Introduction to cognitive development

Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, language learning, and other aspects of brain development and cognitive psychology compared to an adult's point of view. In other words, cognitive development is the emergence of the ability to think and understand. A large portion of research has gone into understanding how a child imagines the world. Jean Piaget was a major force in the discovering of this field study, forming his "theory of cognitive development". Piaget had four stages of cognitive development which consisted of the following : Sensorimotor, preoperational,concrete operational and formal operational. Many of his theoretical claims have since fallen out of favor. However, his description of the tendencies of cognitive development (e.g., that it moves from being dependent on actions and perception in infancy to understanding of the more observable aspects of reality in childhood to capturing the underlying abstract rules and principles in adolescence) is generally still accepted today. Besides, many of the phenomena that he discovered, such as object permanence in infancy and the conservations in school age children, attract the interest of current researchers. In recent years, alternative models have been advanced, including the neo-Piagetian theories of cognitive development, which aim to integrate Piaget's ideas that stood the test of time with more recent theorizing and methods in developmental and cognitive science.

A major controversy in cognitive development has been "nature vs. nurture", or nativism versus empiricism. However, it is now recognized by most experts that this is a false dichotomy: there is overwhelming evidence from biological and behavioral sciences that from the earliest points in development, gene activity interacts with events and experiences in the environment. Another issue is how culture and social experience relate to developmental changes in thinking. Another question is phylogenic convergence or homology with non-human animals. Most aspects of learning and cognition are similar in humans and non-human animals, and the question of behavioral homology has been of interest to cognitive developmentalists from both evolutionary and developmental points of view. These issues propagate to nearly every aspect of cognitive development.

Speculated core systems of cognition
Empiricists study how these skills may be learned in such a short time. The debate is over whether these systems are learned by general-purpose learning devices, or domain-specific cognition. Moreover, many modern cognitive developmental psychologists, recognizing that the term "innate" does not square with modern knowledge about epigenesis, neurobiological development, or learning, favor a non-nativist framework. Researchers who discuss "core systems" often speculate about differences in thinking and learning between proposed domains. Researchers who posit a set of so-called "core domains" suggest that children are innate sensitivity to specific kinds of patterns of information. Those commonly cited include:

Number
Infants appear to have two systems for dealing with numbers. One deals with small numbers, often called subitizing. Another deals with larger numbers in an approximate fashion.

Space
Very young children appear to have some skill in navigation. This basic ability to infer the direction and distance of unseen locations develops in ways that are not entirely clear. However, there is some evidence that it involves the development of complex language skills between 3 and 5 years. Also, there is evidence that this skill depends importantly on visual experience, because congenitally blind individuals have been found to have impaired abilities to infer new paths between familiar locations.

Later in life, adults can use language and symbols (e.g., maps) to reason about information. When an adult's ability to process languages is engaged in other tasks, they reason in different ways.

Visual perception
One of the original nativist versus empiricist debates was over depth perception. There is some evidence that children less than 72 hours old can perceive such complex things as biological motion. However, it is unclear how visual experience in the first few days contributes to this perception. There are far more elaborate aspects of visual perception that develop during infancy and beyond. [elaboration of this section is forthcoming!]

Essentialism
Young children seem to be predisposed to think of biological entities (e.g., animals and plants) in an essentialistic way. This means that they expect such entities (as opposed to, e.g., artifacts) to have many traits such as internal properties that are caused by some "essence" (such as, in our modern Western conceptual framework, the genome).

Language acquisition
A major, well-studied process and consequence of cognitive development is language acquisition. The traditional view was that this is the result of deterministic, human-specific genetic structures and processes. Other traditions, however, have emphasized the role of social experience in language learning. However, the relation of gene activity, experience, and language development is now recognized as incredibly complex and difficult to specify. Language development is sometimes separated into learning of phonology, morphology, syntax, semantics, and discourse or pragmatics. However, all of these aspects of language knowledge—which were originally posited by the linguist Noam Chomsky to be autonomous or separate—are now recognized to interact in complex ways.

Piaget’s theory of cognitive development
Jean Piaget (1896-1980) believed that people move through stages of development that allow them to think in new, more complex ways.

Sensorimotor stage

 * The first stage in Piaget’s Stages of Cognitive Development is the sensorimotor stage. This stage lasts from birth to two years old. During this stage, behaviors lack a sense of thought and logic. Behaviors gradually move from acting upon inherited reflexes to interacting with the environment with a goal in mind and being able to represent the external world at the end.
 * The sensorimotor stage has been broken down into six sub stages that explain the gradual development of infants at this age.
 * Birth to one month
 * Each child is born with inherited reflexes that they use to gain knowledge and understanding about their environment. Examples of these reflexes include grasping and sucking.
 * 1–4 months
 * Children repeat behaviors that happen unexpectedly because of their reflexes.
 * For example, a child’s finger comes in contact with the mouth and the child starts sucking on it. If the sensation is pleasurable to the child, then the child will attempt to recreate the behavior. Infants use their initial reflexes (grasping and sucking) to explore their environment and create schemes. Schemes are groups of similar actions or thoughts that are used repeatedly in response to the environment. Once a child begins to create schemes they use accommodation and assimilation to become progressively adapted to the world. Assimilation is when a child responds to a new event in a way that is consistent with an existing schema. For example, an infant may assimilate a new teddy bear into their putting things in their mouth scheme and use their reflexes to make the teddy bear go into their mouth. Accommodation is when a child either modifies an existing scheme or forms an entirely new schema to deal with a new object or event. For example, an infant may have to open his or her mouth wider than usual to accommodate the teddy bear's paw.
 * 5–8 months
 * Child has an experience with an external stimulus that they find pleasurable, so they try to recreate that experience. For example, a child accidentally hits the mobile above the crib and likes to watch it spin. When it stops the child begins to grab at the object to make it spin again.In this stage habits are formed from general schemes that the infant has created but there is not yet, from the child’s point of view, any differentiation between means and ends. Children cannot also focus on multiple tasks at once, and only focus on the task at hand. The child may create a habit of spinning the mobile in its crib, but they are still trying to find out methods to reach the mobile in order to get it to spin in the way that they find pleasurable. Once there is another distraction (say the parent walks in the room) the baby will no longer focus on the mobile. Toys should be given to infants that respond to a child’s actions to help foster their investigative instincts. For example, a toy plays a song when you push one button, and then a picture pops up if you push another button.
 * 8–12 months
 * Behaviors will be displayed for a reason rather than by chance. They begin to understand that one action can cause a reaction. They also begin to understand object permanence, which is the realization that objects continue to exist when removed form view. For example: The baby wants a rattle but the blanket is in the way. The baby moves the blanket to get the rattle.  Now that the infant can understand that they object still exists, they can differentiate between the object, and the experience of the object. According to psychologist David Elkind, “An internal representation of the absent object is the earliest manifestation of the symbolic function which develops gradually during the second year of life whose activities dominate the next stage of mental growth."
 * 12–18 months
 * Actions occur deliberately with some variation.For example a baby drums on a pot with a wooden spoon, then drums on the floor, then on the table.
 * 18 - 24 months
 * Children begin to build mental symbols and start to participate in pretend play. For example, a child is mixing ingredients together but doesn't have a spoon so they pretend to use one or use another object the replace the spoon Symbolic thought is a representation of objects and events as mental entities or symbols which helps foster cognitive development and the formation of imagination. According to Piaget, the infant begins to act upon intelligence rather than habit at this point. The end product is established after the infant has pursued for the appropriate means. The means are formed from the schemes that are known by the child. The child is starting to learn how to use what it has learned in the first two years to develop and further explore their environment.


 * These six sub-stages represent the approximate growth a child undergoes during Piaget’s sensorimotor stage from birth to age 2. Once the child gains the ability to mentally represent reality, the child begins the transition to the preoperational stage of development.

Preoperational stage
Lasts from 2 years of age until 6 or 7. It can be characterized in two somewhat different ways. In his early work, before he had developed his structuralist theory of cognition, Piaget described the child’s thought during this period as being governed by principles such as egocentrism, animism and other similar constructs. Egocentrism is when a child can only see a certain situation his or her own way. One can not comprehend that other people have other views and perceptions of scenarios. Animism is when an individual gives a lifeless object human like qualities. An individual usually believes that this object has human emotions, thoughts and intentions. Once he had proposed his structuralist theory, Piaget characterized the preoperational child as lacking the cognitive structures possessed by the concrete operational child. The absence of these structures explains, in part, the behaviors Piaget had previously described as egocentric and animistic, for example an inability to comprehend that another individual may have different emotional responses to similar experiences.

Concrete operational stage
Lasts from 6 or 7 years until about 12 or 13. During this stage the child’s cognitive structures can be characterized by group therapy. Piaget argues that the same general principles can be discerned in a wide range of behaviors. One of the best-known achievements of this stage is that of conservation. In a typical conservation experiment a child is asked to judge whether or not two quantities are the same – such as two equal quantities of liquid in a short and tall glass. A preoperational child will typically judge the taller, thinner glass to contain more, while a concrete operational child will judge the amounts still to be the same. The ability to reason in this way reflects the development of a principle of conservation.

Formal operational stage
This final stage begins at ages 12 or 13. It marks a movement from an ability to think and reason from concrete visible events to an ability to think hypothetically; to entertain what-if possibilities about the world. Children at this stage develop abstract-thinking. They can solve problems systematically by using abstract concepts. The cognitive structures of this stage can be characterized by four rules for manipulating the content of thought: identity, negation, reciprocity, and correlativity.

Criticism
Many of his claims have fallen out of favor. For example, he claimed that young children cannot conserve number. However, further experiments show that children did not really understand what was being asked of them. When the experiment is done with candies, and the children are asked which set they want rather than tell an adult which is more, they show no confusion about which group has more items.

Whorf's hypothesis
Benjamin Whorf, while working as a student of Edward Sapir, posited that a person's thinking depends on the structure and content of their social group's language. In other words, it is the belief that language determines our thoughts and perceptions. For example, it used to be thought that Greeks, who wrote left to right, thought differently than Egyptians since the Egyptians wrote right to left. Whorf’s theory was so strict that he believed if a word is absent in a language, then the individual is unaware of the object’s existence. This theory was played out in George Orwell’s book, Animal Farm; the pig leaders slowly eliminated words from the citizen’s vocabulary so that they were incapable of realizing what they were missing. The Whorfian hypothesis failed to recognize that people can still be aware of the concept or item, even though they lack efficient coding to quickly identify the target information.

Quine's bootstrapping hypothesis
Willard Van Orman Quine (1908-2000) suggested that there are innate conceptual biases that determine the language meaning that we acquire, and the concepts and beliefs that we acquire, as we develop. Quine's theory relates to other nativist philosophical traditions, such as the European rationalist philosophers. A relevant figure in this nativist tradition for cognitive developmental theory is Immanuel Kant.

Neuroscience and Cognitive Development
During development, especially the first few years of life, children show interesting patterns of neural development and a high degree of neuroplasticity. The relation of brain development and cognitive development is extremely complex and, since the 1990s, has been a growing area of research.

Cultural influences
From cultural psychologists’ view, minds and culture shape each other. In other words, culture can influence brain structures which then influence our interpretation of the culture. These examples reveal cultural variations in neural responses:

Figure-Line Task (Hedden et al., 2008)

Behavioral research has shown that one’s strength in independent or interdependent tasks differ based on their cultural context. In general, East Asian cultures are more interdependent whereas Western cultures are more independent. Hedden et al. assessed functional magnetic resonance imaging (fMRI) responses of East Asians and Americans while they performed independent (absolute) or interdependent (relative) tasks. The study showed that participants used regions of the brain associated with attentional control when they had to perform culturally incongruent tasks. In other words, different neural paths used for the same task were different for Americans and East Asians (Hedden et al., 2008).

Kobayashi et al., 2007

Kobayashi et al. compared American-English monolingual and Japanese-English bilingual children’s brain responses in understanding others’ intentions through false-belief story and cartoon tasks. They found universal activation of the region bilateral ventromedial prefrontal cortex in Theory of Mind tasks. However, American children showed greater activity in the left inferior frontal gyrus during the tasks whereas Japanese children had greater activity in right inferior frontal gyrus during the Japanese Theory of Mind tasks. In conclusion, these examples suggest that the brain’s neural activities are not universal but are culture dependent.

Concepts
Concepts are the fundamental agents of intellectual work. Concepts are viewed as the distillate of sensory experience and the vital link between external inputs and overt behaviors.

Mental Construct
Concepts as mental constructs are the critical component of a maturing individual’s continuously changing, enlarging cognitive structure. When considered from a learning point of view over short time periods, a person’s concepts provide the basis for interpreting and organizing incoming information and also for forming principles and other complex relations among concepts. Maturing individuals attain concepts according to their unique informal and formal learning experiences and their maturational patterns. The word concept not only designates mental constructs of individuals but also the meanings of words and other symbols accepted by social groups who speak the same language.

Concrete – abstract concepts
A means of classifying concepts is in terms of whether the defining attributes can be perceived. Concrete concepts have perceptible attributes; they can be physically seen or proven. Examples are animal, or color. Concrete concepts are usually easier for a child to understand. Abstract concepts are those whose attributes cannot be directly perceived, such as imagination. Abstract ideas are something that are more difficult for children to understand. For example, explaining death to a child can be difficult because it is hard to change it into a concrete concept.

Concepts and Words
The term ‘word’ is usually used to refer to the meaningful basic elements of a language. Words can be spoken or written. When they are written the boundaries of a word are clear because words are separated from each other by spaces. When words are spoken the boundaries are less clearly marked – we must draw on our knowledge of the language to segment the speech we hear into meaningful units. That this is not a trivial task is evident if a comparison is made between the tasks of counting the number of words written in a language we do not understand and counting the number of words spoken in the same language. The former task is extremely easy and the latter extremely difficult. This consideration of words is important to the language acquisition process. Children must segment the speech they hear into the appropriate-sized units in order to learn a language. If we were to say that a child learning language has heard words when what has been heard was a continuous stream of speech that was not understood, then, clearly, we would not have provided a good description of the stimulus input that the child has received. Accordingly, we need a term for a continuous period of speech that does not carry with it presumptions about the decomposition of the speech.

Children understand what is spoken through two methods. First, input to children is simplified by comparison with speech among adults. Adults talk to children more slowly, in shorter utterances, with repetition of key words, and in higher pitch than when they talk to other adults. This makes it easier for children to identify the units (i.e. words) that make up the utterance. Second, in conjunction with this environmental help, children selectively attend to stressed elements of the adult utterance and, to a large extent, ignore the rest. Since the referential words of an utterance are typically the ones that are stressed (and repeated) in adult speech to children, this means that children will extract the major content words initially from a sentence. It is because of this selective filtering of the input that children’s own initial utterances are composed largely of content words and lack the functor words (such as articles and prepositions) that are unstressed in adult speech. It is this that gives children’s speech its characteristic ‘telegraphic’ character in the early stages of word combination.

Induction and Concept Change
A child who learns a concept, such as dog, will learn the same concept as an adult in the sense that the concept will have the same extension for both child and adult. However, the adult’s and the child’s concepts will undoubtedly be different in spite of this. The adult’s concept will include much more information about the characteristic of dogs, their relations to other species and so forth.

The role of induction is to allow generalization of new information beyond the instances about which the information was acquired.

The Memory System
Memory is involved at each level of concept attainment – concrete, identity, classification, and formal. At any point in time, the type of information that is stored in memory and the form in which it is stored are related to the level which the individual has attained, to the individual’s unique mode of storing information, and also to the external conditions of learning the individual has experienced related to the particular concept.

Concrete Level
Attaining a concept at the concrete level involves attending to something – an object, event, quality, or relation – discriminating it from other objects, events, qualities, or relations, forming a representation of it, and storing it in secondary memory. Then, when the same object is experienced again, the stored representation is retrieved from secondary memory and used to test the incoming phenomenal representation as being the same or different. The concrete level representation of the object is presumed to be constructed by the individual, rather than being an automatically produced literal copy, photograph, or template.

Identity Level
To attain the same concept of an object as in the identity level as the concrete level for the first time requires having the concrete level image stored in secondary memory. Then, when the same object is experienced again but from a different spatiotemporal perspective, in a different context, or in a different sensory modality, the phenomenal image, held briefly in working memory, is tested against the earlier concrete-level image. According to Cognitive Learning and Development (CLD) theory, personas are able to move from the concrete to the identity level as they become able to generalize across spatiotemporal perspectives, sensory modalities, and contexts. This ability emerges with maturation and learning. The maturing child becomes able to test, for example, the incoming phenomenal image of two triangles against a concrete-level image and generalize that the forms are the same. The same individual also becomes able to discriminate either more properties of the triangular form or some of its less obvious properties and also to ignore orientation and other contextual information.

Classification Level
Attaining a concept at the beginning classificatory level, in comparison with the identity level, presumes that persons become able to attend to and discriminate more attributes and also attributes that are less obvious. They also are able to form more highly differentiated yet generalized representations and store and hold them in secondary memory. Further, they become able to generalize across at least two different examples of the same concept that necessarily have the same common defining attributes but that also have one or more different variable attributes. To do this, they must already have formed a concept of one of the examples at the identity level and must be able to do so for the other, so that each of the examples is recognized as the same across the different spatiotemporal orientations or contexts in which it may be experienced, or across the different sensory modalities, as the case may be. It is probable that concepts of at least two examples have been formed at the identity level before the beginning classificatory level is attained.

Children form may concepts at the beginning classificatory level before first grade, possibly before they have acquired the labels for the concept or any of its attributes. Many are still at the classificatory level years later, not having attained the formal level, at which time they may have some or all of the labels. When a label is available for a concept at the classificatory level, it may be stored initially as part of the trace along with image of a typical example and contextual information.

Formal Level
Attaining a concept at the beginning formal level has several prerequisites. The person will readily be able to categorize newly encountered instances as members of certain concepts and therefore as nonmembers of other concepts. Also, the person will be able to discriminate the defining attributes of the particular concept. Another perquisite is that the person will have the names of the defining attributes and also of the concept itself. The primary test of whether the concept has been attained at the formal level is whether the person, when encountering examples and nonexamples of the concept, can evaluate them as examples or nonexamples on the basis of the presence or absence of the defining attributes of the concept. This can be illustrated with the concept tree. When a person encounters two instances of a plant, one of which is a tree and the other a shrub, the person must first identify one properly as a tree, and then indicate why it is so categorized on the basis of the defining attributes of tree.

Fuzzy-trace theory
According to Fuzzy-trace theory, we have two separate memory processes: verbatim and gist. These two traces begin to develop at different times as well as at a different pace. Children as young as 4 years-old have verbatim memory, memory for surface information, which increases up to early adulthood, at which point it begins to decline. On the other hand, our capacity for gist memory, memory for semantic information, increases up to early adulthood, after which point it is consistent through old age. Furthermore, our reliance on gist memory traces in reasoning increases as we age.