How memory works

Individual differences

Humans have a long tradition of holding genes responsible for individual differences in behavior (of course, we called it "blood", then, or "family"). In the 20th century, a counter-belief arose: that it was all down to environment, to upbringing. In more recent decades, we have become increasingly aware of how tightly and complexly genes and environment are entwined.

It's not enough to say merely that environment tempers genes, or that genes affect how the environment works on an individual — genes and environment work on each other in an ongoing interaction, that continues throughout our lifetimes. This ongoing change even affects attributes most people deeply believe are, if not hard-wired in the womb, at least set in childhood: attributes such as intelligence, 'natural' talent, and gender differences.

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Right-Brain/Left-Brain

Are you right-brained or left-brained?

One of the dumber questions around.

I think it’s safe to say that if you only had one hemisphere of your brain, you wouldn’t be functioning.

Of course, that’s not the point. But the real point is little more sensible. The whole idea of right brain vs left brain did come out of scientific research, but as is so often the case, the myth that developed is light years away from the considerably duller scientific truths that spawned it.

It is true that, for most of us, language is processed predominantly in the left hemisphere. But what is becoming increasingly more evident is that even the most specialized tasks activate areas across the brain.

In any case, I don’t think the real meaning behind this simplistic dichotomy of right-brain / left-brain has much to do with the physical nature of the brain. People hope by rooting the concept in something that is physically real, that they will thereby make the concept real. Well, I’m sorry, but the supposed scientific foundation for the concept doesn’t exist. However, what we can ask is, is the concept valid? Are some people logical, analytical, sequential thinkers? Are others holistic, intuitive, creative thinkers?

Yes, of course. This is news?

But I don’t like dichotomies. It should never be forgotten that people aren’t either/or. Attributes invariably belong on a continuum, and we are all capable of responding in ways that differ as a function of the task we are confronted with, and the context in which it appears (especially, for example, the way something is phrased). Rather than saying a person is an analytical thinker, we should say, does a person tend to approach most problems in an analytical manner? This is not simply a matter of semantics; there’s an important distinction here.

But there are other personal attributes of importance in learning and problem-solving. For example, working memory capacity, imagery ability, anxiety level, extraversion / introversion, self-esteem (in this case, meaning assessment of one’s own abilities), field-dependence / field-independence (field dependence represents the tendency to perceive and adhere to an existing, externally imposed framework while field independence represents the tendency to restructure perceived information into a different framework). Which attributes are most important? Is this in fact a meaningful question?

The fact is, different personal attributes interact with different task and situational variables in different ways. While it’s probably always good to have a high working memory capacity (the capacity to hold more items in conscious memory at one time), it’s more important in some situations than others. To be a “high-imagery” person may sound a good thing, but if you realize it’s measured on a verbal-imagery continuum, you can see that it’s a trade-off. Personally, I’ve never found being high-verbal, low-imagery a drawback!

The point is, of course, that different styles lend themselves to different tasks (by which I mean, different ways of doing different tasks). It’s not so much what you are, as that you recognize what your strengths and weaknesses are, and realize, too, the pluses and minuses of those abilities / conditions.

For example, a study of 13-year olds investigated the question of interaction between working memory capacity and cognitive style, measured on two dimensions, Wholist-Analytic, and Verbaliser - Imager. They found working memory capacity made a marked difference for Analytics but had little effect for Wholists, and similarly, Verbalisers were affected but not Imagers [1].

Thus, if your working memory capacity is low, in demanding tasks you might find yourself better to approach it holistically – looking at the big picture, rather than focusing on the details.

Once you recognize your strengths and weaknesses, you can consciously apply strategies that work for you, and approach tasks in ways that are better for you. You can also work on your weaknesses. An interesting recent study that I believe has wider applicability than the elderly population who participated in it, found elderly people who draw on both sides of the brain seem to do better at some mental tasks than those who use just one side [2].

Web resources

Cognitive style

There’s an article about cognitive style from a business perspective:
http://www.elsinnet.org.uk/abstracts/aom/sad-aom.htm

If you’re really interested in cognitive style, the Wholist-Analytic, Verbal-Imager inventory was constructed by R.J. Riding, and he’s written a, fairly scholarly, book, entitled “Cognitive Styles and Learning Strategies: Understanding Style Differences in Learning and Behaviour”
http://tinyurl.com/6gpu8

Left-brain / Right-brain

You can also read an essay by William H. Calvin, an affiliate professor at the University of Washington School of Medicine in Seattle, Washington: Left Brain, Right Brain: Science or the New Phrenology?
http://williamcalvin.com/bk2/bk2ch10.htm

And an article first published in the New Scientist on 'Right Brain' or 'Left Brain' - Myth Or Reality? by John McCrone.
http://www.rense.com/general2/rb.htm

This article originally appeared in the January 2005 newsletter.

References: 

  1. Riding. R.J., Grimley, M., Dahraei, H. & Banner, G. 2003. Cognitive style, working memory and learning behaviour and attainment in school subjects. British Journal of Educational Psychology, 73 (2), 149–169.
  2. Cabeza, R., Anderson, N.D., Locantore, J.K. & McIntosh, A.R. 2002. Aging Gracefully: Compensatory Brain Activity in High-Performing Older Adults. NeuroImage, 17(3), 1394-1402.

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What is intelligence?

Intelligence in a cultural context

One theory of intelligence sees intelligence in terms of adaptiveness. Thus: "What constitutes intelligence depends upon what the situation demands" (Tuddenham 1963). Intelligence in these terms cannot be understood outside of its cultural context. Naturally to us it may seem self-evident that intelligence has to do with analytical and reasoning abilities, but we are perceiving with the sight our culture taught us.

If we lived, for example, in a vast desert, where success relied on your ability to find plants, water, prey and to remember these locations, an "intelligent" person would be one who was skilled at finding their way around and remembering what they'd seen and where they'd seen it. In a society where people are stuck within a limited social group, where people are forced to get on with each other because they can't escape each other, and where survival requires you to depend on these people, social skills will be highly valued. An "intelligent" person might well be a person who is skilled in social relations.

If I lived in such a society, would I have become skilled in these areas?

If I had spent my childhood playing with construction toys such as Lego, would I be better at spatial relations?

In other words, is intelligence something that you simply have in some measure, which manifests itself in the skills that you practice when young / that are valued in your society or within your family? Or are you born instead with particular talents that, if you are lucky, are valued by your society and thus seen as signs of intelligence?

Here's one of my favorite stories.

An anthropologist, Joe Glick, was studying a tribe in Africa1. The Kpelle tribe. Glick asked adults to sort items into categories. Rather than producing taxonomic categories (e.g. "fruit" for apple), they sorted into functional groups (e.g. "eat" for apple). Such functional grouping is something only very young children in our culture would do usually. Glick tried, and failed, to teach them to categorize items. Eventually he decided they simply didn't have the mental ability to categorize in this way. Then, as a last resort, he asked them how a stupid person would do this task. At this point, without any hesitation, they sorted the items into taxonomic categories!

They could do it, but in their culture, it was of no practical value. It was stupid.

Our IQ tests use categorization, and assumptions of how items relate to each other, to test "intelligence". (And how many of us, when filling in IQ tests, thought of different ways to answer questions, but answered the way we knew would be considered "right"?) These tests measure our ability to understand the mind of the test setter / marker. Do they measure anything else?

Multiple intelligences

One theory of intelligence that has had a certain influence on educational policy in the last 10-15 years is that of Howard Gardner’s idea of multiple intelligences (Gardner 1983). Gardner suggested that there are at least seven separate, relatively independent intelligences: linguistic, logical-mathematical, spatial, bodily kinaesthetic, intrapersonal, interpersonal, and musical.

Each intelligence has core components, such as sensitivity to the sounds, rhythms and meaning of words (linguistic), and has a developmental pattern relatively independent of the others. Gardner suggested the relative strengths of these seven intelligences are biologically determined, but the development of each intelligence depends on environmental influences, most particularly on the interaction of the child with adults.

This model of intelligence has positively influenced education most particularly by perceiving intelligence as much broader than the mathematical-language focus of modern education, and thus encouraging schools to spend more time on other areas of development.

It also, by seeing the development of particular intelligences as dependent on the child’s interaction with adults, encourages practices such as mentoring and apprenticeships, and supports parental and community involvement in educational environments. Because intelligence is seen as developing in a social context, grounding education in social institutions and in “real” environments takes on particular value.

All these are very positive aspects of the influence of this theory. On the downside, the idea of intelligence as being biologically determined is a potentially dangerous one. Gardner claims that a preschool child could be given simple tests that would demonstrate whether or not they had specific talents in any of those seven intelligences. The child could then be given training tailored to that talent.

Should we then deny that training to those who don't have that talent?

Do you know how many outstanding people - musicians, artists, mathematicians, writers, scientists, dancers, etc - showed signs of remarkable talent as very young children? Do you know how many so-called child prodigies went on to become outstanding in their field when adult? In both cases, not many.

The idea of "talent" is grounded in our society, but in truth, we have come no further in demonstrating its existence than the circular argument: he's good at that, therefore he has a talent for it; how do we know he has a talent? because he's good at it. Early ability does not demonstrate an innate talent unless the child has had no special opportunity to learn and practice the ability (and notwithstanding parental claims and retrospective reports, independent observation of this is lacking). (More on the question of innate talent)

Schooling and intelligence

The more we believe in innate talent, or innate intelligence, the less effort we will put into educating those who don't exhibit ability - although there are many environmental reasons for such failures.

The whole province of intelligence testing is, I believe, a dangerous one. Indeed, I was appalled to hear of its prevalence in American education. While intelligence was seen as some inborn talent unaffected by training or experience by the early makers and supporters of psychometric tests, recent research strongly suggests that schooling affects IQ score.

If you take two children who at age 13 have identical IQs and grades and then retest them five years later, after one child has finished high school while the other has dropped out of school in ninth grade, you find that the child who dropped out of school has lost around 1.8 IQ points for every year of missed school (Ceci, 1999).

Starting school late or leaving early results in a decrease in IQ relative to a matched peer who received more schooling. In families where children attend school intermittently, there is a high negative correlation between age and IQ, implying that as the children got older, their IQ dropped commensurately.

The most obvious, and simplest, explanation is that much of what is tested in IQ tests is either directly or indirectly taught in school. This is not to say schooling has any effect on intelligence itself (whatever that is).

References: 

  • Ceci, S. J. 1999. Schooling and intelligence. In S.J. Ceci & Wendy M. Williams (eds) The nature-nurture debate: The essential readings. Essential Readings in Developmental Psychology. Oxford: Blackwell. Pp168-175.
  • Ericsson, K.A. & Charness, N. Expert performance: Its structure and acquisition. In S.J. Ceci & Wendy M. Williams (eds) The nature-nurture debate: The essential readings. Essential Readings in Developmental Psychology. Oxford: Blackwell. Pp200-255.

1. Sternberg, R.J. 1997. Successful intelligence: How practical and creative intelligence determine your success in life. Plume.

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The question of innate talent

Some personal experience

I have two sons. One of them was a colicky baby. Night after night my partner would carry him around the room while I tried to get a little sleep. One night, for his own amusement, my partner chose a particular CD to play. Magic! As the haunting notes of the hymns of the 12th century abbess Hildegard of Bingen rang through the room, the baby stopped crying. And stayed stopped. As long as the music played. Experimentation revealed that our son particularly liked very early music (plainchant from the 15th century Josquin des Pres was another favorite).

We felt sorry for all those parents with crying babies who hadn't discovered this magic cure-all.

And then we had another son.

This one didn't like music. No magic this time. And we realized, it wasn't that 12th century music had magical properties to calm a crying baby. No, it was this particular baby that responded to this sort of music.

The years went on. Nothing we saw contradicted that first impression - one son was "musical", and one was not. It seemed pretty clear to us. One son took after me, and one took after my partner.

My partner plays the piano, and the pipe organ, and the harpsichord. He is "into" Bach. He has played in churches and concerts. He has a shelf full of books on music and cupboards full of music scores, CDs by the score.

Me? I like to sing, to myself. I learned the violin for a while in my youth. I like to listen to CDs of jazz, and popular show tunes. I like music, but I'm not sophisticated about it. It's background to me. My partner actually listens to it.

So which child took after which parent?

Well, we believe the "musical" one took after me, and the "non-musical" one took after my partner. Because - he got there by training. By practicing and learning and persevering and taking an interest. He has no sense of rhythm, no particularly keen sense of pitch. But he's the one who can produce music. Me, I have an ear for music. Remembering a rhythm is effortless for me; I respond, instinctively, to music. But I could never bother to practice, and my response to music has stayed at the same level. Instinctive.

Our "musical" son has been involved in learning music the Suzuki way since he was four. We never particularly encouraged our other son to do likewise, simply told him he could if he wanted to. His brother persuaded him he did want to. So, fine, we said.

You can guess, I'm sure, how things have been. It's been obvious, watching and listening to our older son, that he has a talent for music, that it comes easily to him. Equally obvious that it hasn't come that easily to our younger son. But it's the younger son who has made much faster progress in the past year, because he practices more, because he's keen to learn. And it's been amazing to watch his ear for music develop.

Do you need an inborn talent to do well?

Suzuki flew in the face of "common-sense" when he decided very young children with no demonstrable genius could be taught to play the violin. I can only imagine the stunned amazement with which the first Suzuki concerts were greeted. They still amaze today.

Suzuki himself, while he supported the training of all children, believed that, of course, some would be "naturally" gifted, and that outstanding performance would require a gift, as well as training. However, as his experience with children and his method increased, he grew to believe that “every child can be highly educated if he is given the proper training” and blamed early training failures on incorrect methods.

Howard Gardner (inventor of the Multiple Intelligences theory) reviewed the exceptional music performance attained by children trained in the Suzuki method, and noted many of these children, who displayed no previous signs of musical talent, attained levels comparable to music prodigies of earlier times. Therefore, he concluded, the important aspect of talent must be the potential for achievement and the capacity to rapidly learn material relevant to one of the intelligences. That is, since we didn't see the talent before we started training, and since the fact that they do perform so well demonstrates that they must have talent, then the talent must have existed in potential.

This is, of course, a wholly circular argument.

And one that is widely believed. According to an informal British survey, more than ¾ of music educators believe children can’t do well unless they have special innate gifts10. It is believed that saying that someone has a “gift” for something explains why they have excelled at something - although it is an entirely circular argument: Why do they do well? Because they have a gift. How do you know they have a gift? Because they do well.

It is also widely believed that such innate talents can be detected in early childhood.

The problem with this view is that many children are denied the opportunities and support to achieve excellence, because it has been decreed that they don’t “have” an appropriate talent.

The circular argument becomes truly a vicious circle. You don't do this easily first time, therefore you don't have any talent, therefore it's not worth pushing you to do well, therefore you won't do well - which proves what we told you in the first place, you have no talent!

So how much justification is there for believing excellence requires a "natural" talent?

Is there such a thing as inborn talent?

A questionnaire study found that early interest and delight in musical sounds fails to predict later musical competence25.

We have all heard stories of child prodigies who supposedly could do amazing things from a very young age. In no case however, is this very early explosion of skills (in the first three years) observed directly by an impartial observer – the accounts all being (naturally enough you might think), retrospective and anecdotal. Noone denies that very young children, from 3 years old, have been observed to have remarkable skills for their age, but although the parents typically say the child learned these skills entirely unaided, this is not supported by the evidence. For example, in a typical case, the parents claimed (and no doubt sincerely believed) that their child learned to read entirely unaided and that they only discovered this on seeing her reading Heidi. However they had kept detailed records of her accomplishments. As Fowler19 pointed out, it is difficult to believe that parents who keep such accounts have not been actively involved in the child’s early learning.

Music is an area where infant prodigies abound – many famous composers are reported to have displayed unusual musical ability at a very young age. Again, however, such accounts are reported many years later (after the composer has become famous). Early biographies of prominent composers reveal they all received intensive and regular supervised practice sessions29. “The emergence of unusual skills typically followed rather than preceded a period during which unusual opportunities were provided, often combined with a strong expectation that the child would do well."

Art is another area where infant "geniuses" are occasionally cited. However, although some 2 and 3 year olds have produced drawings considerably more realistic than is the norm45, among major artists, few are known to have produced drawings that display exceptional promise before age 8 or so44.

There is no doubt that some individuals acquire some skills more easily than others, but this doesn’t necessarily have anything to do with 'talent'. Motivational and personality factors, as well as previous learning experiences, can all affect such facility.

Biological factors that might underlie "talent"

There are various underlying factors that are at least partly genetic and no doubt influence ability – for example response speed2 and working memory capacity8,9 - but there is no clear neural correlate for any specific exceptional skill.

The closest such correlate is that of "perfect" pitch. There does appear to be a structural difference in the brain of those who have absolute pitch, and certainly some young children have been shown to have perfect pitch. However, even if this difference in the brain is innate and not, as it could well be, the result of differences in learning or experience, having perfect pitch is no guarantee that you will excel at music. Moreover, it appears that it can be learned. It’s relatively common in musicians given extensive musical training before five or six12, and even appears to be learnable by adults, although with considerably more difficulty3,42.

It is always difficult to demonstrate that an observed neurological or physical difference is innate rather than the product of training or experience. For example, many people have pointed to particular physical features as being the reason for particular sports people to excel at their particular sport. However, while individual differences in the composition of certain muscles are reliable predictors of differences in athletic performance, the differences in the proportion of the slow-twitch muscle fibres that are essential for success in long-distance running, for example, are largely the result of extended practice, rather than the cause of differential ability11. Differences between athletes and others in the proportions of particular kinds of muscle fibres are specific to those muscles that are most fully exercised in the athletes’ training22.

There is little evidence, too, for the idea that exceptional athletes are born with superior motor and perceptual abilities. Tests for basic motor and perceptual abilities fail to predict performance15. Exceptional sportspeople do not reliably score higher than lesser mortals on such basic tests.

Savants

So-called idiot-savants are widely cited in support of the idea of innate talent. However, studies of cases have found the opportunities, support and encouragement for learning the skill have preceded performance by years or even decades12,23,43. Moreover, their skills are learnable by others.

The only ability that can’t be reproduced after brief training is the reputed ability to reproduce a piece of music after a single hearing. However, in a study of one such savant5 it was shown that such reproduction depended on the familiarity of the sequences of notes. Tonally unconventional pieces were remembered poorly. Thus, musical savants, like normal experts, need access to stored patterns and retrieval structures to enable them to retain long, unfamiliar musical patterns.

Predicting adult performance

Several interview and biographical studies of exceptional people have been carried out (e.g., pianists40,41; musicians31; tennis players35; artists37; swimmers26; mathematicians20). In no case could you have predicted their eventual success from their early childhood behavior; few showed signs of exceptional promise prior to receiving parental encouragement.

Composers21, chess players36, mathematicians20, sportspeople26,32 have all been shown to require many years of sustained practice and training to reach high levels of expertise.

Twin studies

Twin studies support the view that family experience is more important than genes for the development of specific abilities (e.g., The Minnesota Study of Twins Reared Apart found self-ratings of musical talent correlated .44 among identical twins reared apart, compared to .69 for identical twins reared together30; correlations on a number of measures of musical ability were not much lower for fraternal twins (.34 to .83) than for identical twins (.44 to .9)7.

Moreover, the importance of inherited factors reduces as training and practice increases1,28,15.

Practice and performance level

The performance level of student violinists in their 20s is strongly correlated with the number of hours that they practiced13,14. Similarly with pianists27. No significant differences have been found between highly successful young musicians and other children in the amount of practice time they required to make a given amount of progress between successive grades in the British musical board exams; achieving the highest level (grade 8) required an average of some 3300 hours of practice regardless of the ability group to which the student had been assigned39. Another study found that by age 20, the top-level violinists had practiced an average of more than 10000 hrs, some 2500 hrs more than the next most accomplished group15.

Practice accounts for far more than most of us might realize. Several studies have demonstrated the high levels of performance (often higher than experts had regarded as possible) that can be attained by perfectly ordinary adults, given enough practice4,6,12.

It has been argued that talent encourages children to practice more, but this is contradicted by the finding that, even among highly successful young musicians, most admit they would never have regularly practiced at the required level without strong parental encouragement38,24.

The top of the cream?

It may well be, of course, that there is a quality to the exceptionally talented person’s performance that is missing from others, however hard they have practiced.

It is also possible that, although practice, training, and other influences may account for performance differences in most people, there is a small number of people to whom this doesn’t apply.

However, there is at this time no evidence that this is true.

What is clear is that “no case has been encountered of anyone reaching the highest levels of achievement in chess-playing, mathematics, music, or sports without devoting thousands of hours to serious training” (Howe et al 1999).

The pattern of learning seems to be the same for everyone, arguing against some qualitative difference between "geniuses" and ordinary folk. Studies of prodigies in chess and music show that the skills are acquired in the same manner by everyone, but that prodigies reach higher levels faster and younger16,17. Moreover, rather than acquiring their skills in a vacuum, it appears that “the more powerful and specific the gift, the more need for active, sustained and specialized intervention” (Feldman, 1986, p123).

The producing of an outstanding talent indeed, seems to require a great deal of parental support and early intervention.

It is particularly instructive to observe the case of the Polgar daughters. With no precocious love for the chess board observable in their three daughters, Laslo & Klara Polgar, simply as an educational experiment, decided to raise their daughters to be chess experts. All did extraordinarily well, and one became the youngest international chess grand master ever18.

It has been noted that the performance of experts of yesteryear is now attainable by many. When Tchaikovsky asked two of the greatest violinists of the day to play his violin concerto, it is said, they refused, deeming it unplayable33 - now it is standard repertoire for top violinists. Paganini, it is claimed, would cut a sorry figure on a concert stage today34. Such is the standard we have come to expect from our top performers.

And we are all familiar with the way sports records keep being broken – the winning time for the 1st Olympic marathon is now the qualifying time for the Boston marathon.

Are we suddenly breeding more talent?

No. But training has improved immeasurably.

Practicing effectively

It is not, then, simply practice that is important. It is the right practice. Ericsson & Charness distinguish between deliberate practice – which involves specifically tailored instruction and training, with feedback, and supervision - and the sort of playful repetition more characteristic of people who enjoy an activity and do it a lot. Most people reach an acceptable level of performance, and then are satisfied. The "talented" ... keep on.

References: 

  1. Ericsson, K.A. & Charness, N. Expert performance: Its structure and acquisition. In S.J. Ceci & Wendy M. Williams (eds) The nature-nurture debate: The essential readings. Essential Readings in Developmental Psychology. Oxford: Blackwell. Pp200-255.
  2. Howe, M.J.A., Davidson, J.W. & Sloboda, J.A. 1999. Innate talents: Reality of myth? In S.J. Ceci & Wendy M. Williams (eds) The nature-nurture debate: The essential readings. Essential Readings in Developmental Psychology. Oxford: Blackwell. Pp168-175.

Footnoted references

  1. Ackerman, P.L. 1988. Determinants of individual differences during skill acquisition: cognitive abilities and information processing. Journal of Experimental Psychology: General, 117, 299-318.
  2. Bouchard, T.J., Lykken, D.T., McGue, M., Segal, N.L. & Tellegen, A. 1990. Sources of human psychological differences: the Minnesota Study of Twins Reared Apart. Science, 250, 223-8.
  3. Brady, P.T. 1970. The genesis of absolute pitch. Journal of the Acoustical Society of America, 48, 883-7.
  4. Ceci, S.J., Baker, J.G. & Bronfenbrenner, U. 1988. Prospective remembering, temporal calibration, and context. In M. Gruneberg, P. Morris, & R. Sykes (eds). Practical aspects of memory: Current research and issues. Wiley.
  5. Charness N Clifton J & MacDonald L. 1988. Case study of a musical mono-savant. IN LK Obler & DA Fein (eds) The exceptional brain: Neuropsychology of talent and special abilities (pp277-93). NY: Guilford Press.
  6. Chase, W.G. & Ericsson, K.A. 1981. Skilled memory. In J.R. Anderson (ed). Cognitive skills and their acquisition. Erlbaum.
  7. Coon, H. & Carey, G. 1989. Genetic and environmental determinants of musical ability in twins. Behavior Genetics, 19, 183-93.
  8. Dark, V.J. & Benbow, C.P. 1990. Enhanced problem translation and short-term memory: components of mathematical talent. Journal of Educational Psychology, 82, 420-9.
  9. Dark, V.J. & Benbow, C.P. 1991. The differential enhancement of working memory with mathematical versus verbal precocity. Journal of Educational Psychology, 83, 48-60.
  10. Davis, M. 1994. Folk music psychology. Psychologist, 7, 537.
  11. Ericsson, K.A. 1990. Peak performance and age: an examination of peak performance in sports. In P.B. Baltes & & M.M. Baltes (eds). Successful aging: Perspectives from the Behavioral Sciences. Cambridge University Press.
  12. Ericsson, K.A. & Faivre, I.A. 1988. What's exceptional about exceptional abilities? In K. Obler & D. Fein (eds). The exceptional brain. Guilford Press.
  13. Ericsson, K.A., Tesch-Romer, C. & Krampe, R. Th. 1990. The role of practice and motivation in the acquisition of expert-level performance in real life. In M.J.A. Howe (ed). Encouraging the development of exceptional abilities and talents. British Psychological Society.
  14. Ericsson, K.A., Krampe, R.Th. & Heizmann, S. 1993. Can we create gifted people? In G.R. Bock & K. Ackrill (eds). The origins and development of high ability. CIBA Foundation Symposium, 178. Wiley.
  15. Ericsson, K.A., Krampe, R.Th. & Tesch-Romer, C. 1993. The role of deliberate practice in the acquisition of expert performance. Psychological Review, 100, 363-406.
  16. Feldman, D.H. 1980. Beyond universals in cognitive development. Norwood, NJ: Ablex.
  17. Feldman, D.H. 1986. Nature's gambit: Child prodigies and the development of human potential. NY: Basic Books.
  18. Forbes, C. 1992. The Polgar sisters: Training or genius? NY: Henry Holt.
  19. Fowler, W. 1981. Case studies of cognitive precocity: the role of exogenous and endogenous stimulation in early mental development. Journal of Applied Developmental Psychology, 2, 319-67.
  20. Gustin, W.C. 1985. The development of exceptional research mathematicians. In B.S. Bloom (ed). Developing talent in young people. Ballantine.
  21. Hayes, J.R. 1981. The complete problem solver. Franklin Institute Press.
  22. Howald, H. 1982. Training-induced morphological and functional changes in skeletal muscle. International Journal of Sports Medicine, 3, 1-12.
  23. Howe, M.J.A. 1990. The origins of exceptional abilities. Oxford, UK: Blackwell.
  24. Howe, M.J.A. & Sloboda, J.A. 1991. Young musicians' accounts of significant influences in their early lives: 2. Teachers, practising and performing. British Journal of Music Education, 8, 53-63.
  25. Howe, M.J.A., Davidson, J.W., Moore, D.G. & Sloboda, J.A. 1995. Are there early childhood signs of musical ability? Psychology of Music, 23, 162-76.
  26. Kalinowski, A.G. 1985. The development of Olympic swimmers. In B.S. Bloom (ed). Developing talent in young people. Ballantine.
  27. Krampe, R.Th. 1994. Maintaining excellence: cognitive-motor performance in pianists differing in age and skill level. Max-Planck-Institut fur Bildungsforschung.
  28. Krampe, R.Th. & Ericsson, K.A. 1996. Maintaining excellence: cognitive-motor performance in pianists differing in age and skill level. Journal of Experimental Psychology: General, 125, 331-68.
  29. Lehmann, A.C. 1997. The acquisition of expertise in music: efficiency of deliberate practice as a moderating variable in accounting for sub-expert performance. In J.A. Sloboda & I. Deliege (eds). Perception and cognition of music. Erlbaum.
  30. Lykken, D. 1998. The genetics of genius. In A. Steptoe (ed). Genius and the mind. Oxford University Press.
  31. Manturzewska, M. 1986. Musical talent in the light of biographical research. In Musikalische Begabung Finden und Forden, Bosse.
  32. Monsaas, J. 1985. Learning to be a world-class tennis player. In B.S. Bloom (ed). Developing talent in young people. Ballantine.
  33. Platt, R. 1966. General introduction. In J.E. Meade & A.S. Parkes (eds). Genetic and environmental factors in human ability. Edinburgh: Oliver & Boyd.
  34. Roth H 1982 . Master violinists in performance. Neptune City, NJ: Paganinia
  35. Schneider, W. 1993. Acquiring expertise: determinants of exceptional performance. In K.A. Heller, F.J. Monks & A.H. Passow (eds). International Handbook of Research and Development of Giftedness and Talent. Pergamon.
  36. Simon, H.A. & Chase, W.D. 1973. Skill in chess. American Scientist, 61, 394-403.
  37. Sloan, K.D. & Sosniak, L.A. 1985. The development of accomplished sculptors. In B.S. Bloom (ed). Developing talent in young people. Ballantine.
  38. Sloboda, J.A. & Howe, M.J.A. 1991. Biographical precursors of musical excellence: an interview study. Psychology of Music, 19, 3-21.
  39. Sloboda, J.A., Davidson, J.W., Howe, M.J.A. & Moore, D.G. 1996. The role of practice in the development of performing musicians. British Journal of Psychology, 87, 287-309.
  40. Sosniak, L.A. 1985. Learning to be a concert pianist. In B.S. Bloom (ed). Developing talent in young people. Ballantine.
  41. Sosniak, L.A. 1990. The tortoise, the hare, and the development of talent. In M.J.A. Howe (ed). Encouraging the development of exceptional abilities and talents. British Psychological Society.
  42. Takeuchi, A.H. & Hulse, S.H. 1993. Absolute pitch. Psychological Bulletin, 113, 345-61.
  43. Treffert DA 1989 Extraordinary people: Understanding “Idiot Savants”. NY: Harper & Row.
  44. Winner, E. & Martino, G. 1993. Giftedness in the visual arts and music. In K.A. Heller, F.J. Monks & A.H. Passow (eds). International Handbook of Research and Development of Giftedness and Talent. Pergamon.
  45. Winner, E. 1996. The rage to master: the decisive role of talent in the visual arts. In K.A. Ericsson (ed). The road to excellence: The acquisition of expert performance in the arts and sciences. Erlbaum.

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The role of emotion in memory

Does emotion help us remember? That's not an easy question to answer, which is unsurprising when you consider the complexities of emotion.

First of all, there are two, quite different, elements to this question. The first concerns the emotional content of the information you want to remember. The second concerns the effect of your emotional state on your learning and remembering.

The effect of emotional content

It does seem clear that, as a general rule, we remember emotionally charged events better than boring ones.

Latest research suggests that it is the emotions aroused, not the personal significance of the event, that makes such events easier to remember.

The memory of strongly emotional images and events may be at the expense of other information. Thus, you may be less likely to remember information if it is followed by something that is strongly emotional. This effect appears to be stronger for women.

It does seem that memories are treated differently depending on whether they are associated with pleasant emotions or unpleasant ones, and that this general rule appears to be affected by age and other individual factors. Specifically, pleasant emotions appear to fade more slowly from our memory than unpleasant emotions, but among those with mild depression, unpleasant and pleasant emotions tend to fade evenly, while older adults seem to regulate their emotions better than younger people, and may encode less information that is negative.

An investigation of autobiographical memories found that positive memories contained more sensorial and contextual details than neutral or negative memories (which didn't significantly differ from each other in this regard). This was true regardless of individual's personal coping styles.

  • Emotionally charged events are remembered better
  • Pleasant emotions are usually remembered better than unpleasant ones
  • Positive memories contain more contextual details (which in turn, helps memory)
  • Strong emotion can impair memory for less emotional events and information experienced at the same time
  • It's the emotional arousal, not the importance of the information, that helps memory

The effect of mood

Another aspect of emotion is mood - your emotional state at the time of encoding or retrieving. There has been quite a lot of research on the effect of mood on memory. It is clear that mood affects what is noticed and encoded. This is reflected in two (similar but subtly different) effects:

  • mood congruence: whereby we remember events that match our current mood (thus, when we're depressed, we tend to remember negative events), and
  • mood dependence: which refers to the fact that remembering is easier when your mood at retrieval matches your mood at encoding (thus, your chances of remembering an event or fact are greater if you evoke the emotional state you were in at the time of experiencing the event or learning the fact).

An interesting issue in the study of emotion is the degree to which what we feel is influenced by our expression of it. In other words, does a person who conceals what they are feeling feel as deeply as a person who openly displays their emotion? Does the expression of emotion, in itself, affect what we feel?

I remember reading Paul Ekman (the guru of interpreting facial expressions, and author of several books on the subject) say that, when practicing the expressions, he found himself experiencing the emotions they expressed. However, accurate expression of emotion does seem to require considerable expertise (if the emotion is not, in fact, being felt) - people are very good at distinguishing false expressions of emotion.

The way people go about controlling their reactions to emotional events does seem to affect their memory of the event. People shown a video of an emotional event and instructed not to let their emotions show were found to have a poorer memory for what was said and done than did those who were given no such instructions.

However, as with emotional content, we cannot simply say that emotional state affects memory. The nature of the emotion being felt is also important. And this, too, is not straightforward. We cannot simply say, for example, that anxiety impairs memory and happiness improves it.

A small study in which participants performed difficult cognitive tasks after watching short videos designed to elicit one of three emotional states ( pleasant, neutral or anxious), found that mild anxiety improved performance on some tasks, but hurt performance on others. Similarly, being in a pleasant mood boosted some kinds of performance but impaired other kinds.

This may have something to do with different emotions being involved with different brain regions.

  • Remembering is easier when your mood matches the mood you were in when experiencing/learning the information
  • The stronger the emotions aroused, the greater the effect on memory
  • Emotions can be evoked, or minimized, by displaying or suppressing expressions of emotion
  • Different emotional states may impair or help memory, for different memory tasks

Brain regions involved in the emotion-memory interaction

The brain region most strongly implicated in emotional memory is the amygdala. The amygdala is critically involved in calculating the emotional significance of events, and, through its connection to brain regions dealing with sensory experiences, also appears to be responsible for the influence of emotion on perception - alerting us to notice emotionally significant events even when we're not paying attention. The amygdala appears to be particularly keyed to negative experiences.

But it is not only the amygdala that is involved in this complex interaction. The cerebellum, most strongly associated with motor coordination skills, may also be involved in remembering strong emotions, in particular, in the consolidation of long-term memories of fear.

Parts of the prefrontal cortex also appear to be involved. One study found that a region of the prefrontal cortex was jointly influenced by a combination of mood state and cognitive task, but not by either one alone. Another study found that the dorsolateral prefrontal cortex is more active when the participants were surprised by unexpected responses.

Is surprise an emotion? I think surprise is right there in the fuzzy border between two related phenomena - emotion and attention. Interestingly, our understanding of these two phenomena is about on a par - still woefully inadequate (but greatly improving!).

The relationship between emotion and attention

Research suggests that emotional stimuli and "attentional functions" move in parallel streams through the brain before being integrated in a specific part of the brain's prefrontal cortex (the anterior cingulate). This is why emotional stimuli are more likely than simple distractions to interfere with your concentration on a task such as driving.

We now think that attention is not, as has been thought, a global process, but consists of at least three distinct processes, each located in different parts of the frontal lobes. These are:

  1. a system that helps us maintain a general state of readiness to respond;
  2. a system that sets our threshold for responding to an external stimulus; and
  3. a system that helps us selectively attend to appropriate stimuli.

Correspondingly, emotional arousal helps us maintain a "readiness to respond", and also has a selective effect on the particular stimuli we notice and encode. Perhaps, indeed, attention may be thought of as a state of activity that is triggered by various kinds of emotional arousal, and modulated by such arousal.

How do emotions affect memory?

Well, we're still foggy on details, but there appear to be two main aspects to this. One is that stress hormones, such as cortisol, interact with the amygdala. The other is that the amygdala can alter the activity of other brain regions. One of the ways in which it does this is by acting on consolidation processes (principally in the hippocampus).

It is perhaps this effect on consolidation that is reflected in a study using facial stimuli (involving inversion of eyes and mouth to change the emotional impact of a face without significantly changing its visual features), that indicated that the emotional load of a stimulus does not in fact affect the way we perceive it but does have an effect on how we become used to it if we see it many times.

Notwithstanding this study, however, it does seem clear that, in some circumstances and for some types of stimuli, at least, the emotional attributes of a stimulus do affect the way we perceive it and process it - that is, the encoding of the memory.

One of the ways in which it might do this is through the involvement of different brain regions depending on the nature of the emotion experienced. A recent imaging study found that positive emotional contexts evoked activity in the right fusiform gyrus (among other regions), and negative emotional contexts evoked activity in the right amygdala.

Another way in which emotions might affect memory encoding is through working memory. It has been suggested that, in the case of anxiety, part of working memory may be taken up with our awareness of fears and worries, leaving less capacity available for processing. In support of this theory, one study found that math-anxious people have working memory problems as they do math.

Age and gender differences

It also seems that there are differences in the way men and women process emotional memories. Women are better at remembering emotional memories. They also seem to be more likely to forget information presented immediately before emotionally charged information. This suggests that women are more affected by emotional content - a suggestion compatible with the finding that women and men tend to encode emotional experiences in different parts of the brain. In women, it seems that evaluation of emotional experience and encoding of the memory is much more tightly integrated.

There is also an age difference. The tendency to let unpleasant memories fade faster than pleasant ones gets stronger as we age. This is perhaps a reflection of older people's apparent ability to regulate their emotions more effectively than younger people, by maintaining positive feelings and lowering negative feelings. Preliminary brain research suggests that in older adults, the amygdala is activated equally to positive and negative images, whereas in younger adults, it is activated more to negative images. It may be that older adults encode less information about negative images.

It has also been speculated that age-related cognitive decline may be partly caused by a greater cortisol responsivity to stress.

  • The key player in the processing of emotional memories appears to be the amygdala
  • Other brain regions, in particular the prefrontal cortex and the cerebellum, are also involved
  • While these regions are important for all, men and women do show differences in the parts of the brain they use to encode emotion
  • Emotion and attention are related phenomena
  • Emotion acts on memory at all points of the memory cycle - at encoding, consolidation, and retrieval
  • Emotion acts on memory in various ways, including the production of stress hormones, use of working memory capacity, and involvement of particular brain regions

 

References: 

  • Anderson, A.K. & Phelps, E.A. 2001. Lesions of the human amygdala impair enhanced perception of emotionally salient events. Nature, 411, 305-309.
  • Canli, T., Desmond, J.E., Zhao, Z. & Gabrieli, J.D.E. 2002. Sex differences in the neural basis of emotional memories. Proceedings of the National Academy of Sciences, 99, 10789-10794.
  • Charles, S.T., Mather, M. & Carstensen, L.L. 2003. Aging and Emotional Memory: The Forgettable Nature of Negative Images for Older Adults. Journal of Experimental Psychology: General, 132(2), 310-24.
  • D'Argembeau, A., Comblain, C. & Van der Linden, M. 2002. Phenomenal characteristics of autobiographical memories for positive, negative, and neutral events. Applied Cognitive Psychology, 17(3), 281-94.
  • Erk, S. et al. 2003. Emotional context modulates subsequent memory effect. Neuroimage, 18, 439-447.
  • Fletcher, P.C., Anderson, J.M., Shanks, D.R., Honey, R., Carpenter, T.A., Donovan, T., Papadakis, N. & Bullmore, E.T. 2001. Responses of human frontal cortex to surprising events are predicted by formal associative learning theory. Nature Neuroscience, 4, 1043-1048.
  • Gray, J.R., Braver, T.S. & Raichle, M.E. Integration of emotion and cognition in the lateral prefrontal cortex. Proceedings of the National Academy of Sciences, 99, 4115-4120.
  • Hamann, S. 2001. Cognitive and neural mechanisms of emotional memory. Trends in Cognitive Sciences, 5 (9), 394-400.
  • Lewis, P.A. & Critchley, H.D. 2003. Mood-dependent memory. Trends in Cognitive Sciences, 7 (9).
  • Lupien, S.J., Gaudreau, S., Tchiteya, B.M., Maheu, F., Sharma, S., Nair, N.P.V., Hauger, R.L., McEwen, B.S. & Meaney, M.J. 1997. Stress-Induced Declarative Memory Impairment in Healthy Elderly Subjects: Relationship to Cortisol Reactivity. The Journal of Clinical Endocrinology & Metabolism, 82 (7), 2070-2075.
  • Nielson, K.A., Yee, D. & Erickson, K.I. 2002. Modulation of memory storage processes by post-training emotional arousal from a semantically unrelated source. Paper presented at the Society for Neuroscience annual meeting in Orlando, Florida, 4 November.
  • Nijholt, I., Farchi, N., Kye, M-J., Sklan, E.H., Shoham, S., Verbeure, B., Owen, D., Hochner, B., Spiess, J., Soreq, H. & Blank, T. 2003. Stress-induced alternative splicing of acetylcholinesterase results in enhanced fear memory and long-term potentiation. Molecular Psychiatry advance online publication, 28 October 2003.
  • Richards, J.M. & Gross, J.J. (2000). Emotion Regulation and Memory: The Cognitive Costs of Keeping One's Cool. Journal of Personality and Social Psychology, 79 (3), 410-424.
  • Richeson, J. & Shelton, N. 2003. When Prejudice Does Not Pay: Effects of Interracial Contact on Executive Function. Psychological Science, 14(3).
  • Sacchetti, B., Baldi, E., Lorenzini, C.A. & Bucherelli, C. 2002. Cerebellar role in fear-conditioning consolidation. Proc. Natl. Acad. Sci. U.S.A., 99 (12), 8406-8411.
  • Strange, B.A., Hurleman, R. & Dolan, R.J. In press. An emotion-induced retrograde amnesia in humans is amygdala and b-adrenergic dependent. Proceedings of the National Academy of Sciences.
  • Stuss, D.T., Binns, M.A., Murphy, K.J. & Alexander, M.P. 2002. Dissociations Within the Anterior Attentional System: Effects of Task Complexity and Irrelevant Information on Reaction-Time Speed and Accuracy. Neuropsychology, 16 (4), 500–513.
  • Walker, W.R., Skowronski, J.J. & Thompson, C.P. 2003. Life Is Pleasant -- and Memory Helps to Keep It That Way! Review of General Psychology, 7(2),203-10.
  • Yamasaki, H., LaBar, K.S. & McCarthy, G. Dissociable prefrontal brain systems for attention and emotion. Proc. Natl. Acad. Sci. USA, 99(17), 11447-51.

 

For more, see the research reports

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Identity memory

Recognizing a person is a complex matter.

There are several different types of memory code for identity information. These include:

  • structural codes
  • semantic codes
  • visually-derived semantic codes
  • name codes

The interesting thing about these different memory codes is that it appears that they can only be accessed in a particular order. This is part of the reason names are so much harder to recall - they're at the end of the chain.

Improving your memory for people requires you to improve the connections between these memory codes.

Difficulty in remembering people’s names is one of the most common memory tasks that people wish to be better at. And the reason for this is not that their memory is poor, but because it is so embarrassing when their memory lets them down.

This isn’t just an issue at a personal level. It’s a particular issue for anyone who has to deal with a lot of people, many of whom they will see at infrequent intervals. Nothing makes a person — a client, a customer, a student — feel more valued than being remembered.

But we have, in fact, a remarkably good memory for other people’s faces. Think about the ease with which you distinguish between hundreds, even thousands, of human faces, and then think about how hard it is to distinguish between the faces of birds, or dogs, or monkeys. This is not because human faces are any more distinctive than the faces of other animals. Think about how much harder it is for you to distinguish between the faces of people of an unfamiliar racial type.

Contrary to what many European-descended people believe, Asian faces are no less distinctive than European faces, but the differences between any human face are sufficiently subtle that they take a great deal of experience to learn. The importance of learning these subtle differences is shown in the way new babies focus on faces, and prefer them to other objects.

Our memory for other people is of course more than a memory for faces, although that part probably has the most impressive capacity. We also remember people’s names and various biographical details. We can recognize people by hearing their voice, at a distance by seeing their shape or the way that they move, or even by their clothing.

But it’s faces that give certainty.

Many years ago, when I was in my second year at university, I left the student cafeteria and nearly bumped into a young woman in a white lab coat. I murmured some sort of apology and started to move on, and she said my name. I stared at her blankly. She said, ‘You don’t recognize me, do you?’ Even with this prompt, I didn’t immediately get it. I still remember staring at her unfamiliar face, and then … the features seemed to shift under my eyes. It was very weird. Suddenly I knew her. I was mortified, and stunned. I hadn’t seen her in a year, but we’d been best friends all through high school. How could I not immediately recognize her?

Identity information is complex

Identity information is encoded in memory in quite complex ways. To more effectively use those codes, to improve your memory for names, faces, and important personal details, it helps to understand how identity information is recorded in memory.

There are three ways we can “recognize” a person:

  • we might recognize them as having been seen before, without recalling anything about them
  • we might identify them as a particular person, without recalling their name (“that’s a friend of my son’s”)
  • we might identify them by name

If you think about it you will realize that you never, ever, recall information about a person without recognizing them as familiar. While this sounds terribly obvious, there is actually a clinical condition (the Capgras delusion) whereby a person, while recognizing the people around them, believes they have been replaced by doubles (imposters, robots, aliens). This is simply because the normal accompanying feeling of familiarity is missing.

You also never remember a person’s name without knowing who she is. This is because names are held in a separate place to biographical details, and can only be accessed through those details.

Identity codes and how they are structured in memory

Why is there this hierarchy? Why can we only access names through biographical information? Because identity information is ordered. Your memory for a person is not like this:

diagram

But like this:

diagram

In other words, there are several different kinds of identity information, and they are clustered according to type, and can in fact only be accessed in a particular order.

Of the various identity codes (bits of encoded identity information), there are three kinds that are important for recognizing a person:

  • structural codes (physical features)
  • semantic codes (biographical details, e.g., occupation, marital status, address)
  • name codes

There is a fourth type of code that is useful for remembering unfamiliar faces:

  • visually-derived semantic codes (e.g., age, gender, attributions such as “he looks honest/intelligent/sly”)

Semantic codes that are visually derived have an advantage over biographical codes, because the link with the structural code is meaningful and thus strong, whereas the connection between the structural codes and biographical details is entirely arbitrary. To say someone looks like a fox connects meaningfully with the person’s facial features, whereas to say that someone is a lawyer has no particular connection with the person’s face (to say someone looks like a lawyer would of course be meaningfully connected).

Visually-derived semantic codes are useful for remembering new faces because the link with the physical features of the face is strong and meaningful.

However you cannot identify a person without reference to the biographical codes.

The interesting aspect of these different codes is that you can only access them in a particular order:

diagram

When you recognize a face as familiar but can’t recall anything about the person, the physical features have failed to trigger the biographical details. When you identify a person by recalling details about them, but can’t recall their name, the biographical information has failed to trigger the name.

Whether the name is recalled therefore depends on the strength of the connection between the biographical details and the name.

In other words, to improve your memory for a person’s identity, you must strengthen the link between the physical features and the biographical information. To improve your memory for the person’s name, you must strengthen the link between the biographical information and the name.

 

Note: A fascinating account of what it is like to be face-blind, from a person with the condition, can be found at: http://www.choisser.com/faceblind/

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Working memory

Working memory is one of the most important concepts in understanding and improving your memory.

Your working memory capacity is a critical factor in determining your ability to :

  • take good notes,
  • read efficiently,
  • understand complex issues,
  • reason.

Indeed it may be that it is your working memory capacity that best ‘measures’ your intelligence.

Short-term vs long-term memory

Working memory is a relatively recent term, a refinement of an older concept - that of short-term memory. Short-term memory was called thus to distinguish it from "long-term memory" - your memory store.

One important difference between the idea of short-term memory and working memory, is that short-term memory was conceived of as a thing. Different from long-term memory (variously analogized as a library, a filing system, a computer) chiefly in the duration of the records it held. But working memory, as its name suggests, is now conceived more as a process than a thing. A state of mind. A pattern of activation.

Working memory contains the information of which you are immediately aware.

To put information into our memory store, it must ... be worked on - i.e., be held in working memory. To get information out of the memory store - to “remember” something - it must again be in an active state - be in working memory. How can we know what we remember if we're not conscious of it?

However, you can only keep something "active" for a very short time without your conscious attention. It is this which so limits working memory capacity.

The magic number seven

Probably the most widely known fact about working memory is that it can only hold around seven chunks of information (between 5 and 9). However, this tells us little about the limits of working memory because the size of a chunk is indeterminate.

1 2 3 4 5 6 7 are seven different chunks - if you remember each digit separately (as you would, for example, if you were not familiar with the digits - as a young child isn't). But for those of us who are only too well-versed in our numbers, 1 through to 7 could be a single chunk.

Recent research suggests however, that it is not so much the number of chunks that is important. What may be important may be how long it takes you to say the words (information is usually held in working memory in the form of an acoustic - sound-based - code). It appears that you can only hold in working memory what you can say in 1.5 — 2 seconds. Slow speakers are therefore penalized.

Your working memory capacity

What we term "working memory" contains several functions, including the "central executive" which coordinates and manages the various tasks needed. The extent to which working memory is domain-specific (different "working memories", if you like, for different sensory and cognitive systems, such as language, spatial memory, number) is still very much debated. However, at a practical level, we may think of working memory as containing several different components, for which you have different "capacities". Thus, your capacity for numbers may well be quite different from your capacity for words, and both from your capacity for visual images.

References: 

For more, see the research reports

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Why we mix up names of people we know well

  • A large survey sheds light on why we have slips of the tongue when we call very familiar people by the wrong name.

We've all done it: used the wrong name when we know the right one perfectly well. And we all know when it's most likely to happen. But here's a study come to reassure us that it's okay, this is just how we roll.

The study, based on five separate surveys of more than 1,700 respondents, finds that these naming errors (when you call someone you know very well by the wrong name) follow a particular pattern that tells us something about how our memory is organized.

Usually the wrong name comes from the same relationship category. So I call one son by the name of the other; on a bad day (e.g. when there's a lot going on, perhaps a lot of people around, and I'm thinking of many other things — say, at Christmas), I might run through both sons, my partner, and my father!

Not just family, you can mix up friends' names too. And the bit that's really enlightening: family members might also be called by the name of the family dog! Interestingly, only the dog; cat owners don't make such slips of the tongue. (Yes, dogs are family; cats not so much.)

Unsurprisingly, phonetic similarity between names is also a factor, although it's less important than relational category. Names with the same beginning or ending sounds, or with shared phonemes (e.g., John and Bob), are more likely to be muddled.

But it's not affected by physical similarity between people — not even by gender (which surprised me, but then, in my household I'm the only female).

More importantly, it's not a function of age. Misnaming errors are common across the board.

http://www.futurity.org/moms-families-dogs-names-1152392/

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Individuals vary in how they remember events

  • Individuals vary in how vividly they remember the past. A new study links this to differences in brain activity which may reflect a stable trait.
  • The finding also has implications for assessments of age-related cognitive decline.

A study involving 66 healthy young adults (average age 24) has revealed that different individuals have distinct brain connectivity patterns that are associated with different ways of experiencing and remembering the past.

The participants completed an online questionnaire on how well they remember autobiographical events and facts, then had their brains scanned. Brain scans found that those with richly-detailed autobiographical memories had higher mediotemporal lobe connectivity to regions at the back of the brain involved in visual perception, whereas those tending to recall the past in a factual manner showed higher mediotemporal lobe connectivity to prefrontal regions involved in organization and reasoning.

The finding supports the idea that those with superior autobiographical memory have a greater ability or tendency to reinstate rich images and perceptual details, and that this appears to be a stable personality trait.

The finding also raises interesting questions about age-related cognitive decline. Many people first recognize cognitive decline in their increasing difficulty retrieving the details of events. But this may be something that is far more obvious and significant to people who are used to retrieving richly-detailed memories. Those who rely on a factual approach may be less susceptible.

http://www.eurekalert.org/pub_releases/2015-12/bcfg-wiy121015.php

Full text available at http://www.sciencedirect.com/science/article/pii/S0010945215003834

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Memory capacity of brain 10 times more than thought

  • New measurements have exploded the previous estimates of the human brain's memory capacity, and also help explain how neurons have such computational power when their energy use is so low.

The question of the brain's capacity usually brings up remarks that the human brain contains about 100 billion neurons. If each one has, say, 1,000 or more connections to other neurons, this produces some 100 trillion connections in which our memory can be held. These connections are between synapses, which change in strength and size when activated. These changes are a critical part of the memory code. In fact, synaptic strength is analogous to the 1s and 0s that computers use to encode information.

But, here's the thing: unlike the binary code of computers, there are more than two sizes available to synapses. On the basis of the not-very-precise tools researchers had available, they had come up with three sizes: small, medium and large. They also had calculated that the difference between the smallest and largest was a factor of 60.

Here is where the new work comes in, because new techniques have enabled researchers to now see that synapses have far more options open to them. Synapses can, it seems, vary by as little as 8%, creating a possible 26 different sizes available, which corresponds to storing 4.7 bits of information at each synapse, as opposed to one or two.

Despite the precision that this 8% speaks to, hippocampal synapses are notoriously unreliable, with signals typically activating the next neuron only 10-20% of the time. But this seeming unreliability is a feature not a bug. It means a single spike isn't going to do the job; what's needed is a stable change in synaptic strength, which comes from repeated and averaged inputs. Synapses are constantly adjusting, averaging out their success and failure rates over time.

The researchers calculate that, for the smallest synapses, about 1,500 events cause a change in their size/ability (20 minutes), while for the largest synapses, only a couple hundred signaling events (1 to 2 minutes) cause a change. In other words, every 2 to 20 minutes, your synapses are going up or down to the next size, in response to the signals they're receiving.

Based on this new information, the new estimate is that the brain can hold at least a petabyte of information, about as much as the World Wide Web currently holds. This is ten times more than previously estimated.

At the moment, only hippocampal neurons have been investigated. More work is needed to determine whether the same is true across the brain.

In the meantime, the work has given us a better notion of how memories are encoded in the brain, increased the potential capacity of the human brain, and offers a new way of thinking about information networks that may enable engineers to build better, more energy-efficient, computers.

http://www.eurekalert.org/pub_releases/2016-01/si-mco012016.php

http://www.scientificamerican.com/article/new-estimate-boosts-the-human-brain-s-memory-capacity-10-fold/

Full text at http://elifesciences.org/content/4/e10778v2

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