Model Answer
0 min readIntroduction
Short-term memory (STM), also known as working memory, is the cognitive system responsible for temporarily holding and manipulating information. It’s a crucial component of our ability to learn, reason, and understand language. Initially, a single, unitary system was proposed to explain STM. However, as research progressed, limitations of this single-process view became apparent, leading to the development of dual-process theories. These theories posit that STM isn’t a single entity but comprises multiple interacting components. This answer will delineate the key distinctions between these two approaches, examining their theoretical underpinnings and empirical support.
Single-Process Theory of Short-Term Memory
The earliest and most influential single-process theory was proposed by Alan Baddeley and Graham Hitch in 1974. This model, initially developed as an alternative to the Atkinson-Shiffrin multi-store model, proposed a central executive and a passive slave system. The core idea was that STM functions as a temporary storage system with limited capacity. Information decays rapidly unless actively maintained through rehearsal.
- Central Executive: This component is responsible for allocating attentional resources and coordinating the activities of other subsystems.
- Phonological Loop: Deals with auditory and verbal information. It consists of a phonological store (holding information for a short duration) and an articulatory control process (allowing for subvocal rehearsal).
- Visuo-Spatial Sketchpad: Processes visual and spatial information.
Evidence supporting this theory came from studies on articulatory suppression (interfering with rehearsal reduces STM capacity) and word length effect (longer words are harder to remember due to limited rehearsal time). However, the original model struggled to explain how STM could simultaneously process different types of information.
Dual-Process Theory of Short-Term Memory
Recognizing the limitations of the single-process model, Baddeley and Hitch later refined their theory, leading to the development of the dual-process theory. This theory proposes that STM consists of two interacting systems: limited-capacity central executive and unlimited-capacity long-term memory (LTM).
- Central Executive: Remains the same as in the single-process model – responsible for attention allocation and coordination.
- Episodic Buffer: A new component added to bridge the gap between STM and LTM. It integrates information from the phonological loop, visuo-spatial sketchpad, and LTM, creating a unified episodic representation.
- Long-Term Memory (LTM): Acts as a vast storage system that provides information to the central executive when needed.
The dual-process theory explains how we can perform complex cognitive tasks that require simultaneous processing of different types of information. For example, remembering a phone number while simultaneously performing mental arithmetic. The episodic buffer allows for the integration of these different pieces of information. Evidence supporting this theory comes from studies showing that STM capacity can be increased when individuals utilize existing knowledge from LTM.
Comparative Analysis
| Feature | Single-Process Theory | Dual-Process Theory |
|---|---|---|
| Core Concept | STM as a unitary, limited-capacity store | STM as a system involving limited-capacity central executive and unlimited-capacity LTM |
| Components | Central Executive, Phonological Loop, Visuo-Spatial Sketchpad | Central Executive, Episodic Buffer, Phonological Loop, Visuo-Spatial Sketchpad, LTM |
| Role of LTM | LTM is largely separate from STM | LTM actively interacts with STM, providing information and context |
| Capacity Limits | Strictly limited by storage capacity | Capacity can be enhanced by utilizing LTM resources |
| Explanation of Complex Tasks | Limited ability to explain tasks requiring simultaneous processing | Better explains complex tasks through the episodic buffer and LTM interaction |
Conclusion
In conclusion, the evolution from single-process to dual-process theories of short-term memory reflects a deeper understanding of the complexities of human cognition. While the initial single-process model provided a foundational framework, the dual-process theory offers a more comprehensive and nuanced explanation of how we temporarily store and manipulate information. The inclusion of the episodic buffer and the active role of LTM address the limitations of the earlier model, providing a more accurate representation of the dynamic interplay between STM and LTM. Future research continues to refine our understanding of these processes, exploring the neural mechanisms underlying these cognitive systems.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.