Chapter 5: Test Yourself Review Questions
Describe two findings that led Baddely to begin considering alternatives to the modal model.
1) STM and the modal model do not consider dynamic processes that unfold over time led Baddeley to begin considering alternative to the modal model 2) Baddely noticed that under certain conditions it is possible to carry out two tasks simultaneously
The beginning of the chapter makes the claim that "life is all memory". How has this claim been supported by considering what memory does for people with the ability to remember and what happens when this ability is lost, as in cases like that of Clive Wearing?
Memory is the processes involved in retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present. The fact that memory retains information that is no longer present means that we can use our memory as a "time machine to go back just a moment - to the words you read at the beginning of this sentence - or many years - to events as early as a childhood birthday party. We also use memory to remember what we need to do later in the day, to remember facts we have learned, and to use skills we have acquired. The list of things that depend on memory is an extremely long one because just about everything we do depends on remembering what we have experienced in the past. Clive Wearing, who contracted viral encephalitis, destroying parts of his temporal lobe important for forming new memories, now lives totally within the most recent one or two minutes of his life
What is the capacity of STM, and how is it influenced by chunking?
One measure of the capacity of STM is provided by the digit span. According to measurements of digit span, the average capacity of STM is about 5 to 9 items - about the length of a phone number. More recent measures of STM capacity have set the capacity at about 4 items. These estimates of either 4 items or 5 to 9 items set rather low limits on the capacity of STM. Miller introduced the concept of chunking to describe the fact that small units (like words) can be combined into larger meaningful units, like phrases, or even larger units, like sentences, paragraphs, or stories. Chunking in terms of meaning increases our ability to hold information in STM. We can recall a sequence of 5 to 8 unrelated words, but arranging the words to form a meaningful sentence so that the words become more strongly associated with one another increases the memory span to 20 words or more
Describe sensory memory and Sperling's experiment in which he briefly flashed an array of letters to measure the capacity and duration of sensory memory
Sensory memory is the retention, for brief periods of time, of the effects of sensory stimulation. George Sperling wondered how much information people can take in from briefly presented stimuli. He determined this in a famous experiment in which he flashed an array of letters on the screen for 50 milliseconds and asked his participants to report as many of the letters as possible. Procedure for three of Sperling's experiments: (a) Whole Report Method: person saw all 12 letters at once for 50 ms and reported as many as he or she could remember (b) Partial Report: person saw all 12 letters, as before, but immediately after they were turned off, a toe indicated which row the person was to report (c) Delayed Partial Report: Same as (b), but with a short delay between extinguishing the letters and presentation of the tone. The result of the delayed partial report experiments was that when the cue tones were delayed for 1 second after the flash, participants were able to report only slightly more than 1 letter in a row, the equivalent of about 4 letters for all three rows - the same umber of letters they reported using the Whole Report Method. Sperling concluded from these results that a short-lived sensory memory registers all or most of the information that hits our visual receptors, but that this information decays within less than a second
Describe the phonological similarity effect, the word length effect, and the effect of articulatory suppression. What do these effects indicate about the phonological loop?
The Phonological Similarity Effect: the confusion of letters or words that sound similar. The Word Length Effect: occurs when memory for lists of words is better for short words than for long words. Occurs because it takes longer to rehearse the long words and to produce them during recall Articulatory Suppression: repetition of an irrelevant sound preventing rehearsal
What is the central executive? What happens when executive function is lost because of damage to the frontal lobe?
The central executive is the component that makes working memory "working" because it is the control center of the working memory system. Its mission is not to store information, but to coordinate how information is used by the phonological loop and visuospatial sketch pad. Baddley describes the central executive as being an attention controller. It determines how attention is focused on a specific task, how it is divided between two tasks, and how it is switched between tasks One of the ways the central executive has been studied is by assessing the behavior of patients with brain damage. Patients with frontal lobe damage have problems controlling their attention. A typical behavior of frontal lobe patients is perseverations - repeatedly performing the same behavior even if it is not achieving the desired goal
What is the episodic buffer? Why was it proposed, and what are its functions?
The episodic buffer can store information (thereby providing extra capacity) and is connected to LTM (thereby by making interchange between working memory and LTM possible). The main "take-home message" about the episodic buffer is that it represents a way of increasing storage capacity and communicating with LTM
What are the differences between STM and working memory?
Working memory differs from Short-Term Memory in two ways: 1) STM is concerned with storing information for a brief period of time, 2) STM consists of a single component, whereas working memory consists of a number of components. Working Memory is concerned not just with how information is stored, but with how information is manipulated in the service of various forms of cognition
Describe evidence supporting the following types of coding in STM: auditory (Conrad letter memory experiment); visual (Della Sala matrix experiment); and semantic coding (Wickens fruits and professions experiment).
Coding refers to the way information is represented. Auditory coding involves representing items in STM based on their sound. One of the early experiments that investigated coding in STM was done by R. Conrad in 1964. In Conrad's experiment, participants saw a number of targets letters flashed briefly on a screen and were told to write down the letters in the order they were presented. Conrad found that when participants made errors, they were most likely to misidentify the target letter as another letter that sounded like the target. For example, "F" was most often misidentified as "S" or "X," two letters that sound similar to "F," but it was not as likely to be confused with letters like "E," that look like the target. Thus, even though the participants saw the letters, the mistakes they made were based on the letters' sounds; Visual coding involves representing items visually, as would occur when the details of a floor plan or the layout of streets on a map. This use of visual codes in STM was demonstrated in an experiment by Sergio Della Sala and coworkers, in which participants were presented with a task like the one in the following demonstration. The task in the demonstration involves visual coding in STM because the patterns are difficult to code verbally, so completing the pattern depends on visual memory. Della Sala presented his participants with patterns ranging from small (a 2 x 2 matrix with 2 shaded squares) to large (a 5 x 6 matrix with 1.5 shaded squares), with half of the squares being shaded in each pattern. He found that participants were able to complete patterns consisting of an average of 9 shaded squares before making mistakes; Semantic coding is representing items in terms of their meaning. An example of semantic coding in STM is provided by an experiment by Delos Wickens and coworkers. On each trial, participants were presented with words related to either (a) fruits (the "fruit group") or (b) professions (the "professions group"). Participants in each group listened to three words (for example, banana, peach, apple for the fruit group), counted backwards for 15 seconds, and then attempted to recall the three words. They did this for a total of four trials, with different words presented on each trial. The basic idea behind this experiment was to create proactive interference, the decrease in memory that occurs due to prior learning, by presenting words in a series of trials from the same category. On the first trial the average percent recalled was 86 percent, but performance dropped on trials 2, 3, and 4 as additional names of fruits were presented. Evidence that this interference can be attributed to the meanings of the words is provided by the results for the professions group. As with the fruits group, performance is high on trial 1 and then drops on trials 2 and 3 because all of the words are names of professions. But on trial 4, the names of fruits are presented. Because these are from a different category, proactive interference is reduced, which results in an increase in performance on trial 4. This effect is called release from proactive interference
What is the evidence supporting the idea that better comprehension, reasoning, and intelligence are related to having a larger and more efficient working memory?
Daneman and carpenter measured reading spans for 20 participants and also presented a comprehension test in which participants answered a question about a paragraph they had read. When they compared reading spans and performance on the comprehension test, they found that participants with larger reading spans performed better on the comprehension test. Many other experiments have obtained similar results, showing that better working memory scores are associated with better comprehension and also with better reasoning ability and higher intelligence. One idea about what this means is that people with better working memory capacity score better on these tests because there is more space in their working memory to hold and manipulate information. But another idea is that a person's working memory capacity reflects not only how many items can be stored, but how efficiently the person can focus attention on relevant information and filter out irrelevant information.
Is memory lost from STM by decay or by interference? Be sure you understand the Peterson and Peterson experiment and Keppel and Underwood's interpretation of it. What is the time span of STM?
John Brown in England and Lloyd Peterson and Margaret Peterson in the United States used the method of recall to determine the duration of STM. Peterson and Peterson found that their participants were able to remember about 80 percent of the letters after counting for 3 seconds but could remember an average of only 12 percent of the three-letter groups after counting for 18 seconds. They interpreted this result as demonstrating that participants forgot the letters because of decay. Why would memory become worse after a few trials? Keppel and Underwood suggested that the drop-off in memory was due not to decay of the memory trace, as Peterson and Peterson had proposed, but to proactive interference. Keppel and Underwood proposed that proactive interference is what caused the decrease in memory observed in the later trials of Peterson and Peterson's experiment. Thus, recalling the early letters in the list created interference that made it more difficult to remember the later letters in the list. The outcome of this constant interference is that the effective duration of STM, when rehearsal is prevented, is about 15-20 seconds.
Describe Baddeley's three-component model of working memory
Working memory accomplishes the manipulation of information through the action of three components: the phonological loop, the bisuospatial sketch pad, and the central executive. 1) The Phonological Loop: holds verbal and auditory information. 2) the Visuospatial Sketch Pad: holds visual and spatial information. 3) the Central Executive: pulls information from long-term memory and coordinated the activity of the phonological loop snd visiospatial sketch pad by focusing on specific parts of a task and switching attention from one part to another
Describe Atkinson and Shiffrin's modal model of memory, in terms of both its structure (the boxes connected by arrows) and the control processes. Then describe how each part of the model comes into play when you decide you want to order pizza but can't remember the pizzeria's phone number.
The stages in the model are called the structural features of the model. There are three major structural features: 1) sensory memory (an initial stage that holds all incoming information for seconds or fractions of a second) 2) short-term memory (holds 5-7 items for about 15-30 seconds) 3) long-term memory (can hold a large amount of information for years or even decades). Atkinson and Shiffrin also described the memory system as including control processes. Examples include (1) strategies you might use to help make a stimulus more memorable, such as relating the numbers in a phone number to a familiar date in history, and (2) strategies of attention that help you focus on information that is particularly important or interesting; When you want to order pizza, you first look at the screen, all of the information that enters you eyes is registered in sensory memory. You then use the control process of selective attention to focus on the number for whatever pizza restaurant your ordering from, which enters short-term memory and you use the control process of rehearsal to keep it there. Knowing you'll want to use the number again later, you decide that in addition to storing the number in your cell phone, you are going to memorize the umber so it will be stored in your mind. The process you use to memorize the number transfers the number into long-term memory, where it is stored. The process of storing the number in long-term memory is called encoding. A few days later, when one has an urge for pizza, they remember the number. This process of remembering information that is stored in long-term memory is called retrieval.
Describe the visuospatial sketch pad, the Shepard and Meltzger mental rotation task, and Brooks's "F" task. Be sure you understand what each task indicates about the visuospatial sketch pad.
The visuospatial sketch pad handles visual and spatial information and is therefore involved in the process of visual imagery. When Shepard and Metzler measured participants' reaction time to decide whether pairs of objects were the same or different, they obtained the relationship for objects that were the same. Based on this finding that reactions times were longer for greater differences in orientation, Shepard and Metzler inferred that participants were solving the problem by rotating an image of one of the objects in their mind. This mental rotation is an example of the operation of the visuospatial sketch pad because it involves visual rotation through space. Lee Brooks did some experiments in which he demonstrated how interference can affect the operation of the visuospatial sketch pad. Task 1 Visualize Block letter F, then point to the outer corners of the letter. Task 2 Visualize F again, but this time say 'out' or 'in' instead of pointing to out or in corners. Most people find that the pointing task is more difficult. The reason is that holding the image of the letter and pointing are both visuospatial tasks, so the visuospatial sketch pad becomes overloaded. In contrast, saying "out" or "in" is an articulatory task that is handled by the phonological loop, so speaking didn't interfere with visualizing the F
