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Describe Miller’s classic concept about the magical number 7 ± 2. Why are chunks relevant to this concept? Why was Miller’s emphasis different from the behaviorist approach? How did the Atkinson–Shiffrin model incorporate the idea of limited memory?
Miller proposed that short-term memory holds about 7±2 items, but these items can be “chunks,” meaning grouped units of information; chunking increases capacity by organizing data into meaningful patterns. His emphasis differed from behaviorists by focusing on internal mental processes rather than observable behavior.
The Atkinson–Shiffrin model incorporated limited memory by proposing a short-term store with strict capacity and duration limits, where rehearsal is needed to maintain information and transfer it to long-term memory.
What is the serial-position effect? Why is this effect related to short-term memory? Also discuss another classic method of measuring short-term memory.
The serial-position effect refers to better recall for items at the beginning (primacy) and end (recency) of a list. The recency portion reflects short-term memory because those items are still actively held at recall.
Another classic method is the Brown–Peterson task, which prevents rehearsal (e.g., counting backward) to measure how quickly information decays from short-term memory.
This chapter described an important study by Conrad and Hull (1964), which showed that people recall more letters from the sequence “C, W, Q, K, R, X” than from the sequence “C, T, D, G, V, B.” What does this study tell us about working memory? If you rehearsed these letters, what part of your brain would be most active?
The study shows that working memory is sensitive to acoustic similarity: letters that sound alike are harder to recall, suggesting that information is encoded phonologically in working memory.
If rehearsing the letters, the left hemisphere language areas, especially regions like Broca’s area, would be most active due to subvocal rehearsal processes.
Suppose that you have just been introduced to five students from another college. Using the information about semantic similarity, why would you find it difficult to remember their names immediately after they have been introduced? How could you increase the likelihood that you would remember their names?
Semantic similarity causes interference because similar-sounding or meaning-related names compete with each other in working memory, making them harder to distinguish and encode.
You could improve recall by using distinctive encoding strategies such as associating each name with a unique visual image, repeating names, or linking them to prior knowledge to reduce interference.
According to the discussion of Baddeley’s approach, working memory is not just a passive storehouse. Instead, it is like a workbench where material is continually being handled, combined, and transformed. Why is the workbench metaphor more relevant for Baddeley’s model than for the Atkinson–Shiffrin model?
Baddeley’s model involves active manipulation of information (e.g., central executive coordinating subsystems), so the workbench metaphor reflects ongoing processing. Information is transformed, integrated, and used dynamically.
In contrast, the Atkinson–Shiffrin model treats short-term memory more as a passive temporary storage system, emphasizing holding rather than actively working on information.
This chapter describes Baddeley and Hitch’s (1974) research on remembering numbers while performing a spatial reasoning task (the “A follows B” task). Why does this research suggest that a model of working memory must have at least two separate stores?
The study showed that people can perform a verbal memory task and a spatial reasoning task simultaneously with limited interference, implying separate systems.
This supports the idea that working memory must include at least two distinct stores (e.g., phonological loop and visuospatial sketchpad) rather than a single unified system.
Name some tasks that you have performed today that required the use of your phonological loop, the visuospatial sketchpad, the central executive, and the episodic buffer. Can you think of a specific task that uses all four of these working-memory components, as well as long-term memory?
Phonological loop: rehearsing a phone number; visuospatial sketchpad: navigating a route; central executive: planning tasks; episodic buffer: integrating a conversation with past knowledge.
A task using all four plus long-term memory could be driving while following spoken directions, recalling past experiences, visualizing the route, and coordinating attention and decisions.
What does the central executive do? With respect to its role in working memory, which tasks are similar to those of a business executive?
The central executive directs attention, allocates resources, switches tasks, and integrates information from subsystems and long-term memory.
Like a business executive, it prioritizes tasks, manages multiple operations, coordinates different departments (subsystems), and makes strategic decisions about resource use.
Turn to Figure 2.1. Using the descriptions that you have read in the current chapter, point out which parts of the brain are active for tasks that require (a) the phonological loop, (b) the visuospatial sketchpad, and (c) the central executive.
(a) Phonological loop: left hemisphere language areas, especially temporal and frontal regions. (b) Visuospatial sketchpad: occipital and parietal regions, primarily in the right hemisphere. (c) Central executive: frontal lobes, especially prefrontal cortex.
These areas reflect specialization for verbal processing, visual-spatial processing, and executive control respectively.
For many decades, researchers in the area of human memory primarily studied college students who are enrolled in introductory psychology courses. Why would the research on working memory not be applicable for a group of people who are currently experiencing major depression?
Depression affects attention, processing speed, and executive control, all of which are crucial for working memory performance. Thus, results from typical college samples may not generalize.
Individuals with depression may show reduced working memory capacity or efficiency, especially due to impaired central executive functioning and difficulty maintaining or manipulating information.
