Cognitive Psychology Unit 6 ReviewShort–term and Working Memory

Key Concepts

• Short-term memory (STM) temporary storage of information for a brief period of time (seconds to minutes)
• Working memory (WM) active manipulation and processing of information held in STM
  • Involves executive functions such as attention, planning, and decision-making
• Capacity of STM and WM limited to a small number of items (typically 7 ± 2)
• Chunking process of grouping related information into meaningful units to increase the amount of information that can be held in STM
• Maintenance rehearsal repetition of information to keep it active in STM
• Elaborative rehearsal associating new information with existing knowledge to facilitate long-term memory storage
• Central executive component of WM responsible for allocating attentional resources and coordinating information processing

Models and Theories

• Atkinson-Shiffrin model (multi-store model) proposes three separate memory stores: sensory, short-term, and long-term memory
  • Information flows from sensory memory to STM and then to long-term memory through rehearsal
• Baddeley and Hitch's multicomponent model of working memory consists of four components: central executive, phonological loop, visuospatial sketchpad, and episodic buffer
  • Central executive controls and coordinates the other components
  • Phonological loop stores and manipulates verbal and auditory information
  • Visuospatial sketchpad stores and manipulates visual and spatial information
  • Episodic buffer integrates information from the other components and long-term memory
• Cowan's embedded-processes model views WM as an activated portion of long-term memory rather than a separate system
  • Focus of attention holds a limited number of items (typically 4) in a highly accessible state
• Time-based resource-sharing (TBRS) model proposes that WM performance depends on the balance between processing and maintenance activities
  • Rapid switching between processing and maintenance allows for the refreshing of memory traces

Components of Working Memory

• Central executive attentional control system that manages and coordinates the other components of WM
  • Allocates attentional resources, selects relevant information, and suppresses irrelevant information
  • Involved in planning, decision-making, and problem-solving
• Phonological loop stores and manipulates verbal and auditory information
  • Consists of a phonological store (inner ear) and an articulatory rehearsal process (inner voice)
  • Plays a role in language acquisition, comprehension, and production
• Visuospatial sketchpad stores and manipulates visual and spatial information
  • Consists of a visual cache (inner eye) and a spatial mechanism (inner scribe)
  • Involved in mental imagery, navigation, and spatial reasoning
• Episodic buffer temporary storage system that integrates information from the other WM components and long-term memory
  • Creates a unified representation of multimodal information
  • Facilitates the transfer of information between WM and long-term memory

Capacity and Limitations

• STM capacity limited to approximately 7 ± 2 items (Miller's magic number)
  • Capacity can be increased through chunking, which groups related information into meaningful units
• WM capacity even more limited, typically around 4 items in the focus of attention (Cowan's magic number)
  • Capacity varies depending on the complexity and familiarity of the information
• Temporal duration of STM and WM limited to seconds or minutes without rehearsal
  • Information decays rapidly if not actively maintained or transferred to long-term memory
• Interference occurs when similar or competing information disrupts the storage or retrieval of target information
  • Proactive interference occurs when previously learned information interferes with the learning of new information
  • Retroactive interference occurs when newly learned information interferes with the retrieval of previously learned information

Encoding and Retrieval Processes

• Encoding process of converting sensory input into a mental representation that can be stored in memory
  • Involves attention, perception, and association with existing knowledge
  • Influenced by factors such as distinctiveness, elaboration, and organization of information
• Maintenance rehearsal repetition of information to keep it active in STM
  • Involves the articulatory rehearsal process in the phonological loop
  • Effective for maintaining information in STM but does not lead to long-term memory storage
• Elaborative rehearsal associating new information with existing knowledge to facilitate long-term memory storage
  • Involves deeper processing and the creation of meaningful connections
  • More effective than maintenance rehearsal for long-term retention
• Retrieval process of accessing and bringing information from memory into conscious awareness
  • Cued recall using external or internal cues to trigger the retrieval of specific information
  • Free recall retrieving information without specific cues, relying on associations and strategies

Factors Affecting Performance

• Attention plays a crucial role in WM performance
  • Selective attention focuses on relevant information while ignoring irrelevant information
  • Divided attention allocating attentional resources between multiple tasks or stimuli
  • Sustained attention maintaining focus on a task over an extended period of time
• Cognitive load amount of mental effort required to process and store information in WM
  • High cognitive load can lead to decreased performance and increased errors
  • Strategies such as chunking and automation can reduce cognitive load
• Expertise and familiarity with a task or domain can improve WM performance
  • Experts have more efficient encoding and retrieval processes due to well-organized knowledge structures
  • Familiarity with a task allows for the automation of processes, freeing up WM resources
• Emotional states can influence WM performance
  • Positive emotions (mild to moderate) can enhance cognitive flexibility and creative problem-solving
  • Negative emotions (high levels of stress or anxiety) can impair WM by consuming attentional resources

Experimental Evidence

• Dual-task paradigms demonstrate the limited capacity of WM
  • Performing two tasks simultaneously (one storage task and one processing task) leads to decreased performance compared to performing each task separately
• Neuroimaging studies (fMRI, PET) reveal the neural correlates of WM
  • Prefrontal cortex plays a key role in executive functions and the manipulation of information in WM
  • Parietal cortex involved in the storage and representation of information in WM
• Lesion studies provide evidence for the dissociation of WM components
  • Patients with lesions in the left hemisphere (Broca's area) show deficits in the phonological loop
  • Patients with lesions in the right hemisphere (parietal cortex) show deficits in the visuospatial sketchpad
• Individual differences in WM capacity correlate with performance on complex cognitive tasks
  • High WM capacity associated with better performance on tasks such as reading comprehension, problem-solving, and fluid intelligence
  • Low WM capacity associated with cognitive deficits and disorders such as ADHD and schizophrenia

Real-World Applications

• Education and learning strategies that optimize WM can enhance academic performance
  • Chunking information into meaningful units (mnemonic devices, acronyms) facilitates encoding and retrieval
  • Spaced repetition and active recall promote long-term retention and transfer of knowledge
• Cognitive training programs aim to improve WM capacity and executive functions
  • Computerized training tasks (n-back, complex span tasks) target specific WM components
  • Transfer effects to untrained tasks and real-world performance remain controversial
• Human factors and ergonomics consider WM limitations in the design of user interfaces and systems
  • Minimizing cognitive load and providing clear, concise information improves usability and reduces errors
  • Designing for intuitive navigation and consistent layouts reduces the demands on WM
• Clinical applications of WM research inform the diagnosis and treatment of cognitive disorders
  • WM deficits are common in conditions such as ADHD, schizophrenia, and age-related cognitive decline
  • Cognitive remediation therapies target WM and executive functions to improve daily functioning and quality of life