Final answer:
Increased shivering and vasoconstriction are the mechanisms that indicate effective learning when the body temperature is lower than the set point.
Step-by-step explanation:
The hypothalamus in the brain maintains the body's core temperature by initiating various mechanisms when the body temperature is lower than the set point. In this case, increased shivering and vasoconstriction would be the mechanisms that indicate effective learning. Shivering generates heat through muscle contractions, while vasoconstriction reduces blood flow to the skin, conserving heat.