Research design
Developmental psychologists have a number of methods to study changes in individuals over time.
In a longitudinal study, a researcher observes many individuals born at or around the same time (a cohort) and carries out new observations as members of the cohort age. This method can be used to draw conclusions about which types of development are universal (or normative) and occur in most members of a cohort. Researchers may also observe ways in which development varies between individuals and hypothesize about the causes of variation observed in their data. Longitudinal studies often require large amounts of time and funding, making them unfeasible in some situations. Also, because members of a cohort all experience historical events unique to their generation, apparently normative developmental trends may in fact be universal only to their cohort.
In a cross-sectional study, a researcher observes differences between individuals of different ages at the same time. This generally requires less resources than the longitudinal method, and because the individuals come from different cohorts, shared historical events are not so much of a confounding factor. By the same token, however, cross-sectional research may not be the most effective way to study differences between participants, as these differences may result not from their different ages but from their exposure to different historical events.
An accelerated longitudinal design or cross-sequential study or cohort-sequential design combines both methodologies. Here, a researcher observes members of different birth cohorts at the same time, and then tracks all participants over time, charting changes in the groups. By comparing differences and similarities in development, one can more easily determine what changes can be attributed to individual or historical environment, and which are truly universal. Clearly such a study can be even more resource-consuming than a longitudinal study.
Additionally, these are all correlational, not experimental, designs, and so one cannot readily infer causation from the data they yield. Nonetheless, correlational research methods are common in the study of development, in part due to ethical concerns. In a study of the effects of poverty on development, for instance, one cannot easily randomly assign certain families to a poverty condition and others to an affluent one, and so observation alone has to suffice.
Stages of development
Pre-natal development
See also: Pre-natal development and Pre- and perinatal psychology
Pre-natal development is of interest to psychologists investigating the context of early psychological development. For example, some primitive reflexes arise before birth and are still present in newborns. One hypothesis is that these reflexes are vestigial and have limited use in early human life. Piaget's Theory of cognitive development suggested that some early reflexes are building blocks for infant sensorimotor development. For example the tonic neck reflex may help development by bringing objects into the infant's field of view. Other reflexes, such as the walking reflex disappear to be replaced by more sophisticated voluntary control later in infancy. This may be because the infant gains too much weight after birth to be strong enough to use the reflex, or because the reflex and subsequent development are functionally different. It has also been suggested that some reflexes (for example the moro and walking reflexes) are predominantly adaptations to life in the womb with little connection to early infant development Primitive reflexes reappear in adults under certain conditions, such as neurological conditions like dementia or traumatic lesions.
Ultrasound has shown that infants are capable of a range of movements in the womb, many of which appear to be more than simple reflexes By the time they are born, infants can recognise and have a preference for their mother's voice suggesting some pre-natal development of auditory perception[ Pre-natal development and birth complications may also be connected to neurodevelopmental disorders, for example in schizophrenia. With the advent of cognitive neuroscience, embryology and the neuroscience of pre-natal development is of increasing interest to developmental psychology research.
Infancy
Main articles: Infant and child psychology and Infant cognitive development
From birth until the onset of speech, the child is referred to as an infant. Developmental psychologists vary widely in their assessment of infant psychology, and the influence the outside world has upon it, but certain aspects are relatively clear.
The majority of a newborn infant's time is spent in sleep. At first this sleep is evenly spread throughout the day and night, but after a couple of months, infants generally become diurnal.
Infants can be seen to have 6 states, grouped into pairs:
- quiet sleep and active sleep (dreaming, when REM occurs)
- quiet waking, and active waking
- fussing and crying
Infants respond to stimuli differently in these different states
Habituation (see above) has been used to discover the resolution of perceptual systems, suggesting that infants basic perceptual abilities develop before acquisition of object permanence.
- Vision is significantly worse in infants than in older children. Infant sight, blurry in early stages, improves over time. Colour perception similar to that seen in adults has been demonstrated in infants as young as four months, using habituation methods
- Hearing is well-developed prior to birth, however, and a preference for the mother's heartbeat is well established. Infants are fairly good at detecting the direction from which a sound comes, and by 18 months their hearing ability is approximately equal to that of adults.
- Smell and taste are present, with infants showing different expressions of disgust or pleasure when presented with pleasant odors (honey, milk, etc) or unpleasant odors (rotten egg) and tastes (e.g. sour taste). There is good evidence for infants preferring the smell of their mother to that of others
- Language : infants of around six months can differentiate between phonemes in their own language, but not between similar phonemes in another language. At this stage infants also start to babble, producing phonemes.
- Touch is one of the better developed senses at birth, being one of the first to develop inside the womb. This is evidenced by the primitive reflexes described above, and the relatively advanced development of the somatosensory cortex
- Pain : Infants feel pain similarly, if not more strongly than older children but pain-relief in infants has not received so much attention as an area of research
An early theory of infant development was the Sensorimotor stage of Piaget's Theory of cognitive development. Piaget suggested that an infant's perception and understanding of the world depended on their motor development, which was required for the infant to link visual, tactile and motor representations of objects. According to this view, it is through touching and handling objects that infants develop object permanence, the understanding that objects are solid, permanent, and continue to exist when out of sight
Special methods are used to study infant behavior.
Piaget's Sensorimotor Stage comprised six sub-stages (see sensorimotor stages for more detail). In the early stages, development arises out of movements caused by primitive reflexes. Discovery of new behaviours results from classical and operant conditioning, and the formation of habits. From eight months the infant is able to uncover a hidden object but will persevere when the object is moved. Piaget's evidence for a complete understanding of object permanence before 18 months was the infant's failure to look for an object where it was last seen. Instead infants continue to look for an object where it was first seen, committing the "A-not-B error".
Later researchers have developed a number of other tests which suggest that younger infants understand more about objects than first thought. These experiments usually involve a toy, and a crude barrier which is placed in front of the toy, and then removed, repeatedly. Before the age of eight to nine months, infants inability to understand object permanence extends to people, which explains why infants at this age do not cry when their mothers are gone ("Out of sight, out of mind.").
There are critical periods in infancy and childhood during which development of certain perceptual, sensorimotor, social and language systems depends crucially on environmental stimulation. Feral children such as Genie, deprived of adequate stimulation, fail to acquire important skills which they are then unable to learn in later childhood. The concept of critical periods is also well established in neurophysiology, from the work of Hubel and Wiesel among others. Some feel that classical music, particularly Mozart is good for an infant's mind. While some tentative research has shown it to be helpful to older children, no conclusive evidence is available involving infants.
Babyhood
Intelligence is demonstrated through the use of symbols, language use matures, and memory and imagination are developed. Thinking is done in a nonlogical, nonreversible manner. Egocentric thinking predominates.
Socially, toddlers are little people attempting to become independent at this stage, which they are commonly called the " terrible twos". They walk, talk, use the toilet, and get food for themselves. Self-control begins to develop. If taking the initiative to explore, experiment, risk mistakes in trying new things, and test their limits is encouraged by the caretaker(s) the child will become autonomous, self-reliant, and confident. If the caretaker is overprotective or disapproving of independent actions, the toddler may begin to doubt their abilities and feel ashamed for the desire for independence. The child's autonomic development will be inhibited, and be less prepared to successfully deal with the world in the future.
Early childhood
Also called as "Pre-school age", "Pre-gang age", "Exploratory age" and "Toy age".
When children attend preschool, they broaden their social horizons and become more engaged with those around them. Impulses are channeled into fantasies, which leaves the task of the caretaker to balance eagerness for pursuing adventure, creativity and self expression with the development of responsibility. If caretakers are properly encouraging and consistently disciplinary, children are more likely to develop positive self-esteem while becoming more responsible, and will follow through on assigned activities. If not allowed to decide which activities to perform, children may begin to feel guilt upon contemplating taking initiative. This negative association with independence will lead them to let others make decisions in place of them.
Late Childhood
In middle childhood, intelligence is demonstrated through logical and systematic manipulation of symbols related to concrete objects. Operational thinking develops, which means actions are reversible, and egocentric thought diminishes.
Children go through the transition from the world at home to that of school and peers. Children learn to make things, use tools, and acquire the skills to be a worker and a potential provider. Children can now receive feedback from outsiders about their accomplishments. If children can discover pleasure in intellectual stimulation, being productive, seeking success, they will develop a sense of competence. If they are not successful or cannot discover pleasure in the process, they may develop a sense of inferiority and feelings of inadequacy that may haunt them throughout life. This is when children think of them selves as industrious or as inferior.
Adolescence
Main article: Adolescent psychology
Adolescence is the period of life between the onset of puberty and the full commitment to an adult social role, such as worker, parent, and/or citizen. It is the period known for the formation of personal and social identity (see Erik Erikson) and the discovery of moral purpose (see William Damon). Intelligence is demonstrated through the logical use of symbols related to abstract concepts and formal reasoning. A return to egocentric thought often occurs early in the period. Only 35% develop the capacity to reason formally during adolescence or adulthood. (Huitt, W. and Hummel, J. January 1998)
It is divided into two parts namely:
1. Early Adolescence: 13 to 17 years and
2. Late Adolescence: 17 to 18 years
The adolescent unconsciously explores questions such as "Who am I? Who do I want to be?" Like toddlers, adolescents must explore, test limits, become autonomous, and commit to an identity, or sense of self. Different roles, behaviors and ideologies must be tried out to select an identity. Role confusion and inability to choose vocation can result from a failure to achieve a sense of identity.
Early adulthood
The person must learn how to form intimate relationships, both in friendship and love. The development of this skill relies on the resolution of other stages. It may be hard to establish intimacy if one has not developed trust or a sense of identity. If this skill is not learned the alternative is alienation, isolation, a fear of commitment, and the inability to depend on others.
A related framework for studying this part of the life span is that of Emerging adulthood, introduced in 2000 by Jeffrey Arnett. Scholars of emerging adulthood are interested not only in relationship development (focusing on the role of dating in helping individuals settle on a long-term spouse/partner), but also the development of sociopolitical views and occupational choice.
Middle age
Middle adulthood generally refers to the period between ages 40 to 60. During this period, the middle-aged experience a conflict between generativity and stagnation. They may either feel a sense of contributing to the next generation and their community or a sense of purposelessness.
Physically, the middle-aged experience a decline in muscular strength, reaction time, sensory keenness, and cardiac output. Also, women experience menopause and a sharp drop in the hormone estrogen. Men do have an equivalent to menopause, it is called "Andropause," which is a hormone fluctuation with physical and psychological effects similar to menopause. Lowered testosterone levels result in mood swings and a decline in sperm count and speed of ejaculation and erection. Most men and women remain capable of sexual satisfaction after middle age.
Old age
This stage generally refers to those over 60-80 years. During old age, people experience a conflict between integrity vs. despair. When reflecting on their life, they either feel a sense of accomplishment or failure.
Physically, older people experience a decline in muscular strength, reaction time, stamina, hearing, distance perception, and the sense of smell. They also are more susceptible to severe diseases such as cancer and pneumonia due to a weakened immune system. Mental disintegration may also occur, leading to Dementia or Alzheimer's Disease. However, partially due to a lifetime's accumulation of antibodies, the elderly are less likely to suffer from common diseases such as the cold.
Whether or not intellectual powers increase or decrease with age remains controversial. Longitudinal studies have suggested that intellect declines, while cross-sectional studies suggest that intellect is stable. It is generally believed that crystallized intelligence increases up to old age, while fluid intelligence decreases with age.
In Western developed societies, mothers (and women generally) were emphasized to the exclusion of other caregivers, particularly as the traditional role of the father was more the breadwinner, and less the direct caregiver of an infant, he has been traditionally viewed as impacting an infant indirectly through interactions with the mother of the child.
The emphasis of study has shifted to the primary caregiver (regardless of gender or biological relation), as well as all persons directly or indirectly influencing the child (the family system). The roles of the mother and father are more significant than first thought as we moved into the concept of primary caregiver.
Affirming a role for fathers, studies have shown that children as young as 15 months benefit significantly from substantial engagement with their father. In particular, a study in the U.S.A. and New Zealand found the presence of the natural father was the most significant factor in reducing rates of early sexual activity and rates of teenage pregnancy in girls. Covariate factors used included early conduct problems, maternal age at first childbirth, race, maternal education, father's occupational status, family living standards, family life stress, early mother-child interaction, measures of psychosocial adjustment and educational achievement, school qualifications, mood disorder, anxiety disorder, suicide attempts, violent offending, and conduct disorder. Further research has found fathers have an impact on child academic performance, including involved nonresident fathers. However, father absence is associated with a range of negative outcomes for children, including child and later criminal behavior.
Historical antecedents
The modern form of developmental psychology has its roots in the rich psychological tradition represented by Aristotle, Tabari, Rhazes, and Descartes. William Shakespeare had his melancholy character Jacques (in As You Like It) articulate the seven ages of man: these included three stages of childhood and four of adulthood. In the mid-eighteenth century Jean Jacques Rousseau described three stages of childhood: infans (infancy), puer (childhood) and adolescence in Emile: Or, On Education. Rousseau's ideas were taken up strongly by educators at the time.
In the late nineteenth century, psychologists familiar with the evolutionary theory of Darwin began seeking an evolutionary description of psychological development; prominent here was G. Stanley Hall, who attempted to correlate ages of childhood with previous ages of mankind.
A more scientific approach was initiated by James Mark Baldwin, who wrote essays on topics that included Imitation: A Chapter in the Natural History of Consciousness and Mental Development in the Child and the Race: Methods and Processes. In 1905, Sigmund Freud articulated five psychosexual stages. Later, Rudolf Steiner articulated stages of psychological development throughout human lif By the early to mid-twentieth century, the work of Vygotsky and Piaget, mentioned above, had established a strong empirical tradition in the field.
Children Develop Their Parents By Anne Hansen
Developmental psychology offers numerous theories about human development. The perception is that the science concentrates on the stages of childhood when, in fact, it advances many theories on stages of parent development. However, the textbook examples are never quite as colorful as the examples parents live from day to day.
Textbooks explain how children begin their search for independence around the age of two or three. The books advise parents to start giving children simple choices at this age. They cite choices such as breakfast foods or colors of socks or shirts. They offer little about the pre-school girl who fancies herself to be a runway model and chooses to change her clothes five times a day. They completely overlook the “all I do is laundry” stage the parent is experiencing.
The viewpoints, personality and family history of a parent influence how the parent interacts with the child as much as the personality and behavior of the child influences
how the parent chooses to raise the child. It is a dynamic interaction, or in simpler terms, a two way street. Our children adapt to us as we adapt to them, although in my opinion, there is more adaptation on the part of the parent.
For example, parents determine bedtime. While 8:30 PM seems reasonable for a ten-year-old, what happens if the child is unable to fall asleep? The parent adapts and allows quiet reading in bed.
A strong-willed child requires more creative discipline techniques then his mild-mannered brother or sister. A slow learner will try the patience of a tired parent at homework time more than the child who excels in school will. A fussy eater can make a creative cook out of any mom or dad. The child, by the way he or she behaves, determines how the parent will behave.
When my friend called the other day to lament the stage of life she is in with her oldest daughter – teaching her to drive, I smiled and listened. First, she need not worry. Her daughter is intelligent, responsible, and considerate. She will not prove to be a reckless driver. But who can deny that it takes great faith to sit in the passenger seat of a car with a 15 or 16 year old behind the wheel as they begin to maneuver the streets of Southern California? Danger looms at every stop sign and left turn.
My friend was curious about how I survived teaching four children to drive. It was a simple method: let Daddy do it. She had already figured this out and we agreed it is one way of getting through this stage of parenting.
She went on to explain her realization that this was a major step toward independence for her daughter. As soon as the girl secures a driver’s license, she will not need her mom as much. The trips back and forth to school and sports and music lessons could be taken off mom’s calendar and put on the daughter’s.
My friend’s life is changing. As her teenage daughter moves quickly towards total independence, the mom is moving to a stage of less control and responsibility.
She is aware that when her daughter finally earns a driver’s license college will be right around the corner and then life as her family has known it for 18 years will be over. Their “cocoon”, as she called it, would not be the same and she was feeling those first pangs of detachment that come when a parent faces the emerging adulthood of their oldest child.
Her question was, “ How do you handle it?”
I advise my friend to slow down and spend as much time as possible with her daughter. Celebrate the emerging adulthood and independence. Understand this is a special stage, just as learning to walk was a special stage. Praise her as she successfully takes
the necessary steps toward going out into the world on her own and recognize that you have given her the best care and nurturing possible.
While doing all of this I sincerely hope that my friend does some celebrating of her own.
Welcome to Stages in Pregnancy your resource from before the very early pregnancy signs all the way through the signs of labor.
Stages in Pregnancy will guide you through your fertility years, with the pregnancy first weeks and the three trimesters through post partum.
In the beginning stages learn how to effectively chart your fertility signs to pinpoint ovulation and identify possible infertility. We even offer a free fertility chart - the link is in the Fertility Charting page.
My Qualifications for Stages in Pregnancy
I have been through the throes of trying to conceive, battling and winning over minor infertility and ultimately giving birth to five healthy beautiful babies Over the past 15 years I have gone through gestational diabetes during pregnancy twice, preterm labor 3 times, premature birth twice. I've suffered through two miscarriages, fought and won the battle against minor infertility.
It was my passion in learning all I could about the human fertility cycle that led down a path of research. I read many books on fertility and pregnancy, interviewed OB/GYN doctors, nurses and midwives. Most importantly through the years I have conversed with women just like you - on this path to motherhood.
I've written extensively of my own journey to motherhood. I've had two books published on the subject of fertility and pregnancy.
My passion is to help other women who want to become pregnant. or already are pregnant with my gentle tips and advice.
Start with our Fertility Charting Basics
Our SiP Calculator can be used to calculate ovulation and be used as a Pregnancy Conception Calculator to determine the pregnancy due date.
Learn effective fertility tracking with fertility charts. By charting all your fertility signs you can know where you are in your cycle and possibly even detect pregnancy before a home pregnancy test can!
Help With Pregnancy
Be aware of the signs of a pregnancy complication and find out why progesterone cream and pregnancy go hand in hand in combating preterm labor and early miscarriages.
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