Memory development
The development of memory is a lifelong process that continues through adulthood. Development etymologically refers to a progressive unfolding. Memory development tends to focus on periods of infancy, toddlers, children, and adolescents, yet the developmental progression of memory in adults and older adults is also circumscribed under the umbrella of memory development.
The development of memory in children becomes evident within the first 3 years of a child's life as they show considerable advances in declarative memory, a child's memory throughout their development. This enhancement continues into adolescence with major developments in short term memory, working memory, long term memory and autobiographical memory.
The development of memory in adults, especially older adults, is often seen more negatively. Most adults will face symptoms of memory loss in both their short- and long-term memory; Alzheimer's is a prime example of this.
Recent research on the development of memory has indicated that declarative, or explicit memory, may exist in infants who are even younger than two years old. For example, newborns who are less than 3 days old demonstrate a preference for their mother's own voice, demonstrating the significance of a strong and powerful connection to the mother.
Cognitive neuroscience of memory development
develops very rapidly throughout the first 2 years of life; infants of this age show evidence of cognitive development in many ways. There is a difference in the brain development of explicit and implicit memory in infants. Implicit memory is controlled by an early-developing memory system in the brain that is present very early on, and can be explained by the early maturation of striatum, cerebellum, and brain stem, which are all involved in implicit learning and memory.Development of explicit memory depends on a later developing memory system in the brain that reaches maturity between 8 and 10 months of age. Explicit memory depends heavily on structures in the medial temporal lobe, including the hippocampus and the parahippocampal cortex. Much of the brain system is formed before birth, however the dentate gyrus within the hippocampal formation has about 70% of the number of cells in adults.
Rapid myelination of axons within the central nervous system occurs during first year of life which can dramatically increase the efficiency and speed of transmission in neurons. This can explain the higher processing speed of older infants as compared to younger ones.
Working memory
According to Baddeley's model of working memory, working memory is composed of three parts. First is the central executive which is responsible for a range of regulatory functions including attention, the control of action, and problem solving. Second, the phonological loop, which is specialized for the manipulation and retention of material in particular informational domains. Finally, the visuospatial sketchpad stores material in terms of its visual or spatial features. The strength of the relationships between the three components of working memory vary; the central executive is strongly linked with both the phonological loop as well as the visuospatial sketchpad which are both independent of each other. Some evidence indicates linear increases in performance of working memory from age 3–4 years through to adolescence.Central executive
Central executive is an integral of the working memory, and involves the all- inclusive attentional control of the working memory system. Initially Professor in Psychology Robert V. Kail and Professor Meghan Saweikis inferred that the central executive had an important role of storing some information and that the central executive reinforced long-term memory and has the potential to designate resources for focusing, dividing and switching attention. Currently the model of the central executive excludes the possibility of any type of memory storage. However, it does include the understanding that it does have a responsibility for the control and reinforcement of attention. In children from 2–4, the memory storage capacity limitation constrains complex comprehension processes. As the child grows older however, less processing is necessary which opens more storage space for memory.Phonological loop
Evidence indicates linear increases in performance from age 4 years through to adolescence. Prior to about 7 years of age, serial recall performance is mediated by the phonological store which is one of two components of the phonological loop. Preschool aged children do not use a subvocal rehearsal strategy to maintain decaying phonological representations in the store but instead they identify visual features of pictures in order to remember them. This is evident first by watching children for overt sign of rehearsal and second if the child is given nameable pictures, there are no differences in retrieval found for long versus short words. At the age of seven, children begin to use a subvocal rehearsal process to maximize retention in the phonological store. As development continues, nonauditory memory material is recoded into a phonological code suitable for the phonological loop when possible.Visuospatial sketchpad
Younger children may be more dependent than older children or adults on using the visuospatial sketchpad to support immediate memory for visual material. Older children adopt a strategy of verbally recoding pictures where possible and also use the phonological loop to mediate performance of the "visual" memory task. Between the ages of 5 and 11, visual memory span increases substantially and it is at this point when adult levels of performance are reached.Episodic buffer
The episodic buffer is something that was added to Baddeley' s working model in memory in the year 2000. It is believed to act as a connector of various sources within the memory process. The episodic buffer is a developing concept that is being researched and refined.In his initial paper, Professor of Psychology Alan Baddeley detailed what he believes to be the biological functioning, location, and purpose of the episodic buffer. The purpose of the episodic buffer is to serve as a bridge between both Working memory and Long-Term-Memory, specifically Episodic Memory. It is believed to be more temporary in its storage capabilities, but nonetheless helps form new information and lasting memory. Since it combines several elements of memory, one could in theory say it is a distributed system. The limits of its abilities in storage have yet to be determined. Other issues include identifying the differences between the Episodic Buffer and Episodic Memory, as well as showing how important and essential the Episodic Buffer is to the Working Model of Memory.
Long-term memory
Long-term memory, also known as episodic and semantic memory, has the ability to store valuable information for a proficient amount of time. According to Longe the storage of long-term memory could be in assortments of minutes to lifetime, meaning an activity or event attended can be recalled after a few minutes or be stored for a long time. Long term memory uses an important distinguishing factor known as meaning that can help an individual learn; It is used in a form of encoding and it is deemed the primary method of developing long-term memory. Once meaning is understood and applied to information it can impact what one recalls.Explicit memory becomes much better over the developmental years. However, there are small effects of age on implicit memory, which could be because implicit memory involves more basic processes than declarative memory which would make it less affected by a child's developing cognitive skills and abilities.
Infants
A surprising finding was that within the same age group of 2 to 3 months, infants could also remember an event or memory that was forgotten over the years. The infant experienced this recollection by a certain factor that might have sparked that forgotten memory. These impressive findings were found by testing the kicking of infants. Researchers placed a mobile over the infant's crib and a ribbon that connects the infant's leg to the mobile. The infants demonstrated to the researchers that they were learning the connection between their kicking and the mobile's movement. Once the allotted time passed, the infant's leg was attached once more to the mobile. Two types of ideas were formed; supposing that the child could energetically start kicking, would lead to the assumption that the infant remembered the connection between the mobile's movement and the child's kicking. Now, if the infant's kicking gingerly become more energetic, that would presume that the infant is relearning the connection, which would suggest that the infant has forgotten the connection made.The study also indicated that the infant could remember the connection for up to 14 days. However, once certain time has passed the infant's leg is once again connected to the mobile's movement with a ribbon to test of the infant recalled what to do. The infant did not remember what to do, and they were introduced to a certain factor that would aid the infant to remember. According to Professor Robert V. Kail and Professor Meghan Saweikis, if the experimenter moves the mobile showing the infant the movements, as soon as the infant is reconnected to the mobile with a ribbon, the infant will start kicking energetically. The conclusion was that the infant could indeed remember a memory, although time has passed.
Infants who are 5 months or older are able to use emotions to influence their memories. However, at this age, infants will be more likely to remember things that were characterized by positive emotions. Numerous mechanisms that are used to study and infer memory in children cannot be used on infants, due to the process the study is retrieved, which include writing or speaking. The way that researchers study the memory capabilities of infants in this age range is through measuring eye movements between test images presented. After doing this initial round of testing, the researchers would conduct follow-up tests both 5 minutes later and one day later. The follow-up tests shown to the infants included two geometric shapes: one from the original test, and a new shape. The researchers were able to record how long the infants looked at the images in the follow-up tests and measured how long the infants stared at each shape. The infants were more likely to gaze at the geometric shapes from the original tests if they had been paired with positive voices than if they had been paired with neutral or negative voices. This study indicated that infants at this age would be able to better remember shapes and patterns of things if they were associated with positive emotions because positivity would increase the infants' interest and attention.