Early psychologists, attempting to measure animal intelligence, found

A) evidence for intelligence only in primates.
B) evidence for intelligence in vertebrates, but not in invertebrates.
C) intelligence was directly related to brain size.
D) animals that seemed very intelligent on some tasks seemed very unintelligent on others.

Animal Intelligence

The capacity of animals to process information, learn from experience, solve problems, and adapt to their environments.

Vertebrates

Animals with a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fish.

Invertebrates

Animals that lack a vertebral column, or backbone, including species such as insects, mollusks, and crustaceans.