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Lifespan Development of Memory

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Lifespan Development of Memory
Hello everyone, hello and welcome to the penultimate lecture of the course introduction to advanced cognitive processes I am Ark Verma from IIT Kanpur and in this week we have been talking about various aspects of cognitive development. Now I have talked about in this week already about biological factors that are responsible for human development, emotional development,motor development, we have talked at length about cognitive development.We have also talked in some sense about you know slightly complicated processes like the theory of mind and development of moral judgment etcetera. Now in this penultimate lecture of the week, I actually wanted to take one of the aspects of cognitive development separately and talk about it in terms of how it develops across the lifetime of an individual.The approach that I will be using to talk today is a referred to as the lifespan development of memory. So, I am I will be talking about this lifespan approach to development which argues that developmental change is continue beyond the young adulthood and people keep changing and adapting through their entire lives.Now the lifespan approach to development can be contrasted with you know typical notionsabout development where it is believed that the entire physical and cognitive maturationof the individual kind of you know culminates and you know reaches it is peak around theyoung adulthood time and they are not majors or significant changes that are going to comeafter that age onwards . In contrast the lifespan approach to the development of any aspect of human development and we are talking about memory today is the fact that you track the changes that happen with respect to that particular ability that you are trying to you know work with and see how it changes across the lifetime of an individual.For example, we will talk today about how memory you know develops how the skills about memory develop from very young children from 3 days to few months old children to you knowsenile population to elderly people 60, 70, 75-year-old individuals and we will see what changes come in this component of memory? How do people adjust to the coming changes?What are the strategies they used to remember stuff? And how do they organize information?What are the other skills that might help people to really you know kind of keep track of their memory abilities? Let us move slightly further. So, earlier it was believed in psychologists believed that, infants around 4 months of age could not remember much could not remember anything for more than a very brief period of time.Now this finding could also be a result of the kind of testing methods that were availablethen because more recently developmental psychologists have come up with new ways to test the infantsability to memorize people and object and they have basically opine for the fact thataround 6 month old infants can actually create association between objects even though theyhave not really seen those objects presented before together at the same time.So, there are cases being made the research is suggesting that cognitive psychologists might have underestimated the, you know the level of skill that children would have with respect to memory you know at the given age. So, let us kind of move slightly further from there when you talk about memory when you talk about say for example, what are the things that the child would you know need how would the child attend to learning and acquiring new information. So, attention patterns basically is a very important component, the thing that the child pays attention to if you remember I was talking to you about this a little bit when I when we were discussing about language acquisition.The child has to pay you know a lot of attention to whatever speech stimuli are going aroundthe child whatever in donations are being used with what kind of emotional expressionsomebody's speaking whatever sentence and where the child is doing is the child is payingattention to all of these signals even though it is not really understanding it in one senseof the word , but the fact is that the child is a very attentive listener and the childis processing all of this information. Similarly this attention that the child isapplying to his or her environment to whatever is being said or done around the child isvery important for the child to basically acquire or learn new material and it is inthat sense a very important aspect a very important ability that could contribute tosay for example, children's memory researchers have nowadays can measure infants memory bynoticing how long this spend paying attention to particular stimuli that is can be one ofthe ways if you remember we were talking about habituation and dishabituation when we aretalking about language acquisition. So, if the child is you know is getting familiarif the child recognizes his particular things then the child will not need to pay a lotof attention to that same thing again and again . So, this is one of the ways that researcherswho work with very young children infants for that matter use to infer whether the childhas acquired or remembered something or not. A very good demonstration of this one could be actually seen in Sangrigoli and de Schonens study where they wanted to test children for the own-race bias. Now own-race bias in memory is basically it refers to the tendency of people to recognize members of the same ethnic group more accurately in comparison to members of other ethnic groups. So, Caucasian children are given tasks to remember Caucasian faces to memorize Caucasian faces versus to memorize say for example,African American faces then you would see that generally, these children would probably you know recognize faces white children Caucasian children would recognize faces of Caucasian people slightly better then they would recognize the features of the African American people.Now, it is just an example the study in question here basically compared 3-month-old white babies Caucasian babies and they showed them pictures of white women and Asian women and the idea was they would present these pictures to the child repeatedly, again and again, till the amount of time that the child looked at the picture for reduces to almost half. This logic basically says that because now the child has memorized and the child knows that you know this is a familiar face. The child really does not want to spend much time on that, children are in some sense slightly miserly about how they you know going to use their resources. Now in this study researchers presented a pair of photos side by side there was one familiar photo and a photo of unfamiliar women from the same racial category. So, some testing was done they were made familiarize with some photos and then a familiar photo and an unfamiliar photo from either the same racial category or a different racial category could be presented .The results showed that babies who had initially seen a white woman and had gotten familiarize later looked longer at the unfamiliar white woman than at the familiar white woman. So,the idea is because they had been familiarize with this thing they are not really going to is take you know spend a lot of time looking at these pictures they are going to look slightly longer at the unfamiliar white women these data indicate that the babies could certainly tell the difference between familiar and unfamiliar white faces.Further babies were initially seen an Asian women remember we are talking about whitebabies, babies would seen and initially an Asian woman later looked equally at the familiarAsian women and the unfamiliar Asian woman, why is this happening because they are probablynot being able to memorize the features of the Asian face as well as they were able tomemorize the features of the white American face .So, that is basically the demonstration of that the fact that own-race bias exists, but it actually is more of you know more of a demonstration about that baby you know even at around 3 months of age and starts remembering faces. Let us talk about a different kind of memory again when we are talking about infants.So, recognizing mother research on visual recognition shows that even 3 day old infantscan distinguish their mothers face from a strangers face that is something slightlyremarkable also infants ability to recognize their mothers voice especially remarkable.Kisilevsky and colleagues in 2003 they tested infants about 1 or 2 weeks even before they were born. So, in the last couple of weeks of the pregnancy and they observed that the infant's heart rate changed more when hearing ah the mothers voice than when hearing an unfamiliar strangers voice. So, already you can see even before the child is born the child has acquired a degree of familiarity with the mothers voice as compared to the voice of somebody else . Now there is this a very interesting technique that people have used to kind of check whether children have memorized something or not.So, this one is referred to as the Conjugate Reinforcement technique.Now in the conjugate reinforcement technique what happens is that it is a mobile that hangs over our infant's crib and there is a ribbon that connects the infant's ankle and the mobile stand. So, the idea is whenever the infant is going to move for his or her feet the mobile is basically going to move you know there is going to be motion.Now after several minutes after this training is done after several minutes 2 to 6 monthold infants they start to kick rapidly and pump up the movement of the mobile and thenlie quietly and watch parts of the mobile move now I am not really referring to a mobilephone here I am referring to something that kind of moves over the cribs over the infantscrib. Now so, after several minutes 2 to 6 months old infants can begin to learn the fact they can begin to appreciate the fact that as soon as they kick the mobile starts to rotate. So, they will kick for a time once the movement is initiated they will kind of lay back and watch it is movement and that is there is a very interesting play idea as well. Now, they use this technique of conjugate reinforcement to assess the infants memory now what they do is they do all of the initial training in testing at the babies home in the babies own crib . So, that none of the reactions that the baby is going to make are basically because they are unfamiliar with the surroundings. Initially what they do is, they give a 3 minute period at the beginning of the first session the researcher kind of already takes a baseline measure how much that you know, how many movements or how many kicks the child is making anyways, during this time the ribbon is connected from the infant's angle to an empty mobile stand.So, there is just the stand there is nothing that is going to move and attract the child attention thus the experiment can now measure the amount of spontaneous kicks how much ever the child is kicking and the and they just note it down as a comparison to be made later. Now the experiment moves the ribbons and thenext thing the that this one does is that they can kind of measure the amount of spontaneouskick and then they be basically before the infant starts to move the mobile later whatthey do is and the moved the ribbon so that it turns runs from the babies angle to thestand in which now the mobile is hung. So, they kind of connect these 2 things the babies are allowed around 9 minutes to discover that when they kick it activates the movement of the mobile and this is basically refer to as the acquisition phase.So, now, the baby is learnt the fact and when I will kick the ribbon will actually let the mobile move, the infants basically receive these 2 training sessions typically around24 hours apart from each other at the end of the second session the ribbon is unhooked and returned to the empty stand for 3 minutes. Now again it is written and the mobile is moved and the ribbon is tie to the empty stand in order to measure whether the infants remember that they have to make this movement make this kicking movement to start the revolution. Researchers then measure long term memory after 1 to 42 days have elapsed, after the elapse time the mobile is hung again above the infant's crib with the ribbon hooked to the empty set. So, that is done if the infant recognizes the mobile and calls how kicking had produced movement then he or she would soon produce that foot kick response to make the mobile turn .Rovee - Collier who actually was doing this research devise an innovative way to checkwhether infants actually remembered how to activate the mobile, she also devised an objectivemethod for assessing the long term memory as she would now compare 2 measures they weretaking 2 measurements first was the number of kicks produced in the retention test withoutthe time being elapsed and the number of kicks after particular time has elapsed. So, they have 2 tests available. The later also devised a second operand conditioning task which is more appealing to infants slightly older 6 to 18 months old infants and in this task what was happening was the infants had to learn to press a particular level. So,that a trained you know a toy train could move around a circular track.Now they had these 2 tasks and they would compare the findings from these 2 tasks to trace infant memory from as early as 2 months to as late as 18 months of age .You can see here if you compare that mobile task and the train task you can see that 2to 6 month old infants already kick to act activate a mobile and 6 to 18 month old infantsthey press a lever to activate it you can see that the amount of retention that is aroundthe age of 6 months they would already retain this idea of kicking to produce a mobile movementfor around up to 2 weeks. Then you see that as the age in months increases the amount of retention goes from you know starting from 2 weeks to up to 13 weeks in the train tasks. So, this basically says the memory or the memory of the child in doing particular things is increasing and the amount of retention is increasing over time and itis almost a steady and linear improve during the first 18 months of life .Further Rovee - Collier and colleagues demonstrated that infants and adults memories has a veryyou know has quite a number of similarities, for example, infants also remembered betterwith distributed practice you give a a person you know an adult 18 years 20 or 25 year oldperson you give them a list to remember and ask them that you know you memorize this directlyall of this much in just this much lit this little time and come back and I will takea test. You will see that they perform rather poorly, but if you give them some material and you ask them to you know study it in separatebatches you study this for 1 hour take rest, then study this another material for 1 hourtake rest and study another material for 1 hour and take rest then if you take the youknow test of recall you will find that they have done better. Infants are also basically working like that they also remember better with distributed practice it is not really a great idea to make them learn everything at one go, infants show as well as adults the levels of processing effect. If you remember creek and I have talked about this in the course on mem, in the last course basic cognitive processes when we have talked about memory in much detail that in infants also there is a better recall for items that process at a deeper level, just to remind you shallower level is basically when you are just looking at the physical structure say, for example, the sound and you know the number etcetera. The deeper level is when the infant or when the child is started appreciating the meaning, started appreciating how to use that information that is a deeper level. So, if they process something to a deeper level they learn touse something they learn a skill for example, the kicking or the pressing lever thing they will remember it much better as compared to if it is just a you know information about how sound is like and those kind of things. Now let us talk about memory in children we have kind of moved slightly away from infants let us talk about slightly older children and you know memory is basically at least 2 major components working memory different components therein and long term memory . Now, let us talk about talks a little about working memory, memory spans basically improved dramatically during childhood according toa research evidence a 2 year old can recall about an average of 2 numbers in a row whereas,9 year olds can already recall around 6 numbers in a row. So, the yours think you think that the span of memory is increasing with age, children with high scores and phonological working memory a component of working memory are likely to excess in likely to excel in reading, writing and listening language-related tasks.Whereas, children who have a higher score on visual-spatial working memory the manipulation of information shapes and figures etcetera they are much likelier to excel in mathematics. So, you can see the relative contribution of the kinds of skills that the children will be good at and might lead to them being good in particular aspects of the studies .When you talk about long term memory children typically have excellent recognition memory,but they have a rather poor recall memory. In a test of recognition researchers presented2 and 4 year children with around 18 objects and they later presented a mix of 18 older objects that they had already presented and 18 newer objects what they find is that 2year olds recognition impressive 80 percent of the items whereas, 4-year-olds recognized about 90 per cent of the item. So, you see again there is this increase in recall with age. In another study Myers and Perlmutter they tested different groups of children for their ability to recall a set of 9 objects, the2-year-olds recalled only about 20 per cent of the items of the 20 per cent of the 9 objects whereas, the 4 years recalled around 40 per cent of the 9 objects it is you will see it is almost linear with age. Now a very important aspect of memory performance or even our memory performance or children's memory performance in general is, what are the strategies you are using to learn particular material that is a very very important aspect.So, memory strategies in that sense are very crucial to somebody's memory performance eventually.Memory strategies just to define it for you are intentional goal-oriented activities that we use to improve our memory suppose, for example, children and even adults for that matter they learn information with the goal of using it somewhere for children it is a performance in school tests, classes, etcetera for adults it might be to use somewhere to use it as an argument to use it to do something. Now young children do not always realize that strategies can be useful we do not appreciate the use and the kinds of strategies that might be available to them to you know learn a particular material better. Some children may not use these strategies effectively and this is a big problem this is referred to as the problem of utilization deficiency, they are not really bad at their memory the memory is not really bad, but you are not either aware of the strategies that can we use also they are not really using those strategies effectively and consistently .Older children; however, a typically realize that strategies are very useful in additionthey choose their strategies more carefully and use them consistently you can kind oflink it with the school performance, the school is getting tougher expectations to learn informationis there, there is this pressure to retain as much as possible children already startfiguring out ways of remembering and retaining information and in that process they startusing strategy start you know hit in trial use this strategy use that strategy and thenplan carefully that ok this one works best for me or this one works best for me. Older children also often use a variety of strategies so, they can kind of as I was saying the kind of choice between the number of strategies available to them .Now, the amount of information that you will remember also depends upon the kind of rehearsal that you are going to engage in . So, researchers suggest that 4 to 5 year olds do not really spontaneously rehearse material they want to remember. So, they do not really have this you know this idea of strategy. However, 7 year olds you know use they douse rehearsal strategies by the time they are 5 6 7 years old these do use strategiesand they often silently rehearse several words you know, by 7 year old you might at leastbe required to start remembering you know nursery rhymes and those kind of things andthis is where you will see that children are kind of you know repeating things mumblingthem in their mouth so, that they can recall this kind of information.Young children often benefit with the rehearsal strategies even though they do not use the strategy spontaneously they have to be instructed they have to be helped to start using these strategies, but once they use start using these strategies they do benefit from you know these strategies. There could be organizational strategies as well that might help the memory performance of individuals. Moely and colleagues in 1969they demonstrated in a study in which children studied you know they looked at pictures from4 categories, animals, clothing items, furniture and vehicles. During the 2 minutes study period,they were told that they could organize and rearrange these pictures in whichever way they wanted this arrangement could actually help them recall stuff better.If you remember in the memory chapter we talked about that if you start classifying things in categories you might be able to retain them better. But young children could really move the pictures next to each other you know they could not bring similar pictures together older children; however, appreciated the rule and they frequently organized the pictures into these different categories. Talking about imagery sometimes imagery is a good way to retain information if you remember how people would memorize cognitive maps orgeneral you know and how people would recognize you know paths or routes or you know layoutsof places use of imagery is very helpful for retaining information in memory; however,it is seen that it is not really research evidences or suggest that people use it so liberally. Spontaneous use of imagery does not even develop till until adolescence even though even most college students do not really use imagery as a strategy of10 enough to remember information. So, all in all as children develop they learn to use a variety of memory strategies in a more careful and consistent fashion and that already reflects in their memory performance. Now I will be talk to you a little bit about some applied aspects of children's memory. So, eyewitness testimony researchers have employed have implied that older children provide much more accurate eyewitness testimony than younger children, also research confirms that the accuracy of younger children's eyewitness testimony is often influenced by the choice age stereotyping and misleading suggestions.Now we have talked a little bit about children's memory aspects of children's memory, now let us move to the memory aspect of elderly people you know this is the lifespan development approach that we are following. So, I have kind of already given you a brief survey of what kind of memory abilities are there in children let us now survey briefly what are the memory abilities of elderly people . Stereotypes about elderly people often refer to them as being typically forgetful and all way and also cognitively incompetent at times,research on age-related changes in memory point through a picture that suggests larger individual differences and complex developmental trends in various components of memory.So, the picture is not really clear you cannot really definitively say that there is a significant decline in adults memory in elderly peoples memory unless you know they are suffering from a disease like Alzheimer's or dementia or those kind of things. People who are developing normally and you know they have no diseases and they have a significant degree of education research has shown that it does not really impact their memory so much.Let us talk about working memory research indicates that there are 8 similarities in performance and tasks that are relatively straightforward and require simple storage; however, age differences are observed in complicated tasks that require manipulation of information if you are you know if you are doing a working memory task say, for example, then back task you have to remember something that came on 2 trials back or 4 trials back or 6 trials back. Young and older adults perform similar a similarly on you know simpler tasks like digits pan asks that you know you just have to recall the numbers in serial order, but age difference are substantial on a working memory task where they have to keep some distracters away or perform 2 tasks simultaneously task switching kind of scenarios. Another example sign in colleague tested peoplesrecall for spoken English and the 2 condition, in one condition the sentences were spokenin and the correct orders normal syntax and at normal rate of speech here the performanceof adults and elderly people and young adults was the same, but when the there was you knowwhen the syntax was jumbled in the words were in jumbled order and they were being spokenat a faster rate the young adults performed much better than the elderly individuals .So, you can see that if the as the task gets more complex therein and there is where you can start seeing you know the difficulties in memory, talking about long term memory in elderly people. So, long term memory basically includes a few things it includes a semantic memory of how they are going to use memory etcetera .One of the aspects of long term memory is prospective memory that is remembering to do something in the future lists, to-do lists, you know go and do this and come back in these kinds of things. Older individuals generally have difficulty on many prospective memory tasks for example, in a task where individuals who are asked you know required to memorize a shopping list something that they would have to buy from you know marketplace later young in younger adults completed a greater number of tasks than the older adults.Implicit memory, implicit memory basically involves where there is no explicit recalling required. But you have to do a task that involves memory often the previously learned information. Now, Light and colleagues measured implicit memory in terms of the time that the participants required to read a letter sequence that was either familiar or unfamiliar, if they could read the letter sequence first it did kind of indicated memory. So, basically when they did this task adults between the ages of 64to 78 they performed relatively well as well as the younger adults who were between the ages of 18 to 24. On other research as well implicit memory shows either similar performances by adults and elder adults and younger adults or else just a slight deficit for the older adults. So, in tasks of implicit memory you see that there is almost no difference between how elderly people perform and how young people perform. Explicit recognition memory a number of research findings have converged on the fact that long term recognition memory their explicit recognition is required either declines slowly or not at all as people are doing older. So, 2 kindsof things are possible in one of the studies they did recognition memory task they foundthe 20 year olds correctly recognized around 67 percent of the words that had been presentedearlier and, but that 70 year olds recalled around 66 percent of the words so, there isalmost no decline here. But if you talk about this one was about explicit recognition memory this one is about explicit recall memory now explicit recall memory basically shows a lot of age differences the they are very marked age differences.In a study by Dunlosky and Hertzog when participants were asked to recall pairs of unrelated English words, 20-year-old participants recall an average of 20 percent more than the 70-year-old participants. However, elderly individuals also differedwidely in their performance on long term recall tasks for example, people who would have lowverbal ability and little education especially likely to show a decline, but people who havedecent education and they are ah you know having good for availability they can basicallyshow minimal age differences they kind of perform at par with a younger adult individualsthat was something I was saying in the beginning of the class.Now in summary if you yes again try and summarize the research on metamemory research on metamemory reveals that elder you know elderly adults and young adults are very similar in some respects when you know metamemory is concerned . So, this is all from me about the lifespandevelopmental approach to memory we talked about memory and differences of memory betweenyoung adults and old adults, infants as well and then we also talked about metacognitioncapability as metamemory thank you, I think this is the end of the course we will talkabout something more important in the next lecture.Thank you