Todd is an expert in fixing computers. One of his new employees asks how he knew where the problem was. Todd was surprised that he couldn't explain it, that he "just knew." Should Todd be concerned about his decreasing mental abilities?

Answer: No, Todd should not necessarily be concerned about his decreasing mental abilities simply because he couldn't explain how he knew where the problem was on a computer. What Todd is experiencing is a phenomenon known as "tacit knowledge" or "intuition," which is common in many experts. Tacit knowledge refers to the kind of knowledge that is difficult to transfer to another person by writing it down or verbalizing it. It's the "know-how" that's acquired through experience, practice, and the repeated handling of similar situations.

Experts like Todd often make rapid, intuitive decisions, especially in their areas of expertise, where they have a vast amount of experience to draw from. This ability to "just know" is actually a sign of Todd's expertise and deep understanding of his field, rather than a sign of any cognitive decline.