the various abilities of nonhuman animals to solve problems in their environment through mechanisms of learning and animal cognition. Psychologists formerly thought that animal intelligence was best measured relative to human skills, with a linear progression of intelligence from simple to complex organisms. Research has revealed, however, that intelligence can take many forms and is best understood in the context of the particular problems that each species faces. For example, swarm intelligence is the cumulative problem-solving ability of a group of animals of one species, such as an ant colony or a flock of birds. See also comparative cognition.