One psychological study investigated whether intelligence declines with age, Experimenters took subjects from different age groups, running from late childhood through old age,
administered IQ tests to each age group and then looked how the results changed from one
age group to another, What observation method did researchers use in this study?

The observation method that the researchers used in this psychological study is called the structured observation method.

The structured observation method (or systemic observation) involves data collection by researchers without the direct involvement with the research participants. The experimenters observe the participants using a structured data collection technique.

Thus, the observation method used by the researchers is the structured observation method.

Learn more about the Structured Observation Method at link

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