Our society has identified two extremes in intelligence. How are these differences identified? (for psychology class)

The two extremes in intelligence levels that our society has defined are intellectual disability (significantly lower than average intelligence) and giftedness (far above average intelligence). Individual extremes for measures of intelligence are often identified through scores on intelligence tests.

use the comments section bro

the correct answer is moro reflex. this is usually witnessed in infants normally up to the age of 4-5 months (in some cases maybe more)  

it is caused by a sudden loss of support that makes the baby feel as if he or she is falling or is going to fall and hence the flinging of the arms and crying.