Cross-sectional research design (cont......)(psychology notes)

Here the research compares groups of 35, 45 and 55 year olds in terms of memory ability.  It may be possible to correlate age with memory by noting differences among the three different age groups. But does age alone account for memory ability differences?  There may be a cohort effect, meaning that different age groups share different formative cultural events such as economic, depression, war; growing up with television.  Thus, when researchers compare different age groups, is the difference between them on some psychological variable due to age or a cohort effect? 

cont........