FIGURE 1.3 Continuous and discontinuous growth Depending on how it is viewed, changes in height can be viewed as either continuous or discontinuous. (a) Examining a boy’s height in absolute terms from birth to 18 years makes the growth look gradual and continuous (from Tanner, 1961). (b) Examining the increases in the same boy’s height from one year to the next over the same period shows rapid growth during the first 2½ years, then slower growth, then a growth spurt in adolescence, then a rapid decrease in growth; viewed this way, growth seems discontinuous.