A psychologist and an English professor have written a review of studies and concluded that pigs perform as well as or better than dogs on some tests of behavioral and cognitive sophistication, and they compare favorably to chimpanzees.

The review by Emory psychologist Dr. Lori Marino and visiting English Professor Christina M. Colvin, seeks to extrapolate results to deduce what we do and do not know about pigs. The areas they discuss include cognition, emotion, self-awareness, personality and social complexity.

They conclude that “pigs possess complex ethological traits similar … to dogs and chimpanzees.” For example, pigs:

·         have excellent long-term memories;

·         are whizzes with mazes and other tests requiring location of desired objects;

·         can comprehend a simple symbolic language and can learn complex combinations of symbols for actions and objects;

·         love to play and engage in mock fighting with each other, similar to play in dogs and other mammals;

·         live in complex social communities where they keep track of individuals and learn from one another;

·         cooperate with one another and show signs of Machiavellian intelligence such as perspective-taking and tactical deception;

·         can manipulate a joystick to move an on-screen cursor, a capacity they share with chimpanzees;

·         can use a mirror to find hidden food;

·         exhibit a form of empathy when witnessing the same emotion in another individual.

“We have shown that pigs share a number of cognitive capacities with other highly intelligent species such as dogs, chimpanzees, elephants, dolphins, and even humans. There is good scientific evidence to suggest we need to rethink our overall relationship to them,” according to Marino   

Upcoming in the open access journal International Journal of Comparative Psychology (no DOI yet). Top image: treehouse1977