Developmental Psychology: The Five Stages Of Human Development

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Human development is studied by the broad field of psychology and within the subfield of developmental psychology. Developmental psychology is defined as the study of stability and change throughout the life course. It has proposed the idea that all humans follow a predictable developmental trajectory (Neil 2006). The process of human development begins from infancy to old age. The first half of human development from infancy to adolescent is a phase of growth or maturity. The second half of human development from adulthood to old age is a phase of adulthood, during which individuals have completed their growth and are ready to assume their status in the society. The phase of adulthood is customarily subdivided into young adulthood,

It is begun to consider a distinct phase of life not only by the increase in the life expectancy but also by a decrease in the end of childbearing. The increase of life expectancy gives rise to a separation of middle adulthood from old age, while the latter implies a relative decrease in time spent in rearing children makes midlife separate from young adulthood (Moen

There are different opinions considering who is included in mid-adulthood. The most frequently used definition of mid-adulthood is based on the chronological age. There is a different opinion among the scholars regarding what age range encompasses mid-adulthood (Staudinger 2001). Some have considered that middle age begins at 30yrs and end at 75yrs (Lachman 2001), for Jung ( 1933) middle age starts from 40 and ends at 65yrs, for Havighurst (1972) middle age starts at 30 and ends at 60yrs. Others have used a lower limit as young as age 30 and an upper limit as late as age 70 as the age range of midlife (Dittmann et al.2005), still, others, have an opinion that it starts at 40 and ends at 64yrs (Bjorklund et al 2008). Hence there is no clear demarcation with regard to the boundaries of midlife.
Despite these disagreements, there exists common agreement regarding when midlife begins and ends. The most common conception is that midlife begins at 40 and ends at 60 or 65yrs (Lachman 2004). Thus currently age 40 is considered as the modal entry year and age 60 is the modal exist year, during this time period there occurs tremendous variability (Lachman et al.1995), hence it is customarily further subdivided into early middle age which extends from age 40 to age 49yrs and advanced middle age which extends from age 50 to age 59yrs (Hurlock