Chapter 5 Working Memory
What does the SUFFIX EFFECT reveal about the nature of echoic memory?
A demonstration called the "suffix effect" reveals something about the nature of echoic memory. Imagine you are a research participant in a memory experiment, and a list of random digits, letters, or the like is being presented to you. If the list is presented to you auditorily (as opposed to visually), and if there is an auditory recall cue such as a spoken word or specific item, recall of the last few items on the list is seriously hindered (Crowder, 1972). Researchers think the recall cue, called the suffix, functions as an auditory "mask" of sorts, because when the suffix is simply a beep or tone, or a visual stimulus, there is usually not much effect. Nor is there any effect if the items on the list are presented visually—say, on a computer screen. Finally, the more auditory similarity there is between the suffix and the items on the list, the greater the suffix effect.
What were the key findings from the Brown-Peterson task?
If not rehearsed, information is lost from STM in as little as 20 seconds. That length of time is called the retention duration of the memory. length of count down after trigram exposure. Both Brown and the Petersons interpreted this findingas meaning that the memory trace—the encoded mental representation ofthe to-be-remembered information that is not rehearsed—decays, or breaksapart, within about 20 seconds.
Why are the letters H.M. so important to our understanding of human memory?
Memory is localized. removed many structures on the inner sector of the temporal lobes of both sides of H.M.'s brain, including most of the hippocampus, the amygdala, and some adjacent areas He lost his ability to transfer new episodic memories into long-term memory. H.M. could remember semantic information and events that he had experienced several years before the operation. could no longer form new memories of new events, in addition to this anterograde amnesia (amnesia for new events), H.M. had retrograde amnesia (amnesia for old events) for the period of several years just before his operation
What did George Miller (1956) teach us about the capacity of STM? + Identify a means of increasing STM capacity
Miller (1956) reviewed evidence demonstrating that if you are presented with a string of random digits, you'll be able to recall them only if the string contains about seven or fewer digits. The only way to overcome this limitation is by somehow chunking the individ- ual units into larger units
What do ANTISACCADE and PROSACCADE tasks teach us about executive functioning and WM capacity?
One task studied by Kane, Bleckley, Conway, and Engle (2001) is called an "antisaccade" task. Research participants sit before a visual display and are asked to fixate their eyes in the middle of the screen. Then a stimulus (a letter to iden- tify) is presented briefly on one side or the other of the screen, forcing the partic- ipant to attend to that stimulus in order to make the proper response as quickly as possible. Now, just before that stimulus is presented, the experimenters flash a cue of some sort. Sometimes this cue is presented on the same side of the screen the stimulus will appear on. The authors call this the "prosaccade" task, because the cue presumably causes the participant to automatically look at (by moving his eyes sideways with a saccade) the correct side of the visual display. In this condition, no differences appeared in reaction time to identify the target let- ter for participants with either very high WM capacity or very low WM capacity. However, large differences arose in performance between high-WM and low-WM capacity in the antisaccade task, in which a cue appeared on the opposite side of the screen from where the target would appear. To perform op- timally at this task, the research participant had to resist the temptation to have his attention drawn to the misleading cue. Now, this is a tough temptation, and everyone shows slower reaction time in this condition, relative to the prosac- cade condition. However, the performance of low-WM-capacity participants was hurt more than that of high-WM-capacity participants.
What did the Brown-Peterson task teach us about DECAY and INTERFERENCE?
Participants are presented with a three-consonant trigram, such as BKG. They are also given a number, such as 347, and asked to count backward out loud by threes, at the rate of two counts per second, in time to a metronome. The purpose of the counting task is to pre- vent the participant from rehearsing the trigram. The length of time a partici- pant must count varies. If asked to count backward for only 3 seconds, roughly 80% of participants can recall the trigram. If asked to count for 18 seconds, this drops to about 7%. Both Brown and the Petersons interpreted this finding as meaning that the memory trace—the encoded mental representation of the to-be-remembered information that is not rehearsed—decays, or breaks apart, within about 20 seconds. Other cognitive psychologists soon began to challenge this decay explanation of forgetting. They proposed a different mechanism, called inter- ference, that worked as follows: Some information can "displace" other infor- mation, making the former hard to retrieve. maybe the counting task does more than prevent participants from rehearsing; it may actually interfere with their short-term storage of the trigram. As participants count aloud, they compute and announce the values. As they compute and announce the values, they put them into STM. Thus the counted values may actually be displacing the original information.
What does the HEBB RULE teach us about how brain regions change as memories are formed?
The Hebb rule states that if a synapse between two neurons is repeatedly activated at about the same time the postsynaptic neuron fires, the structure or chemistry of the synapse changes. A more gen- eral, and more complex, mechanism is called long-term potentiation. In this process, neural circuits in the hippocampus that are subjected to repeated and intense electrical stimulation develop hippocampal cells that become more sensitive to stimuli. This effect of enhanced response can last for weeks or even longer, suggesting to many that this could be a mechanism for long-term learning and retention (Baddeley, 1993b). As you might suspect, disrupting the process of long-term potentiation (say, through different drugs) also disrupts learning and remembering.
What is an icon?
The icon is a sensory memory storage system for visual material, holding information for up to about 1 second. The information it holds is in a relatively unprocessed form.-Sperling inferred, the icon holds information that has not yet been categorized, because Ps ability to report on "consonants and vowels" was equivalent in partial and whole reports.
Compare and contrast SHORT-TERM MEMORY and WORKING MEMORY
Their conception of STS was that it does more than merely hold onto seven or fewer pieces of information for a few seconds. In addition, they thought, information in STS somehow activates relevant information from LTS, the long-term store, and gathers some of that information into STS. They equated STS with consciousness and saw it as the location of various control processes that govern the flow of information, such as rehearsal, coding, integration, and decision making. STS is involved in transferring information to LTS, in integrating various pieces of information, and in keeping certain information available. -7 +/-2. about 20 seconds. Working memory - Found that just holding information in mind depletes cognitive resources. Therefore its not this independent memory system, its interconnected. working memory (WM). They see WM as consisting of a limited-capacity "workspace" that can be divided between storage and con- trol processing. Baddeley (1981, 1986, 1990) conceived of WM as consisting of three com- ponents, as depicted in Figure 5-8. The first is the central executive. This component directs the flow of information, choosing which information will be operated on when and how. the phonological loop, used to carry out subvocal rehearsal to maintain verbal material, and the visu- ospatial sketch pad, used to maintain visual material through visualization.
Understand why Sensory Memory is a form of MEMORY and not PERCEPTION.
This kind of memory has been described as a record of our percepts because it refers to the initial brief storage of sensory information. Thought to be more akin to memory than perception. Believe there is a separate sensory memory for each sense.
Understand the stages of Atkinson & Shiffrin's (1968) modal model of memory How do the stages differ from one another? How do they work together to explain memory?
This modal model of memory, assumes that information is received, processed, and stored differently for each kind of memory. Unattended information presented very quickly is stored only briefly in sensory memory. Attended information is held in short-term memory (STM) for periods of up to 20 or 30 seconds. Information needed for longer periods of time—the correct spelling of the words on tomorrow's test, for example, or the name of your fourth-grade teacher—is transferred to long-term memory (LTM),
Be familiar with Baddeley's Working Memory Model
Working Memory Model • Phonological Loop - Used to maintain information for a short time and for acoustic rehearsal • Visuo-spatial sketch pad - Used for maintaining and processing visuo-spatial information • Episodic buffer - Used for storage of a multimodal code, holding an integrated episode between systems using different codes • Central executive - Focuses attention on relevant items and inhibits irrelevant ones - Plans sequence of tasks to accomplish goals, schedules processes in complex tasks, often switches attention between different parts - Updates and checks content to determine next step in sequence
What did Saul Sternberg (1966,1969) teach us about STM search?
parallel search. Essentially, no matter what the number of titles is, you examine them at the same time, and it takes you no more time to com- pare Titanic to 1 title than to 10 titles. serial search. In our movie titles exam- ple, this would mean comparing Titanic to the first movie title on the list, then to the second title on the list, and so on, until you come to the last title. A self- terminating search stops when a match is found. Another kind of serial search is an exhaustive search, meaning that even if a match is found, you continue looking through every other item in the set. Sternberg 66 - presented with 7 #s held in STM, indicated readiness for next task. asked if letter was in initial memory set. Sternberg's (1966) results argue for serial, exhaustive search as the way we retrieve information from STM. Sternberg's explanation is that the search process itself may be so rapid and have such mo- mentum it is hard to stop once it starts. From a processing point of view, it may be more efficient just to let the search process finish and then make one deci- sion at the end, instead of making several decisions, one after each item in the memory set. STM treats ordered, organized material differently from unorganized material. Just as the chunking of digits or letters into more coher- ent patterns changes the apparent capacity of STM, using organized material also apparently affects the way it is processed.
How did Mora, Bates, and Barnett (1965) study echoic memory?
participants were given a "four-eared" listening task, similar to a dichotic listening task . They heard, simultaneously over headphones, four channels of incoming information, each apparently coming from a different location, consisting of a string of random letters. In one condition, participants were asked to report all the letters they had heard. In another condition, each participant held a board with four lights on it, each light corresponding to one of the channels, cueing the participant to report only the letters from a particular channel. Found that participants giving partial reports could report proportionately more letters. This suggests that the echo, like the icon, stores information only briefly.
Understand how primacy and recency are involved in the serial position effect.
people recall more words at either the beginning or the end of the list than they do words in the middle. This is known as the serial position effect. The improved recall of words at the beginning of the list is called the primacy effect; that at the end of the list, the recency effect. -participant's repetition of items, or rehearsal, is thought to help the items enter long-term storage. - Primacy effect disappears if not allowed to rehearse, though recency effect remains. -The recency effect is thought to result from participants' using either sensory memory or short-term memory. Participants often report that they can still "sort of" hear the last few words, and they often report these first and quickly.-if prevented from reporting words right away, by having participants perform a counting task, the recency effect disappears.
Be familiar with the experiment conducted by Sperling (1960) what were the key findings? what differed between the partial-report and whole-report conditions?
presented participants with displays containing letters, and asked them to recall the letters they saw. The displays were presented briefly, for only 50 milliseconds. Sperling found that, on average, people could report only 4 or 5 of the 12 letters presented, up to 500 milliseconds didn't approve performance. The problem wasn't percep- tual; 500 milliseconds, or half a second, is plenty of time to perceive something about all the letters. Found that performance improved when participants engaged in a partial-report technique. Ps heard tone which signaled which row to report. Regardless of tone, Ps were typically completely accurate. Suggests they must have stored the display because they did not know which two they would be reporting ahead of time. Were able to recall 75% more of letters than in the whole-report condition. Whole-report: participants lost the information in their memory during the time they took to report the first dew letters. -info fades away immediately. Delaying tone 1 sec, partial report performed no better than whole.
What is MASKING?
the icon can be "erased" by other stimuli presented immediately after the icon, a phenomenon known as masking. Report the letters which where in the same position as the circles! -circles erased memory of letters.
