Finally, Professor Smith Tested the Same Full-Term and Pre-Term Infants

Multiple Choice

Finally, Professor Smith tested the same full-term and pre-term infants again at 9 months of age. This time he showed them pictures with 12 objects repeatedly until their looking times decreased by 50% and then showed them new pictures with 18 objects. This is an example of

A) A cross-sectional study.
B) A longitudinal study.
C) A quasi-experiment.
D) A case study.