Chimp and bonobo infants
Chapter 12 endnote 21, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:
Chimps in language experiments were removed from their mothers in infancy and raised in a human-like environment vastly different from their natural habitat. These infants would normally live with their mother for up to ten years and nurse with them for five, so this premature separation could have changed the wiring of each chimp’s interoceptive network and strongly influenced the results of the experiments.
Chimp and bonobo infants are usually in continuous physical contact with their mothers, 24 hours a day, until they are three month old; a mother embraces her infant while the infant clings to her. In contrast, human infants have more physical separation from their mothers right after birth, and use vocalizations (cries, for example) to communicate.[1] This difference between human and non-human ape infants is important, and was largely overlooked by researchers who attempted to teach language to chimps and bonobos. Its easy to speculate that scientists assumed that it was OK to separate mother and infant at an early age, as long the baby received attentive, human-style caregiving. But chimp and bonobo infants expect different attachment behaviors when compared to human infants. The results of language-learning experiments may have been influenced by attachment problems in those infants,[2] a hazard that results from viewing other animals through the lens of our own conceit (i.e., as slightly inferior versions of the human species).