Psychology Chapter on Short-Term Memory (STM)

Memory Systems Overview

• Memory is a multi-stage process with sensory memory, short-term memory (STM), and long-term memory (LTM).
• Short-term memory (STM) is crucial, and this chapter dives deep into its updated understanding: working memory.

Short-Term Memory (STM)

• STM holds a limited amount of information (approximately 7 ± 2 items) for a brief duration (15-20 seconds) without rehearsal.
• Capacity is increased by "chunking," or grouping information into meaningful units.
• STM decays quickly without active maintenance (rehearsal). Studies like Peterson & Peterson (1959) demonstrate this decay within 18-20 seconds.
• Encoding primarily involves converting visual information into auditory codes. This leads to similar-sounding word errors in recall.
• Errors often arise due to the similarity of sounds during recall, showcasing the role of sound in encoding.
• Proactive interference means previously learned information hinders encoding of new information in STM.

Working Memory (WM) - An Advanced Model

• Working memory (WM) is an active system for holding and manipulating information, encompassing STM but going further. It supports complex tasks like problem-solving, comprehension, and learning.
• WM consists of distinct components:
  • Phonological Loop: Handles verbal and auditory information; includes a phonological store and articulatory rehearsal to prevent decay (e.g., word length effect). Articulatory suppression disrupts verbal WM.
  • Visuospatial Sketchpad: Processes visual and spatial information, aiding in visual tasks like mental rotation.
  • Central Executive: Acts as the control center, manages attention, and integrates information from other components; involved in complex cognitive tasks.
  • Episodic Buffer: Links working memory to long-term memory and integrates information across different modalities, enhancing chunking.

Research on Working Memory

• Dual-task experiments show that WM has separate systems for verbal and visual processing, supporting independent subsystems (phonological loop and visuospatial sketchpad).
• Working memory capacity (WMC) varies between individuals and affects cognitive performance (reading, problem-solving, attention). Research by Daneman & Carpenter (1980) shows this correlation.

Neural Basis of Working Memory

• Prefrontal cortex (PFC) plays a crucial role in maintaining and manipulating information in working memory.
• Lesions in the PFC impair working memory, as demonstrated by Goldman-Rakic (1992) in monkeys.
• PFC neurons show sustained activity during delay periods in working memory tasks (Funahashi et al., 1989), providing biological support.

Real-World Applications and Everyday Examples

• WM is essential in numerous activities like mental arithmetic, following directions, and understanding language.
• Disorders like ADHD and dyslexia are often linked to deficits in working memory.
• Training studies, while showing potential, remain controversial regarding WM enhancement and long-term effects.

Summary

• STM is limited but can be enhanced by rehearsal/chunking.
• Working memory, with its components, provides a dynamic understanding of how the mind holds and manipulates information.
• WM's multifaceted nature plays a key role in complex cognitive processes.

This quiz explores the various aspects of short-term memory (STM) as part of the broader understanding of memory systems. Dive into concepts like capacity, chunking, and the effects of rehearsal on memory retention. Assess your knowledge on encoding processes and interference in STM.