A disadvantage of longitudinal studies is that differences observed among participants of different ages are usually due to differences in the environment in which they were reared differences observed among participants of different ages are usually due to differences in the environment in which they were reared A participants who drop out during the course of the study may be different in important ways from ones who do not drop out participants who drop out during the course of the study may be different in important ways from ones who do not drop out B unfamiliarity with testing situations can put older participants at a disadvantage unfamiliarity with testing situations can put older participants at a disadvantage C personality traits do not remain constant across the life span personality traits do not remain constant across the life span D men and women confront different developmental crises in the course of their lives because of their different social roles