Which of the following is a weakness of Pavlov's study?

• A. The use of a salinometer implanted surgically prevented swallowing and caused deaths.
• B. The study used human subjects, which is inappropriate.
• C. The data were qualitative, not quantitative.
• D. There were too many subjects to manage.

Answer: (A)

The weakness being tested is ethical concerns and animal welfare in classic research. In Pavlov’s dog experiments, a surgically implanted salinometer was used to measure saliva, which disrupted normal functioning like swallowing and led to deaths. This raises serious moral issues about how animals are treated in research and calls into question the welfare standards under which the findings were obtained, which can also affect how we view the validity and acceptability of the results. The other options don’t fit: the study did not use humans, the data were quantitative rather than qualitative, and there’s no clear indication that the issue was simply “too many subjects to manage.”