The research design that involves testing groups of subjects of ...

[ap345]

The research design that involves testing groups of subjects of different ages multiple times and comparing their scores with their own scores in previous periods and with the scores of new groups of adults of the same ages is called
 
  longitudinal or long-term research.
  cross-sectional research.
  cross-sequential research.
  retesting research.

Question 2

When Schaie conducted cross-sectional research comparing the cognitive abilities of adults of different ages, he found
 
  a gradual increase in intellectual ability with age.
  a gradual decline in intellectual ability with age.
  a sudden decline in intelligence in middle adulthood.
  no age-related patterns of intellectual development.

[catron30]

Answer to Question 1

cross-sequential research.

Answer to Question 2

a gradual decline in intellectual ability with age.