Why have some behavioral scientists criticized Piaget's developmental research?

• A. His findings were derived from cross-cultural samples
• B. His findings were often derived from observing his own children
• C. He used excessive statistical analysis
• D. He focused only on adults

Answer: (B)

The main idea is about generalizability and how the data were gathered. Piaget based many of his conclusions about cognitive development on close, qualitative observations of a small number of children, including his own. This narrow, non-representative sample raises questions about bias and whether the findings apply to children from different cultures, backgrounds, and settings. He also relied on informal observations and interviews rather than standardized, controlled measures, which modern researchers see as limiting the ability to verify and compare results across groups. Because the evidence mostly came from his family, many scientists question whether the patterns would hold in a broader population. That’s why this approach is criticized. Cross-cultural samples would be more convincing; excessive statistics weren’t part of his method; and his work focused on children rather than adults, not the other way around.