Researcher: All defects in short-term memory are caused by a malfunction of a part of the brain called the hippocampus. In short-term memory, the mind holds a piece of information for only a few moments, after which it is either stored in long-term memory or forgotten. Learning is the accumulation of new information in long-term memory. Thus, whenever a child exhibits a learning deficit, the hippocampus is malfunctioning. The reasoning in the researcher's argument is most vulnerable to criticism on the grounds that this argument ['draws a general conclusion based on too small a sample of learning deficits', 'presumes, without giving justification, that all learning deficits in children involve shortterm memory', 'presumes, without giving justification, that short-term memory is disabled whenever the hippocampus is disabled', 'takes for granted that learning deficits in adults have a cause unrelated to the cause of learning deficits in children']