Development of the Episodic Memory from Toddler to Childhood
Memory plays an essential role in all human activities. It is a significant element in the formation and development of a personality, representing a direct link with the past and a collection of general knowledge. Therefore, the memory is one of the most substantial cognitive functions in human life. The professor at the University of Toronto, Tulving expressed the idea that there are two long-term memory systems: semantic and episodic. The latter is the only one that allows people to consciously recall past experiences and travel in time. The episodic memory is the first type of memorization, which children develop shortly after birth. It is an essential element of the self-protection system, and the process of world exploration. The episodic memory is formed in toddler years and continues to be developed until the middle childhood; it is the dominant memory type for children aged up to three years and an essential type for children from four years of age because it qualitatively affects the learning process and promotes semantic memory.
The Episodic Memory Research
The episodic memory is a memory system that consists of the event-driven information about the person in the multimodal form, which contains such relevant contextual features as time and place. The distinction between episodic memory (for personal events) and semantic memory (specific facts) was discovered by Tulving in 1972. It has been argued that episodic memory contains information related to the moments of the individual’s life, for example, studying at a college or the childhood experiences. On the other hand, semantic memory stores more than just abstract information, for example, it may contain the fundamental mathematical laws or basic theoretical aspects of psychology. It is proved that the same areas of the brain are responsible for episodic memories and for planning the future. Thus, memory and planning are closely linked and this gives a reason to believe that human past experiences provide sufficient knowledge required for the formation of thought-shaped structures for their future implementation. However, the Austrian scientists suggest that the transition from the knowledge search to episodic recall in children predetermines the success of experienced events but has detrimental effects on the indirect information.
Studies by American scientists have shown that the formation and development of episodic memory is dependent on a distributed network of brain areas, the hippocampus, and plays a crucial and irreplaceable role in this process. The experimental results confirmed the importance of the hippocampus functional connections among the different age groups that included lateral temporal regions, and multiple precuneus parietal and prefrontal areas, as well as functional specialization along the longitudinal axis.
Episodic and semantic memory types form declarative extended memory section, which includes such data as an intellectual encyclopedia. The first section communicates with another kind of the long-term memory, which is known as the procedural memory and a section with practical recommendations for the brain. Memories of abstract knowledge are stored in episodic context: after remembering some aspect of psychology, a person can mentally recreate the situation (season, mood, etc.), which was relevant for the studying process. In practice, this means that there is a distinction between two different types of memory for the facts and events that people typically use together. Evidences to support the distinctions are given by the results of the studies involving patients suffering from amnesia (temporary or permanent loss of memory). They usually keep most of the semantic recollections, but have poor episodic memory, being unable to remember conversations or the new people they have met.
The development of episodic memory is particularly relevant in childhood. This part of the human bio-system is deeply embedded in the foundations of human nature preventing people from potentially insecure decision-making. Thus, a man who once has gotten lost in a forest will be afraid to visit it alone to avoid the similar situation in the future. People are permanently involved in episodic experiences. However, kids provide astonishing examples of episodic studying in the process of discovering the initially strange world. For this reason, children acquire new knowledge and feelings, which contribute to the episodic memory.
Particular Qualities of the Toddler Episodic Memory
A toddler is a child from one to three years old. Infants of one year of age inherently have a clearly defined educational interest to the outside world in the process of cognitive development. In the interval between the very birth and the age of three years, the most pronounced features of early development of a child are expressed in the following: the rapid growth of the child mobility meaning that a kid starts to crawl and navigate through the place, exploring everything that comes in their way. A child also develops senses by interacting with various objects, flipping, throwing, and trying to grope and taste them. At this age, a kid is interested in books as attractive objects, rather than as the sources of information, carefully examining the images and flipping the pages. Thus, the formation of memory begins.
Children understand and learn more words and respond to requests. At this early age, they do not like to be alone, and are tempted by an opportunity to establish contact with an object with which they can interact. For this reason, the active development of the episodic memory, which forms a background for further semantic memory evolution, starts. Nevertheless, the formation of the conditioned reflex connections with all analyzers becomes possible during the fifth month of development. From that moment, a child recognizes bystanders and objects. It smiles and clasps hands at the sight of a mother, stretches and catches familiar items, which are not observed in the first months of life.
Initially hidden (latent) period of the recognition (i.e. the interval between the two perceptions, when admission is possible) is very short taking only a few days. In the second year of life, it increases to a few weeks, in the third one - up to several months, in four years - up to one year, and in seven years to about three years. Thus, the episodic memory is strengthening along with the increase of the term of memorization. Following the recognition, the first memories of the missing objects and faces appear. They are marked in children at the end of the first year of life in the most distinct form. When a kid at this age hears that someone mentions a familiar object, he or she starts visual search, turning the head and eyes to the side, where an object can usually be found.
With the transition to active self-speech (during the second or third year of life), the memories become more complete and specific as it is a means to secure the relations. The hidden play period gradually increases. In the second year of life, it is still limited to a few days, in the third – to a few weeks, and in the fourth – to a few months.
One of the reasons for the short duration of the recognition and playback latent periods in the early childhood is a lack of sufficiently strong link systems. These systems cannot accommodate the new conjunctions, thus, there is a small differentiation between the temporary connections. As a result, the vagueness and uncertainty of the first childhood memories can be observed, along with the rapid forgetting of the impressions received in early childhood. The core feature of the episodic memory is that kids aged two-three years remember only the events or objects of the current value at the particular moment because of their immediate vital needs and interests. Accordingly, a child can keep in mind only the things that render a strong emotional effect.
The Episodic Memory in Childhood
As a rule, some scattered memories of the early childhood refer to the fourth-fifth year of life only. In some cases, they are associated with very vivid emotional impact, and are related to an earlier age. More consistent and coherent memories of childhood usually occur at the age of five -seven years, sometimes even later - when a child is only nine years old.
Involuntary and episodic memory remains a leading type of memory in children of the pre-school age. Children address voluntary memory very seldom. Basically, it happens when a kid tries to settle certain tasks, or the adults demand it from a child in the daily activities. Involuntary memorizing of the information is associated with intellectual recollection of a certain material, and it remains leading to the end of pre-school age, which is free from infantile and childhood amnesia that is a state when a child forgets the earliest memories due to the natural development process. Thus, there is a fusion of episodic memory and semantic memories; it stands for a more harmonious accomplishment of these functions. In the course of experiments, New Zealand scientists have revealed that children at the turn of three-four years can save episodic memories, while the three year old kids do not possess this ability. The key feature of the cognitive development of a pre-school aged child is a new formation of functional system. Thus, memory as a core psychological process becomes the center of the child consciousness.
The pre-school age is characterized by the intensive development of the ability to memorize and reproduce information. Episodic memory is strengthened and evaluated. During this period, it has a spontaneous character. A kid does not try to set specific objectives for saving material and reproduce it in the future. Storing and recalling are carried out in the child’s activities. Kids remember only the interesting events and things.
A transition from involuntary to voluntary memory processes originates in the pre-school period. During this time, memory is aimed at remembering certain objects connected with the fact that a child tries to keep in mind and recall specific material. For this reason, the first manifestation of deliberate, voluntary memorization is observed in the middle pre-school age, during the fourth or fifth year of life only. It happens due to the significant development of the second signal system and strengthening of its role in the regulation of the child’s behavior.
Voluntary memory is closely connected with deliberate storage and replication of information that may occur if a child follows instructions or sets a task, especially if they are directly related to the primary children’s activity - a game. Therefore, pre-school children easily remember interesting songs, rhymes, and poems. Such material attracts a lot of interest associated with a game, which promotes deliberate memorization because it creates a strong emotional reinforcement for storing and reproducing the required actions. Studies have shown that deliberate memorization by the pre-school children of even a small number of words is much better revealed during a game (in gaming order) than when children try to remember them under artificial laboratory experiment.
A distinctive feature of the children’s memory is its visual-like character. A child learns the articles and pictures better, as well as the figurative and emotionally accompanied stories and descriptions from the verbal material. Abstract concepts and reasoning that could be hardly understood are not perceived by little children. Communicative skills of children are still insufficiently developed due to their limited experience of life; thus, memory relies mostly on the relationships between visually perceived objects. The prevalence of evident-shaped memory does not mean the lack of verbal and logical one. On the contrary, the latter develops rapidly, but its operation requires constant reinforcement from the direct (substantive) stimuli.
Intensive development of the episodic memory in childhood is associated with complex biological processes in the cerebral cortex. In the normally developing children, the episodic memory rapidly improves during the middle childhood. Binding hippocampus-dependent mechanisms are activated in early childhood, but improvements in the episodic memory continue due to the growth and development of the prefrontal cortex. Changes in the hippocampus, lateral development, parietal and prefrontal cortex evaluation, and white matter as a substance that connects brain areas are involved in the process as well. Thus, in the period of intensive growth of a child, the concerted efforts of a network of the brain related structures significantly influence the quality of episodic memory development.
Professor of psychology at the Ohio State University, Sloutsky admitted that for a long time it was believed that the formation of episodic memory is completed till the age of seven years. However, recent studies have shown that such type of memory continues to develop at a later age as well. An experiment conducted in conjunction with Yim, a doctoral student in psychology at Ohio State University, and Dennis of the University of Newcastle in Austral has proven that children under the age of seven years are very good at remembering specific events, but they may find it difficult to relate these memories with the context of the place and time they occurred. Children are experiencing serious difficulties with remembering events that have overlapping elements. Thus, it was concluded that some parts of the memory are almost completely developed until four years of age. However, some memory components are still evolving, even after a child reaches the age of seven.
Exercises to Improve the Episodic Memory in Children
The transition from infancy to early childhood is characterized by a special stage of the episodic memory development. It is strengthening in parallel with the semantic memory and requires constant training. The first type of exercises for the development of a conscious memory in children includes such domestic methods as a fairy tale. By telling a child different stories and repeating them, parents can observe the joyous reaction of a kid, who has learned a well-known episode. By telling and reading the familiar baby poems and tales, and pausing in some places, adults give a child an opportunity to remember and reproduce the parts that mother has forgotten. A kid will memorize words and phrases quickly. The same process occurs with toys. When naming toys, an adult needs to lay them around a child for a kid to find the right toy; over time, it will accurately identify where things are and remember their names. The core task of parents is to control the child activity in order not to allow a mechanical memorization, but rather to promote the achievement of a conscious result. A kid should clearly understand the meaning of each word and name.
The second type of exercises is connected with the enhanced physical activity. When taking a walk with a child, parents must tell him or her about the observed things, animals, and people. A kid should be able to sketch the observed objects after coming back home. Thus, this helps to develop and shape the episodic and verbal memories. Moreover, episodic memory is gradually transformed into a semantic.
Later, the plot of the read text drawing will be a useful exercise for the child’s memory development. Parents can propose a kid to study a story and read it no more than two times, observing the pictures. Then, it should be drawn or retold by a child. The audience could include the third persons - grandmother, sister, or even a favorite doll and a teddy bear.
The perfect memory training for the four-six-aged children is a well-known game with the disappearance of objects. Several items are put on the table, and a child is given time to remember them all before he or she is asked to leave. Several objects are removed, and when kid enters the room, he/she is asked to determine what things have disappeared.
It is significant to understand that the proper exercises to train children’s memory must not be carried out sporadically, as well as during any other classes. The more often and more regularly adults engage children in various activities, the faster and more efficiently they will learn new lessons. A child should never be forced to study; children themselves must be the initiators of educational games. Mutual understanding can be achieved only if a kid is encouraged to play by getting reward for each correctly completed task.
The research paper has shown that memory is a complex and substantial mechanism, which provides a background for becoming a full-fledged personality. The episodic memory is required as a system of receiving, processing, and storing the instantiated data. In children, it is characterized by shortness and forms a basis for the semantic memory development. The study has proven that the episodic memory evolution is directly dependent on the complex neurobiological processes in the cerebral cortex. A significant phase of this process occurs during childhood when the episodic memory is formed particularly rapidly. During this period, it gradually merges with semantic memory and operates with it as a single system. The training of episodic memory is necessary for children of any age. There are a lot of educational games and techniques that can ensure a harmonious and psychologically comfortable development of every child.