The researcher concludes that whenever a child exhibits a learning deficit, the hippocampus is malfunctioning. Why? Because, if memory fails to work correctly, it leads to a learning deficit. And all short-term memory failures are caused by hippocampus malfunctions.

This is the cookie-cutter flaw of confusing sufficiency and necessity. The author implicitly argues that hippocampus memory malfunctions always lead to learning deficits. Therefore, learning deficits are always the result of hippocampus malfunctions.

The problem is that we don’t know that—there could be learning deficits that are the result of factors other than hippocampus malfunctions.