelling
  • Dorsal Stream: Guides motor outputs via visual inputs.
  • Ventral Stream: Helps with recognition and form representation.
Cognitive Science and Music
  • Role of Music: Cultural universality signifies music's relevance in emotion, social bonding, and cognitive function (psychology, creativity).
  • Evolutionary Theories of Music:
    • Spandrel Theory: Music as a byproduct with no direct survival benefit.
    • Adaptive Theory: Music promotes mate attraction and social cohesion.

Fields of Cognitive Science

  • Core: Psychology, Philosophy, Computer Science, Linguistics, and Neuroscience.
  • Secondary: Education and Anthropology.
  • Notable concepts:
    • Cognitive psychology studies mental functions and development.
    • Philosophy analyzes existence and cognition through normative reasoning.