Final answer:
Excessive cortisol early in life can lead to a permanent blunting or acceleration of emotional responses, impacting cognitive function and emotional regulation.
Step-by-step explanation:
The characteristic that is a potential effect of too much cortisol early in life is the permanent blunting or accelerating of emotional responses. Elevated levels of cortisol, especially during critical periods of development, can have long-term effects on the brain.
High cortisol can impair cognitive function, suppress the immune system, alter metabolism, and lead to conditions such as Cushing's syndrome, which is associated with symptoms like weight gain, depression, and anxiety.
Excessive cortisol production can also cause changes in the hippocampus, an area crucial for memory and learning, which might impact emotional regulation and cognitive abilities.