Posts Tagged ‘Working memory’

Cognitive Neuroscience of Memory

September 6, 2019

The title of this post is the same as the title of an important book by Scott D. Slotnick. He writes in the preface, “The human brain and memory are two of the most complex and fascinating systems in existence. Within the last two decades, the cognitive neuroscience of memory has begun to thrive with the advent of techniques that can non-invasively measure human brain activity with spatial resolution and high temporal resolution.

Cognitive neuroscience had not been created when HM was a graduate student. The field is quite new. In cognitive psychology we studied cognitive processes, of which memory was central, but little was known about the neuroscience underlying memory.

Before getting into neuroscience it is important to understand what memory encompasses. Most people think of memory as something they need to use to pass exams, are frustrated by exam failures, and by an inability to remember names. Readers should be aware of the function of memory. Memory is a tool for time travel. We use it to help us predict and deal with the future. The more we learn, the more we have information for dealing with the future. Moreover, there are many types of memory.

The first pair of memory types is explicit memory and implicit memory. These refer to conscious memory and nonconscious memory. They differ in that all forms of explicit memory are associated with conscious experience/awareness of previously experienced memory, whereas all forms of implicit memory are associated with a lack of conscious experience/awareness of the previously experienced information.

Skills are one type of implicit of memory. After a skill is learned, performance of that skill reflects nonconscious memory. Once a person has learned to ride a bike, she doesn’t think about rotating the pedals, steering, breaking, or balancing. Rather, their conscious experience is dominated by where she wants to ride or whatever else she happens to be thinking about. Repetition priming is another type of implicit memory that refers to more efficient or fluent processing of an item when it is repeated. When a television commercial is repeated, that information is processed more efficiently (and when the item from the commercial is seen again while shopping, implicit memory presumably increases the chance that it will be purchased.) Skill learning can be assumed to be based on repetition priming.

The remaining memory types are types of explicit memory. A second pair of memory types is long-term memory and working memory. Working-memory is often referred to as short-term memory. A recognition memory experiment will be described to help make the distinction between long-term memory and working memory. During the study phase of both long-term memory and working memory, items such as words or objects are presented. After the study phase, there is a delay period that will last as a function of specific amount(s) of time. During the test phase, old items from the study phase and new items are presented, and participants make “old” or “new” judgments for each item. This is termed old-new recognition. A greater proportion of “old” responses to old items than “old” responses to new items indicates the degree of accuracy of the memories.

Long-term memory and working memory differ with regard to whether or not information is kept in mind during the delay period. Typically there are many items in the study phase and the delay period is relatively long (typically minutes to hours). Obviously participants do not actively maintain information from the study phase during the delay period. In working memory experiments, there are typically a few items in the study phase, the delay period is in seconds and participants are instructed to actively maintain information from the study phase in their mind.

Another pair of memory types is episodic memory and semantic memory. Episodic memory consists of the memories we have of our experiences. Semantic memory refers to retrieval of, hopefully, factual memory that is learned over periods of time such as the definition of a word. Unfortunately, semantic memory also consists of misinformation and erroneous beliefs. And, unfortunately, this misinformation and erroneous beliefs can be further amplified via technology and social media.

Another pair of memory types is “remembering” and “knowing.” “Remembering” refers to the subjective mental experience of retrieving details from the previous experience, such as someone retrieving where they parked their car in a parking lot. If any details are recalled from a previous experience, this constitutes “remembering.” “Knowing” is defined by the lack of memory for details from a pervious experience, such as when someone is confident they have seen someone before but not where or when they saw them. Remembering is usually assumed to be related to context memory, as it is thought to occur whenever contextual information is retrieved. “Knowing” is typically assumed to be related to item memory and semantic memory. The last pair of memory types is recollection and familiarity. The terms recollection and familiarity can refer to mathematical models of these two kinds of memory, but more commonly refer to all the forms of detailed memory (episodic memory, context memory and “remembering”) and non-detailed memory (semantic memory, item memory, and knowing). Dr. Slotnick writes, “It may be useful to think of context memory and item memory as measures of task performance, “remembering” and “knowing” as measures of subjective experience, and recollection and familiarity as general terms that describe strong memory and weak memory, respectively.”

Harmonizing Emotions and Thought

March 10, 2018

The title of this section is identical to the title of a section in Daniel Goleman’s book “Emotional Intelligence.” The hub of the battles or cooperative treaties struck between head and heart, thought and feeling are the connections between the amygdala (and related limbic structures) and the neocortex. This circuitry explains why emotion is so crucial to effective thought, both with respect to thinking clearly and in making wise decisions.

Working memory is the memory we hold in conscious thought. The prefrontal cortex is the brain region responsible for working memory. However, circuits from the limbic brain to the prefrontal lobes mean that the signals of strong emotion—anxiety, anger, and the like—can create neural static, sabotaging the ability of the prefrontal lobe to maintain working memory. This is why we say we “can’t think straight” when we are emotionally upset. Continual emotional distress can create deficits in a child’s intellectual abilities, and cripple the capacity to learn.

If subtle, these deficits are not always tapped by IQ testing. However, they do show up through more targeted neuropsychological measures, as well as in the child’s continual agitation and impulsivity. In one study, primary school boys with above-average IQ scores we still doing poorly in school. Neuropsychological tests found that they had impaired frontal cortex functioning. They were impulsive and anxious, often disruptive and in trouble. This suggested faulty prefrontal control over their limbic urges. In spite of their intellectual potential, they were at highest risk for problems like academic failure, alcoholism, and criminality—not because their intellect is deficient, but because their control over their emotional life is impaired. The emotional brain controls rage and compassion alike. These emotional circuits are sculpted by experience throughout childhood. We leave those experience utterly to chance at our peril.

Dr. Antonia Damaiso, a neurologist at the University of Iowa College of Medicine, has made careful studies of just what is impaired in patients with damage to the prefrontal-amygdala circuit. Their decision-making ability is terribly flawed. Still they show no deterioration at all in IQ or in cognitive ability. In spite of their intact intelligence, they make disastrous choices in business and their personal lives. They can even obsess endlessly over a decision so simple as when to make an appointment.

Dr. Damaiso argues that their decisions are bad because they have lost access to their emotional learning. The prefrontal-amygdala circuit is a crucial doorway to the repository of the likes and dislikes we acquire over the course of a lifetime. Cut off from emotional memory in the amygdala, whatever the neocortex mulls over no longer triggers the emotional reactions that have been associated with it in the past. Be it a favorite pet or a detested acquaintance, the stimulus no longer triggers either attraction or aversion. These patients have “forgotten” all such emotional lessons because they no longer have access to where they are stored in the amygdala.

This research has lead Dr. Damasio to the counter-intuitive position that feelings are typically indispensable for rational decisions; they point us in the proper direction, where dry logic can then be of best use.

So it is a mistake to do away with emotion and put reason in its place, as Erasmus recommended. We need to find the intelligent balance between the two. The old paradigm held an ideal of reason freed from the pull of emotion. The new paradigm urges us to harmonize head and heart. And to do that well in our lives means we must first understand what it means to use emotion intelligently.

Attention

December 2, 2017

This title is the same as a title in a book by Daniel Goleman and Richard J. Davidson, “Altered Traits:  Science Reveals How Meditation Changes Your Mind, Brain, and Body.”  William James, the founder of American psychology wrote: “The faculty of bringing back a wandering attention over and over again is the very root of judgment, character and will; an education which should improve this faculty would the the education par excellence.”

At its root meditation retrains attention, and different types boost varying aspects of attention. MBSR strengthens selective attention, while long-term vipassana (analytic meditation will be described later in the series of posts) practice enhances this even more. Five months after a three-month shamantha retreat meditators had enhanced vigilance, the ability to sustain their attention. But the beginnings of this enhancement also showed up after just seventeen minutes of mindfulness in beginners. This was no doubt a transitory state for the newcomers, and a more lasting trait for the experienced meditators. The same practice-makes perfect maxim likely applies to some other quickie meditation: just ten minutes of mindfulness overcame the damage to concentration from multi-tasking—at least in the short term; only eight minutes of mindfulness lessened mind-wandering for a while. About ten hours of mindfulness over a two-week period strengthened attention and working memory. This also led to substantially improved scores on the graduate school entrance exam. Although meditation boosts many aspects of attention, these are short-term gains; more lasting benefits require ongoing practice.

Cognitive Control Limitations

September 15, 2017

This is the sixth post based on “The Distracted Mind: Ancient Brains in a High Tech World” by Drs. Adam Gazzaley and Larry Rosen. A brief summary of cognitive control limitations follows.

Selectivity is limited by susceptibility to both internal and external influences. Only one source can be selected. It takes attention to disregard both internal and external sources that are external to what you’ve selected. This is why libraries are kept silent. Extraneous external sources require attention to be filtered out. This also involves internal sources. For example, you might be trying to concentrate on your homework, but you keep thinking about your upcoming date. Most meditation begins with focusing on your breath and perhaps a word or phrase and ignoring extraneous thoughts and extraneous stimuli.

Distribution of attention results in diminished performance compared to focused attention. This focusing requires attentional effort.

Sustainability of attention over time is limited, especially in extended boring situations. Although multitasking situations are not boring, there is the tendency to switch attention rather than to attend to what one is currently attending.

There are processing speed limitations that affect both the efficiency of allocation and withdrawal of attention.

Our working memory capacity is severely limited as to the number of items that can be held in working memory. The magic number 7 plus or minus 2, is closer to 5 plus or minus 2, and the limit can be as small as one depending on the nature of the information.

The fidelity, or quality of information maintained in working memory, decays over time and as a result of interference.

Multitasking is limited by our inability to parallel process two attention demanding taks. In reality task switching is required, which results in costs to accuracy and speed performance.

Although these are the same limitations homo sapiens have always had, they become much more pronounced due to the way we use our current technology. Moreover, this technology keeps multiplying, which exacerbates this problem further.

© Douglas Griffith and healthymemory.wordpress.com, 2017. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

 

Cognitive Processes

September 13, 2017

This is the fourth post based on “The Distracted Mind: Ancient Brains in a High Tech World” by Drs. Adam Gazzaley and Larry Rosen. The authors note that “‘Attention’ is likely the most widely used term in cognitive science.” Attention is also used widely by the general public and practitioners from diverse fields of education, philosophy, mental health, marketing, design, politics, and human factors.

To understand what attention means in cognitive science, its most fundamental feature is selectivity. Selectivity is required because attention is limited. Indeed, it is one of our must fundamental constraints. So we need to be selective to use this limited supply where it is most needed. It can be thought of as the spotlight in our cognitive control toolkit. Selective attention also involves suppression of perceptions that are outside of the spotlight. This is also known as the act of ignoring. What is not so well known is that this suppression requires attention which further depletes the limited supply. The amount of suppression required depends on extraneous stimuli in the immediate environment. And it also entails the suppression of thoughts extraneous to what is in the spotlight. Expectation also play a role here as we used our expectations to direct our attention. Expectation is what allows us to transition from the internal world of our goals to our perceptions and actions. Expectation is a critical factor in optimizing our performance by enabling knowledge of past events to shape our future. To a large extent our brains live in the future, using predictive information to bias both incoming stimuli and outgoing responses.

Directionality is another important feature of selective attention, We can direct our limited cognitive resources to stimuli in the environment, but we can also aim it internally at our thoughts and emotions. As in the case for external selective attention, our ability to control internal attention allows us to attend to relevant or ignore irrelevant information in our minds based on our goals. We can direct our attention toward searching memories and/or focusing on feedback from the body, such as a hungry stomach. It is often important to selectively ignore internal information such as suppressing sadness at a time when you need to remain upbeat, or suppressing a recurrent that is interfering with your current activities.

Another critical factor when using selective attention is our ability to sustain it. This is especially true in situations that are not engaging, or boring. Moreover, over time activities that once were engaging can become boring. Vigilance is the area of research concerned with looking for a signal over a long period of time.

Working memory refers to the amount of information we can hold in our active memory at the same time. This amount of information is limited. The exact amount is dependent on the items. George Miller’s original estimate was seven items plus or minus two. Over time this magic number has decreased. It might even be as small as one, depending on the nature of the information. We must keep thinking about or rehearsing this information to maintain it in working memory. And this is another strong constraint in our cognitive abilities.
Goal management is required when we have more than one goal. So when we engage in more than one goal-directed activity at a time, we are switching back and forth between multiple goals, we are multi-tasking. It is more accurate to call multi-tasking task switching as we can only perform one task at a time. We accomplish multi-tasking by rapidly switching between or among tasks, and this switching requires attention. There is also a requirement to review where we are in the goal to which we have switched back.

All tasks require cognitive control. Even if two tasks are not competing for the same sensory resources, mental task switching is required, with perhaps the requirement to determine where we were when we left that task.

The Signatures of Conscious Thought

April 5, 2016

“The Signatures of Conscious Thought” is the fourth chapter of “Consciousness and the Brain:  Deciphering How the Brain Codes our Thoughts” is an outstanding book by the French neuroscientist Stanislas Dehaene who is the Chair of Experimental Psychology at the College of France.  This is the fifth consecutive post on this outstanding book.  In this chapter Dr. Dehaene discusses four reliable signatures of consciousness—physiological  markers that index whether the participant experienced a conscious percept.

The first signature is a sudden ignition of parietal and prefrontal circuits that is caused by a conscious stimulus (remember that the participant indicates whether the stimulus is conscious).

The second signature is found in the EEG in which conscious access is accompanied by a slow wave called the P3 wave, which emerges as late as one-third of a second after the stimulus.

The third signature is the result of conscious ignition that also triggers a late and sudden burst of high frequency oscillations.

The fourth signature  consists of many regions exchanging bidirectional messages over long distances in the cortes, which form a global brain web.

The conscious brain can perceive only a single chunk at a time.  Working memory rehearses these chunks to keep the active so they can be further processed.  The processing of a second chunk can be delayed if it occurs prior to the processing of the first chunk.  This is known as the psychological refractory period.

We can process a stimulus before we become consciously aware of the stimulus.  For example, if we place a hand on a hot stove, we’ll take it off the stove before we consciously perceive the pain caused by the hot stove.

Consciousness lives in  loops of reverberating neuronal activity, circulating in the web of our cortical connections, causing our conscious experience.

fMRI and scalp recording of brain potentials catch just a glimpse of the underlying brain activity.  Explorations of the third and fourth signatures require electrodes being placed directly inside the brain.  Such implantations of electrodes are indicated for certain epileptic patients, so science can capitalize on victims of this unfortunate malady.  I hope it provides some satisfaction to these patients that the data that is derived from these electrodes is greatly advancing science.

Subliminal stimuli can propagate  deeply into the cortex, but this brain activity is strongly amplified when the threshold for awareness is crossed, thus yielding reliable and valid signatures of consciousness.

Five Constructs for Executive-Related Cognitive Abilities

February 18, 2015

This post addresses five constructs, or factors, dealing with executive related cognitive abilities.  They are obviously important because these are cognitive abilities at the executive level.  They also have special relevance for aging memory.  These factors play an important role in the assessment of Independent Activities of Daily Living (IADL).  IADL plays an important role in determining whether individuals are capable of living independently.  These factors are working memory, inhibition, executive at the attention, problem solving, and fluency.  Each factor will be briefly explained and discussed with respect to the healthy memory blog, “The Myth of Cognitive Decline.”

The most common example given of working memory is trying to remember a phone number you have just be given or read until it is dialed.  This is the magic number of 7 plus or minus two that has been revised down to five plus or minus two.  Actually, the size of the individual items affects the number that can be remembered.  Information must be rehearsed or actively used  or the information will be lost.  As the “Myth of Cognitive Decline” is addressing the phenomena of long term memory, working memory is not part of the myth.  Working memory does tend to decline as we age, although research has been done to demonstrate that it can be enhanced.

Inhibition refers to irrelevant information coming to mind when you are trying to remember or solve a problem.  This does increase as we age.  And it is the large amount of information held in long term memory that the “Myth of Cognitive Decline” addresses, that is likely increasing inhibition.  Simply put, there is more information to serve as the source of inhibition.  Given enough time, this inhibition can be overcome.

Executive attention refers to the managing and selection of information in trying to perform some task or to solve some problem.  The problem here for us as we age is that there is more information to attend to.  Again, given enough time, decreases in this ability can be overcome.

Problem solving refers to the marshaling of attention to solve  a problem.  Examples of problems addressed with IADL are planning a meal, planning a trip, managing finances, and so forth.  Although the more experienced mind has more information to solve problems, when there are time constraints, the additional information can be a problem as captured in the statement, “too much knowledge for one’s own good.”

Fluency is the ability to generate ideas or certain types of words (words beginning with “q”, vegetables, and so forth).  Here the older brain is at an advantage, but again, the pressures of time constraints can create problems.  A caveat to the “Myth f Cognitive Decline” is “given enough time.”

Recall, particularly of information from longer term memory, often involves problem solving.  When trying to remember the forgotten name of a particular actor for example, one might try to remember the movies the actor was in, the dates of the movies, and other actors.  Sometimes remembering a particular sound can help in the generation of candidate names.  What is interesting about these attempts is that the memory will suddenly pop into mind hours or days later.  Apparently memory search has been continuing in our non-conscious minds.  This is one of the reasons I think that these periodic memory searches contribute to memory health.  When we do these searches we are activating long unused memory circuits and reactivating them.  I have no carefully controlled research to back up my conjecture, but I think it is a compelling conjecture.  Perhaps some graduate student will undertake this research for a Master’s Degree or Ph.D.

© Douglas Griffith and healthymemory.wordpress.com, 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Making Working Memory Work for Older Adults

October 25, 2014

This blog post is taken from the article in Psychological Science (8 October 2014 DOI: 10.1177/095679761458725) by Julia Karbach and Paul Verhaeghen titled “Making Working Memory Work: A Meta-Analysis of Executive-Control and Working Memory Training in Older Adults.” It examined the effects of process-based executive-function and working memory training in older adults (>60 years). This analysis included 49 articles and 61 independent samples. This is an extremely important article for a couple of reasons. Weaknesses in the cognitive performance of older adults have been localized to fluid intelligence, the activities that involve executive control and working memory. As we know from the healthymemory blog post “The Myth of Cognitive Decline” the crystalized intelligence of older adults holds steady and even grows. The sometimes apparent slowness in recall and the difficulty in recalling certain items is due to the enormous amount of information that has accumulated in memory. Most, if not all, of those memories are available if not accessible and will pop into memory at some later time.

The second reason that this article is so important is that it is a meta-analysis of the relevant literature. A meta-analysis is a review and synthesis of the research. And it is the most impressive meta-analysis I have every read. It uses a sophisticated quantitative methodology, one that circumvents the problems noted in the healthymemory blog post, “Most Published Research Findings are False.” This meta-analysis can be regarded as a Gold Standard for meta-analyses.

So the conclusion is clear that these interventions do improve cognitive functions in the aging brain. Moreover, older people benefit just as much as younger people. Previously found age differentials do not maintain.

As an item for future research the authors argue that follow-up research should address the question as to whether the benefits of these interventions will hold over time. Frankly I find this question to be naive and unnecessary. The answer depends on whether these individuals continue to exercise their capabilities after the formal training ends. If someone takes golfing lessons and then does not play golf, would it be surprising if golfing skill declined? If someone learns to play a musical instrument and then no longer plays once the lessons have stopped, would it not be expected that performance on the instrument would decline. So the answer to the questions depends on whether the individual continues to be cognitively engaged and continues to engage in effortful learning (see the healthymemory blog post “The Adult Brain Makes New Neurons and Effortful Learning Keeps Them Alive.”

This is the constant theme of the healthymemory blog. Stay both cognitively and socially engaged and continue to learn till the very end.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

What Are the Atoms of Memory?

August 8, 2012

If you answered, “neurons,” you get partial credit. You need to remember the earlier Healthymemory Blog Post, “Glial Cells and Short Term Memory.” So neurons and glial cells are the atoms of memory. However, memories are not allocated to single neural or glial cells. Many years ago, the psychologist Karl Spencer Lashley published a report, “In Search of the Engram1” He would train animals to perform a specific task. Then in a series of experiments he would systematically remove different segments of cortex. Much less finding the engram in specific neurons, he was unable to locate specific areas of the associative cortex in which memories were stored. Let me stress associative cortex. If portions of the sensory cortex are removed, then the sense specific to that area of the cortex will be lost or seriously degraded. There are also subcortical structures, such as the hippocampus, that are important for the processing of memories.

Apparently memories are stored in patterns of firing among the circuits of neurons and glial cells. So memory circuits are established. The more they fire, the stronger they become, and more connections are established with other memory circuits. In this manner, one thought or memory leads to another. Many of these firings are below the level of consciousness. But your mind does manage to tap into some of them, and they constitute your flow of conscious thought. This can be regarded as short term or working memory. There is some question as to whether circuits in long term memory decay or are permanent. This is difficult to answer. Surely, you have experienced times when you knew you knew something, but could not recall it. This is called the Tip of the Tongue phenomenon. Later the desired item will suddenly pop into memory.

Generally speaking, I think it is a good idea to make a practice of recalling old memories. This puts you in touch with your past and prior knowledge. Even when you give up consciously trying to recall something, your subconscious will likely keep working to find it. Then, at an unexpected time, it can suddenly pop into consciousness. Unless you are working under time constraints, when you cannot recall something, it is best not to fall back on transactive memory immediately (that is, look it up or search for it, or ask someone), as your subconscious will likely keep working looking for it. This process of searching might well activate unused memory circuits.

A complicated experiment reported in Scientific American Mind2 done using mice came up with the estimate that on the order of 10,000 interlaced neurons in one very specific area of the brain is sufficient to form an engram, a specific memory. It is not yet known whether these interlaced neurons are necessary for the memory, or whether their removal will obliterate the memory.

1Lashley,K.S. (1950). In Search of the Engram. Society of Experimental Biology Symposium. 4, 454-482.

2Kock, C. (2012). Searching for the Memory. Scientific American Mind, July/August, 22-23.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Forgetting Is Important to a Healthy Memory

March 14, 2012

The common complaint is forgetting. Consequently the importance of forgetting is overlooked. A recent article1 provides a strong reminder of the importance of forgetting. The famous study of someone who remembered everything he experienced or tried to remember is recounted in a book by the Russian psychologist Alexander R. Luria, The Mind of a Mnemonist. Although this person made a good living giving demonstrations of his phenomenal memory, he regarded his exceptional talent as a curse. He wanted to forget, but he could not. His was truly a pathological case.

Traumas, in particular, and unpleasant thoughts, are things we want to forget. There unwelcome recall makes our lives unpleasant and can lead to depression and serious mental problems. We should all be aware of the benefits of optimism, and these memories make it difficult to be optimistic.

Fortunately, we can learn to forget and Michael Anderson and his colleagues have developed an experimental paradigm that not only shows that we can, but shows how to forget more effectively.2 Here’s how the experiment works. The first stage is simple paired associate learning. Words are paired and the research participants learn to recall the second word when the first word is presented.

In the second stage some of these same word pairs are presented and the research participants are asked to think about the second word when the first is presented. However some of the word pairs are presented and the research participants are asked not to think about the second word when the first word is presented. And some of the word pairs are not presented and serve as controls for the third stage of the procedure.

In the third stage the research participants are given the first word of all the three sets of the word pairs that have been presented. The word pairs in which the research participants were asked to think about both words in the second stage recalled the most words. The word pairs in which the research participants were asked not to think about the second word remembered the fewest words (showed the most forgetting) and the word pairs that were not presented during the second stage were recalled second best. So even those words that were seen less than the words with the forget instructions were better remembered. It is also interesting to note that forgetting increases as a function of the number of “not think” trials. So we can control our forgetting.

According to the theoretical account of these results that have been substantiated by brain imaging studies, the prefrontal cortex is the executive control area that inhibits the activity of the hippocampus, which is a primary subcortical structure for learning and apparently also for forgetting.

You might still be curious as to how to make yourself forget things you don’t want to remember. Well, technically you are not forgetting them. Rather you are instructing yourself not to think about them, so they will not pop up unwanted in your consciousness. In the experiment the research participants were implicitly recalling the words but instructing themselves not to think about them. This led to the nonintuitive finding that the more times they did this, the less likely they were to recall them.

Anderson and his colleagues have also presented research indicating that our ability to exercise this voluntary forgetting declines as we age.3 However, other research has failed to find this result and concluded that there was no difference in the ability to forget between old and young research participants4. The only difference I could find between the two studies, besides the second study using German research participants, and the first study using U.S. research participants, was that the elderly research group was slightly older in the U.S. than in the German study.

Regardless, I am not impressed by research showing that older research participants perform more poorly than younger research participants without providing any suggestions as to how the deficit might be remediated. Given the importance of the prefrontal cortex for deliberate forgetting I would suggest the possible benefit of exercising the prefrontal cortex (See the Healthymemory Blog post, “Improving Working Memory”).

1Wickelgren, I. (2012). Trying to Forget. Scientific American Mind, January/February, 33-39.

2Anderson, M.C. (2009). Suppressing Unwanted Memories, Current Directions in Psychological Science, 18, 189-194.

3Anderson, M.C., Reinholz, J., Kuhl, B., & Mayr, U. (2011). Psychology and Aging, 26, 397- 405.

4Alp, A., Bauml, K-H, & Pastotter, B. (2007). No Inhibitory Deficit in Older Adults’ Episodic Memory, Psychological Science, 18, 72-78.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Improving Working Memory

January 15, 2012

As readers of the Healthymemory Blog well know, the primary constraint on cognitive performance is our limitation in working memory. The simplest way of thinking about working memory is that it is the information you can hold at one time. Phone numbers are a common example, although they are less relevant with today’s technology than they use to be. But suppose someone shouts out a phone number you want before you can get to your desk and either write it down or dial it. It is likely that you will need to keep rehearsing the number or it will be forgotten before you return to your desk. Phone numbers might appear to be trivial, but working memory limits the number of ideas you can keep active in your memory at one time. In other words, it limits the number of things that you can actively think about at the same time. Unfortunately, working memory is a function that tends to decline as we age. The dorsolateral prefrontal cortex is the physiological substrate where working memory takes place. It requires glucose to operate. As working memory improves, the rate of glucose metabolism decreases (that is, the dorsolateral prefrontal cortex functions more efficiently).

Given the importance of working memory, exercising it to improve its efficiency is highly recommended. Fortunately, there are exercises that do just that. Paul Verhaegen published a paper titled “A Working Memory Workout: How to Expand the Focus of Serial Attention from One to Four Items in 10 Hours or Less” published in the Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 30. no.6, 2004. Suppose you toss a handful of coins, somewhere between 10 and 15, and then count the number of pennies, nickels, dimes, and quarters. The easiest way to do this is to count each denomination before moving to the next. Unfortunately, this places minimal demands on working memory. If you want to expand your working memory, begin by tossing two denominations of coins. Rather than counting them systematically, count them randomly removing each coin as you count it. Here you need to keep a running count of each denomination in working memory. This should be easy, but do this until you can count each denomination without error. Then move on to three denominations. This will place much greater demands on working memory as you need to keep track of three tallies. Keep doing this until you can do it accurately consistently. This might take some time, multiple days, weeks even. When this is mastered move on to four denominations and keep working until you can keep count of four denominations accurately. This will probably take even more time. But once you reach this point you will have reached what is currently as the capacity of working memory, four items. You can be proud to have a highly efficient dorsolateral prefrontal cortex.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Conscious Thought

August 14, 2011

The topic of consciousness has been addressed in a number of Healthymemory Blog Posts (“Change Your Brain by Transforming Your Mind,” “We Are the Law: Free Will, The Human Mind, and the Limits of Determinism,” “Consciousness and the Grandmother Cell,” “Fluid Intelligence and Working Memory,” “What is Incubation,” “How Do We See,” “Brain, Mind, and Body,” “What is Consciousness,”, and “Attention”) because it is an important topic. For most lay people, consciousness is psychology. It is how we deal with the world on a daily, and nightly, basis. It is a tad ironic, that for many academic psychologists consciousness is an epiphenomenon that we view in our minds, and that most, if not all, behavior and thought occur below the level of consciousness. So consciousness is viewed by some as a movie we see in our head as we proceed through our life. The believe it has no real function.

Consequently, it was refreshing to hear the presentation by Ray F. Baumeister at this year’s annual meeting of the American Psychological Association (APA) titled the “What, Why, and How of Consciousness.”1 Most theories that contend that consciousness is epiphenomenal focus on input and or output processes. Baumgartner does not address these theories as for him the role of consciousness is central to what occurs between input and output processes. He argues that conscious thought is for internal processing that facilitates downstream interaction with the social and cultural environment. Consciousness enables the construction of meaningful, sequential thought. These constructions are found in sentences and narratives, logical reasoning, quantification, causal understanding, and narratives. In short, it accounts for intellectual and social life. It is used for the simulation of events.

It is estimated that people focus an average of 30% to 40% of their thoughts on concerns that are unrelated to their present behavior. Some people’s minds wander from the here and now more than 90% of the time. Even when tied to present behavior, conscious thoughts are often used for to recall similar behaviors from the past, anticipating the consequences of present behaviors, or considering alternative courses of action.

Baumeister contends that thought sequences resemble film clips that the brain makes for itself, allowing different parts of the brain and mind to share information. The production of conscious thought is linked to the production of speech, because the human mind evolved to facilitate social communication and information sharing. This led to culture and the adaptive success of humankind as the social species.

1Although it might be difficult obtaining this address, much of its content and the citations found in this blog post can be found in “Conscious Thought Is For Faciliting Social and ‘Cultural Interactions: How Mental Simulations Serve the Animal-Cultural Interface” by Roy F. Baumeister and E.J. Masicampo in the Psychological Review, (2010), 117. 945-971.

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Improving Cognition

June 16, 2011

Improving Cognition was the title of the presentation John Jonides made as his William James Fellow Award address at this year’s meeting of the Association for Psychological Science (APS). The specific cognition Jonides sought to improve was fluid intelligence (see the blog post “Fluid Intelligence and Working Memory”). Typically intelligence is broken down into two generic types: crystalized intelligence and fluid intelligence. Crystalized intelligence is comprised of everything we know. This component of intelligence, absent pathology, typically remains intact as we age. As we age, it might take longer to remember certain information, but we typically can recall it given enough time and cues. Fluid intelligence is the component that deals with processing new information and novel problems. Fluid intelligence consists of the capacity of working memory (the amount of information it can hold at one time) and the attentional processes that work on this information and solve the novel problems. It is this component of intelligence that tends to decline as we age.

Jonides reported a program that after seventeen days of training produced an average gain of six IQ points in fluid intelligence. I will not get into the specifics of the training program, but it was quite demanding . The general characteristics of this program were as follows. It energized all processes of working memory. It did not use material specific processes. Task difficulty was increased as performance became better. However, performance needed to reach a stable level before difficulty was increase. If performance fell, then the task difficulty was decreased. Practice periods were spaced.

fMRI of the brains of research participants was also done. The trained regions brain requied less blood flow indicating that the trained brains had become more efficient.

This was great news, but the question remains whether this training can remediate age-related loss in cognitive skills. Jonides intends to address this question in future research. I think we can count on him following through on this research. He is a baby boomer so this research is of personal significance to him.

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Fluid Intelligence and Working Memory

January 23, 2011

Regular readers of the Healthymemory Blog should be familiar with the distinction between fluid and crystalized intelligence. Crystalized intelligence basically is a matter of what you know. Your vocabulary, for instance, reflects your crystalized intelligence. On the other hand, fluid intelligence reflects how well you deal with novel situations or solve novel problems. Absent pathology, crystalized intelligence does not decline significantly when we age. Fluid intelligence does decline with age. At times, crystalized intelligence can compensate for fluid intelligence. But ways of stemming losses in fluid intelligence as we age represent an important research problem.

Working memory refers to the information we can work with in what can be regarded as consciousness. In other words, it represents what we commonly experience as thinking. Working memory capacity has been found to bear a strong relationship to fluid intelligence. Now working memory itself can be divided into two factors: they are the number of components that can be maintained in working memory and the quality of those components. Recent research1 has indicated the role played by each of these factors. In a very clever, but complicated, experiment researchers were able to ferret out the respective contribution of each of these factors. They discovered that it was the number, and not the quality of the representations that played the important role in fluid intelligence.

Suppose that you are trying to solve some problem. There are a number of factors and potential hypotheses that need to be considered. How many of these can you keep in working memory at the same time. Of course, you can use transactive memory (write them down) to record the items that you cannot keep in working memory at the same time, but to bring them into working memory you need to move something out of working memory. So it would seem to be advantageous to be able to keep as many factors in mind at the same time when exercising your fluid intelligence. Now the quality of these representations is not important. So there might be an item with such poor resolution that you cannot recall what it is, but you know that it exists. Here you can use transactive memory to increase the resolution of the item. The important consideration for fluid intelligence was that you remembered that there was something else that was important.

Some interesting questions come to my mind. One question is whether the capacity of working memory can be increased. If the answer is yes, then I would like to know whether this might forestall or prevent losses in fluid intelligence as we age. If anyone knows of any relevant research on these issues I would appreciate your leaving a comment.

1Fukuda, K. Vogel, E., Mayr, U., & Awh, E. (2010). Quantity Not Quality: The Relationship Between Fluid Intelligence and Working Memory Capacity. Psychonomic Bulletin and Review, 17, 673-679.

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.