The Salovey-Mayer model treats emotional intelligence as four abilities: perceiving, understanding, using and managing emotions. Why does defining it as abilities rather than as traits change what can be claimed for it?

B. Because an ability is tested against right answers and a trait is not.

An ability is assessed by performance — shown a face, which emotion is it? — so the construct is anchored outside the participant's opinion of themselves. Trait models import two problems: people with poor emotional skill are badly placed to notice, and the scores overlap so heavily with extraversion and agreeableness that it is unclear anything new is measured.