MCAT Behavioral Sciences Review - Kaplan Test Prep 2021–2022
Cognition, Consciousness, and Language
After Chapter 4.1, you will be able to:
· List the steps in the information processing model of cognition
· Describe the effects of aging, heredity, and environment on cognitive function
· Recall Piaget’s four stages of cognitive development and their key features
The study of cognition looks at how our brains process and react to the incredible information overload presented to us by the world. Cognition, overall, is not a uniquely human trait, but we are certainly the most advanced species on the planet in terms of complex thought. As described in the introduction, the frontal lobe is disproportionately large in our subspecies; a comparison to our recent anthropological ancestors demonstrates that our skull is shaped to accommodate this enlarged lobe, as shown in Figure 4.1.
Figure 4.1. Skulls of H. sapiens (left) and H. neanderthalensis (right)
INFORMATION PROCESSING MODEL
In the 1950s, much of science and engineering turned toward the production of computers and artificial intelligence. It was noted that certain steps were required in order to use a computer to store and process information. First, the information must be encoded in a language that the computer understands. Then, the information must be stored in such a way that it can be found later. Finally, the computer must be able to retrieve that information when required.
Psychologists took this model of information processing and applied it to the human brain. They theorized that the brain is somewhat like a computer. It must encode information into a series of chemical and electrical signals. Then, the brain must be able to store this information such that it can be retrieved when needed. Then, there must be a process by which the brain is able to retrieve information.
The manner in which information is encoded, stored, and retrieved has been a consistent source of debate. One prominent theory, Paivio's dual-coding theory, states that both verbal association and visual images are used to process and store information. For example, the word “dad” can recall some information, and the picture of “dad” can recall that same information. The fact that we can code this information two different ways builds redundancy and increases the chance that the information can be retrieved and used effectively when cued, much like search engine optimization within a computer program.
However, the human brain is not a computer. While the computer analogy creates a simple paradigm by which information is processed by the brain, it does not tell the whole story. The human brain doesn’t just handle information in the form of facts: it also handles emotions, sensations such as smell and taste, as well as memories. As discussed in Chapter 3 of MCAT Behavioral Sciences Review, encoding, storage, and retrieval are often flavored by context and emotion.
The key memory processes of encoding, storage, and retrieval are covered in Chapter 3 of MCAT Behavioral Sciences Review.
The information processing model has four key components, or pillars:
· Thinking requires sensation, encoding, and storage of stimuli.
· Stimuli must be analyzed by the brain (rather than responded to automatically) to be useful in decision making.
· Decisions made in one situation can be extrapolated and adjusted to help solve new problems (also called situational modification).
· Problem solving is dependent not only on the person’s cognitive level, but also on the context and complexity of the problem.
Cognitive development is the development of one’s ability to think and solve problems across the life span. Interestingly, during childhood, cognitive development is limited by the pace of brain maturation. Early cognitive development includes learning control of one’s own body as well as learning how to interact with and manipulate the environment. Early cognitive development is characterized by mastering the physical environment. As physical tasks are mastered, a new challenge looms for a developing child: abstract thinking. As discussed in Chapter 1 of MCAT Behavioral Sciences Review, social skills also develop during the lifetime.
As you will see during our review of Piaget’s stages of cognitive development, the development of the ability to think abstractly is developed throughout childhood. The development of abstract thinking is also dependent upon increases in working memory and mental capacities. As the brain develops, the ability to process information in an abstract manner also develops.
Abstract thought, the ability to think about things that are not physically present, can be lost in some mental disorders. For example, a common cognitive test with schizophrenic patients is to ask them to interpret a cliché, such as Don’t count your chickens before they hatch. These patients have concrete thinking and will give an answer focused on the chickens themselves—not the underlying concept.
Piaget’s Stages of Cognitive Development
Jean Piaget was one of the most influential figures in developmental psychology. Piaget’s model of cognitive development proposes that there are qualitative differences between the way that children and adults think, and that these differences can be explained by dividing the life span into four stages of cognitive development: sensorimotor, preoperational, concrete operational, and formal operational. Piaget believed that passage through each of these stages was a continuous and sequential process in which completion of each stage prepares the individual for the stage that follows.
Piaget’s stages of cognitive development:
· Concrete operational
· Formal operational
Before delving into the actual stages, we have to look at how Piaget explained learning. According to Piaget, infants learn mainly through instinctual interaction with the environment. For example, infants possess a grasping reflex. Through experience with this reflex, the infant learns that it is possible to grasp objects. Piaget referred to these organized patterns of behavior and thought as schemata. A schema can include a concept (What is a dog?), a behavior (What do you do when someone asks you your name?), or a sequence of events (What do you normally do in a sit-down restaurant?). As a child proceeds through the stages, new information has to be placed into the different schemata. Piaget theorized that new information is processed via adaptation. According to Piaget, adaptation to information comes about by two complementary processes: assimilation and accommodation. Assimilation is the process of classifying new information into existing schemata. If the new information does not fit neatly into existing schemata, then accommodation occurs. Accommodation is the process by which existing schemata are modified to encompass this new information.
The first stage in Piaget's model is the sensorimotor stage, starting at birth and lasting until about two years of age. In this stage, a child learns to manipulate his or her environment in order to meet physical needs and learns to coordinate sensory input with motor actions (hence the name sensorimotor). To explore their surroundings, infants in the sensorimotor stage begin to exhibit two types of behavior patterns called circular reactions, named for their repetitive natures. Primary circular reactions are repetitions of body movements that originally occurred by chance, such as sucking the thumb. Usually such behaviors are repeated because the child finds these behaviors soothing. Secondary circular reactions occur when manipulation is focused on something outside the body, such as repeatedly throwing toys from a high chair. These behaviors are often repeated because the child gets a response from the environment, such as a parent picking up the dropped toy. The key milestone that ends the sensorimotor stage is the development of object permanence, which is the understanding that objects continue to exist even when out of view. Object permanence is the idea behind “peek-a-boo,” shown in Figure 4.2. This game is so entertaining to young infants because they lack object permanence. Each time the adult reveals him- or herself, the child interprets it as though he or she has just come into existence. Object permanence marks the beginning of representational thought, in which the child has begun to create mental representations of external objects and events.
Figure 4.2. Peek-a-BooThis game depends on the child being in the sensorimotor stage, prior to the development of object permanence.
The preoperational stage lasts from about two to seven years of age and is characterized by symbolic thinking and egocentrism. Symbolic thinking refers to the ability to pretend, play make-believe, and have an imagination. Egocentrism refers to the inability to imagine what another person may think or feel. The preoperational stage also includes the inability to grasp the concept of conservation, which is the understanding that a physical amount remains the same, even if there is a change in shape or appearance. For example, imagine a child presented with two equal quantities of pizza. On one plate is a single large slice, while the other plate has the exact same quantity in two slices. A child in the preoperational stage will be unable to tell that the quantities are equal and will focus mainly on the number of slices on the plate rather than the actual quantity. Piaget believed that this flaw in cognition was due to centration, which is the tendency to focus on only one aspect of a phenomenon, for example the number of slices, while ignoring other important elements.
The concrete operational stage lasts from about 7 to 11 years of age. In this stage, children can understand conservation and consider the perspectives of others. This consideration results in the loss of egocentrism. Additionally, they are able to engage in logical thought as long as they are working with concrete objects or information that is directly available. These children have not yet developed the ability to think abstractly.
The formal operational stage starts around 11 years of age, and is marked by the ability to think logically about abstract ideas. Generally coinciding with adolescence, this stage is marked by the ability to reason about abstract concepts and problem solve. The difference between this type of thought and concrete operations is illustrated by Piaget’s pendulum experiment. Children were given a pendulum in which they could vary the length of the string, the weight of the pendulum, the force of the push, and the initial angle of the swing. They were asked to find out what determined the frequency of the swing. Children in the concrete operational stage manipulated the variables at random and even distorted the data to fit preconceived hypotheses. Adolescents, on the other hand, were able to hold all variables but one constant at a given time, proceeding methodically to discover that only the length of the string affects the frequency. The ability to mentally manipulate variables in a number of ways, generally within the scope of scientific experiments, is an important component of the formal operational stage, and is termed hypothetical reasoning.
Role of Culture in Cognitive Development
Cognitive development is very much related to culture, as one’s culture will determine what one is expected to learn. Some cultures will place a higher value on social learning, including cultural traditions and roles, while other cultures will value knowledge. In addition, one’s culture will also influence the rate of cognitive development as children are treated very differently from culture to culture.
Culture has profound effects on cognitive development, as well as social structure, rules, and mores. Culture is discussed in detail in Chapter 11 of MCAT Behavioral Sciences Review.
Lev Vygotsky, a prominent educational psychologist, proposed that the engine driving cognitive development is the child’s internalization of his or her culture, including interpersonal and societal rules, symbols, and language. As a child develops, his or her skills and abilities are still in formative stages. With help from adults or other children, those skills can develop further. That help may come in the form of instruction from a teacher or even watching another child perform the skill.
Lev Vygotsky is also a key figure in the psychology of identity. Along with Kohlberg, Freud, and Erikson, he proposed a staged system of identity formation. These theorists are discussed in Chapter 6 of MCAT Behavioral Sciences Review.
Cognitive Changes in Late Adulthood
Aging brings about many changes in cognition. Reaction time increases steadily in early adulthood, while time-based prospective memory—the ability to remember to perform a task at a specific time in the future—declines with age. Intellectual changes also occur; however, IQ changes have been found to be misleading. Early research into the field of intelligence and aging indicated that a substantial decline in IQ occurs between the ages of 30 and 40. In order to further elucidate what specific changes were occurring, intelligence itself was separated into two subtypes: fluid intelligence and crystallized intelligence. Fluid intelligence consists of solving new or novel problems, possibly using creative methods. Figuring out how to navigate through a new video game world involves the usage of fluid intelligence. Crystallized intelligence is more related to solving problems using acquired knowledge, and often can be procedural. For instance, working through a General Chemistry stoichiometry problem requires crystallized intelligence since it involves recall of the proper equations and the steps taken to work through the calculations. Fluid intelligence was shown to peak in early adulthood but decline with age, while crystallized intelligence peaked in middle adulthood and remains stable with age.
Decline in intellectual abilities in adulthood has been linked with how long an older adult retains the ability to function in what are known as activities of daily living (eating, bathing, toileting, dressing, and ambulation). It appears, however, that this decline is not uniform. Certain characteristics, such as higher level of education, more frequent performance of intellectual activities, socializing, and a stimulating environment have been found to be protective against intellectual decline.
Intellectual decline is not always benign. Some types of intellectual decline are very common and indicate a progressive loss of function beyond that of old age. Disorders and conditions that are characterized by a general loss of cognitive function are collectively known as dementia. Dementia often begins with impaired memory, but later progresses to impaired judgment and confusion. Personality changes are also very common as dementia progresses. The most common cause of dementia is Alzheimer’s disease. Vascular (multi-infarct) dementia, caused by high blood pressure and repeated microscopic clots in the brain, is also a very common cause. It is also important to note that people with dementia often require full-time supportive care in order to carry out activities of daily living. This causes tremendous stress on families, including children and spouses of those with dementia, as the care for the person with dementia often falls on family members.
Alzheimer’s disease accounts for approximately 60 to 80% of all dementia cases.
HEREDITY, ENVIRONMENT, AND BIOLOGIC FACTORS
Cognition can be affected by a wide variety of conditions. These may include actual problems with the brain itself (organic brain disorders), genetic and chromosomal conditions, metabolic derangements, and long-term drug use. The environment can also affect both cognitive development and day-to-day cognition.
Parenting styles may influence cognitive development by reward, punishment, or indifference for an emerging skill. In addition, genetics can predispose to a state that may make cognitive development difficult. For example, many genetic and chromosomal diseases such as Down syndrome and Fragile X syndrome are associated with delayed cognitive development. Antisocial personality disorder has also been shown to have a strong genetic component. The presence of genes for this disorder may make it difficult for a child to appreciate the rights of others.
Intellectual disabilities in children can also be caused by chemical exposures, illness, injury, or trauma during birth. Alcohol use during pregnancy can cause fetal alcohol syndrome, which results in slowed cognitive development and distinct craniofacial features, shown in Figure 4.3. Infections in the brain may result in electrical abnormalities and slowed development. Complications during birth—especially those causing reduced oxygen delivery to the brain—may also affect cognition. Finally, reduced cognition can also occur following trauma to the brain, as occurs with shaken baby syndrome.
Figure 4.3. Craniofacial Features of Fetal Alcohol Syndrome
However, not all cognitive decline in adulthood is slow. If there has been a rapid decline in cognition, this may be the result of delirium. Delirium is rapid fluctuation in cognitive function that is reversible and caused by medical (nonpsychological) causes. It can be caused by a variety of issues, including electrolyte and pH disturbances, malnutrition, low blood sugar, infection, a drug reaction, alcohol withdrawal, and pain.
The delirium associated with alcohol withdrawal, called delirium tremens, can be life threatening. As a depressant, alcohol is the only major drug of abuse in which both overdose and withdrawal can be lethal.
MCAT Concept Check 4.1:
Before you move on, assess your understanding of the material with these questions.
1. The three steps in the information processing model are:
2. An elderly man is taken to his doctor by his daughter. His daughter says that during the past two days, he has been speaking to his wife who has been deceased for four years. Prior to that, he was completely normal. The elderly man most likely has:
3. List Piaget’s four stages of cognitive development and the key features of each.