Final answer:
The child's correct assertion that Bob is older than Fred, after being told the respective ages in sequence, demonstrates the cognitive ability known as transductive inference, part of early logical thinking and understanding the transitive property.
Step-by-step explanation:
The child who was told that Bob is older than Sally, and Sally is older than Fred, and then correctly identifies that Bob is older than Fred is demonstrating transductive inference. This type of reasoning shows the child's ability to relate one situation to another when given a sequence of information, even if they are not directly compared. It's an example of early logical thinking and cognitive development, where children begin to understand and apply the rules of ordering and hierarchy. This does not directly relate to class inclusion, divergent thinking, or mnemonic devices, but it's a sign of understanding the transitive property (if A > B and B > C, then A > C) in basic logic.