Editing Developmental psychology (section)

===Middle adulthood===
{{Main|Middle age}}
Middle adulthood generally refers to the period between ages 40 to 64. During this period, middle-aged adults experience a conflict between generativity and stagnation. Generativity is the sense of contributing to society, the next generation, or their immediate community. On the other hand, stagnation results in a lack of purpose.<ref>{{cite journal | vauthors = Helson R, Soto CJ | title = Up and down in middle age: monotonic and nonmonotonic changes in roles, status, and personality | journal = Journal of Personality and Social Psychology | volume = 89 | issue = 2 | pages = 194–204 | date = August 2005 | pmid = 16162053 | doi = 10.1037/0022-3514.89.2.194 }}</ref> The adult's identity continues to develop in middle-adulthood. Middle-aged adults often adopt opposite gender characeristics. The adult realizes they are half-way through their life and often reevaluate vocational and social roles. Life circumstances can also cause a reexamination of identity.<ref>{{cite journal |last1=Sokol |first1=Justin T. |title=Identity Development Throughout the Lifetime: An Examination of Eriksonian Theory |journal=Graduate Journal of Counseling Psychology |date=March 2009 |volume=1 |issue=2 |url=https://epublications.marquette.edu/gjcp/vol1/iss2/14/ }}</ref>  

Physically, the middle-aged experience a decline in muscular strength, reaction time, sensory keenness, and cardiac output. Also, women experience [[menopause]] at an average age of 48.8 and a sharp drop in the hormone [[estrogen]].<ref>{{cite journal | vauthors = Schoenaker DA, Jackson CA, Rowlands JV, Mishra GD | title = Socioeconomic position, lifestyle factors and age at natural menopause: a systematic review and meta-analyses of studies across six continents | journal = International Journal of Epidemiology | volume = 43 | issue = 5 | pages = 1542–1562 | date = October 2014 | pmid = 24771324 | pmc = 4190515 | doi = 10.1093/ije/dyu094 }}</ref> Men experience an equivalent endocrine system event to menopause. [[Andropause]] in males is a hormone fluctuation with physical and psychological effects that can be similar to those seen in menopausal females. As men age lowered testosterone levels can contribute to mood swings and a decline in [[spermatozoa|sperm]] count. Sexual responsiveness can also be affected, including delays in [[erection]] and longer periods of [[penile stimulation]] required to achieve [[ejaculation]].

The important influence of biological and social changes experienced by women and men in middle adulthood is reflected in the fact that depression is highest at age 48.5 around the world.<ref>{{cite journal | vauthors = Blanchflower DG, Oswald AJ | title = Is well-being U-shaped over the life cycle? | journal = Social Science & Medicine | volume = 66 | issue = 8 | pages = 1733–1749 | date = April 2008 | pmid = 18316146 | doi = 10.1016/j.socscimed.2008.01.030 | url = http://www.nber.org/papers/w12935.pdf }}</ref>