Cognitive Psychology: Understanding Mental Processes

• Cognitive psychology aims to understand mental processes for interpreting the environment and making decisions.
• Cognitive psychology seeks to describe the function of these mental processes, often using flow charts.

Core Assumptions and Principles

• The information processing analogy compares the mind to a computer.
• The mind uses internal representations and processes them.
• Mental operations have limited capacity.
• Long-term memory stores representations that can be retrieved to compare to new inputs.
• Output occurs via a motor control system.

The Computational Metaphor

• The brain is like computer hardware, while cognition is like computer software.
• Sensory inputs are transformed into an internal code through internal representations.
• Mental processes perform operations on these internal representations.

Key Assumptions of the Computational Metaphor

• The mind uses symbolic representations, where internal representations stand for something else.
• There is a limited and well-defined set of symbols.
• These symbolic representations are stored in memory.
• Cognition is a product of operations, which are internal processes acting on symbolic representations.
• Operations are deployed based on rules stored in memory.
• Mental processes, like computer programs, transform representations.

Marr's 3 Levels of Description

• Computational Theory Level: Focuses on the function of cognition (What and Why).
• Representation and Algorithm Level: Focuses on how cognition works, including information storage and algorithms.
• Hardware Level: Considers how representations are instantiated in the real world.
• Cognitive psychologists are primarily interested in the computational and representational/algorithmic levels.

Modularity

• Human cognition is organized into discrete mental modules.
• Horizontal faculties: General competencies used across domains.
• Vertical faculties: Domain-specific cognitive functions.
• Modules can operate independently without interacting with other processes (information encapsulation).
• Damage to one module doesn't necessarily affect others.
• Modules are generally similar across individuals.
• Module processing is fast, obligatory and happens without conscious thought.
• Cognition involves both horizontal and vertical faculties.

Modularity and Input Systems

• Naming a face uses a visual module, memory to match the image, and a linguistic module to produce the name.
• There is a distinction between input systems (vertical faculties) and central processors.

Single Dissociation

• Single dissociation is shown when a manipulation affects one cognitive task but not another.
• It suggests that the two tasks involve at least partly different mechanisms.

Double Dissociation

• Double dissociation is shown when two cognitive functions can be impaired independently of each other.
• It indicates that two cognitive functions rely on separate brain function or systems.
• Task X is controlled by area A, and Task Y is controlled by area B.
• Single dissociation suggests some independence, but double dissociation confirms that two functions are separate.

Cognitive Neuropsychology

• Investigates what brain damage reveals about normal cognition.
• Focuses on reverse engineering cognition, with less emphasis on localization of function.
• Typically involves investigating single cases.

Patient HM

• Patient HM had neurosurgery to treat epilepsy.
• Patient HM developed severe anterograde amnesia.
• Patient HM could not form new memories after surgery.
• Patient HM had intact short-term memory and could learn new skills.
• HM case revolutionized the understanding of memory functions.

Limitations of Cognitive Neuropsychology

• It can be challenging to establish a patient's "normal" performance before injury.
• Brain plasticity and functional reorganization may lead to compensatory strategies.
• It's difficult to determine the time-course of information processing.
• Brain damage is often not focal, leading to overlapping deficits and heterogeneity among patients.

Summary of Core Concepts

• Thought is conceptualized as information processing.
• The goal is to understand mental processes.
• Cognition involves the storage and manipulation of internal representations based on rules.
• Cognitive processes are modular.
• Dissociations provide insight into modules.

Cognitive psychology explores the mental processes involved in understanding the environment and making decisions. It uses the information processing analogy, likening the mind to a computer. Mental processes operate on internal representations with limited capacity, and long-term memory stores representations for comparison with new inputs.