Things continue to exist even when we can’t see them, but until we’re old enough to understand that notion, it’s out of sight, out of mind. Object permanence is one of those things we figure out when we’re eight months to a year old. Now, according to new findings published in Applied Animal Behaviour Science, adorable dwarf goats understand object permanence too, Science reports.
Previous work revealed that animals such as dogs, cats, and primates have reached certain stages of object permanence development. But only primates have approached stage 6, the highest stage humans have. Other animals might find it difficult to follow once-hidden objects, especially when there are complex movements involved. They fall for what’s called A-not-B errors. For humans, that’s when a baby is able to successfully, and repeatedly, locate a toy that’s hidden in box A, but when it’s moved to box B, they still look for it in box A -- even when they watched it being moved.
To see if object permanence exists in these wee little ungulates, a German team led by Jan Langbein from the Leibniz Institute for Farm Animal Biology conducted a series of experiments with female Nigerian dwarf goats (Capra aegagrus hircus).
First, they wanted to see if dwarf goats committed the A-not-B error. The critters watched as a researcher hid a tasty piece of uncooked pasta beneath the same plastic cup several times. When the pasta was then hidden in full sight of the goats under an empty cup nearby, six out of nine goats successfully located it, Science reports. The dwarf goats showed only a small prevalence to commit the A-not-B error.
Then the team investigated the goats’ ability to track the movements of hidden objects in a crossed transposition task: The pasta reward was hidden in one of two hiding places (cups) as the goats watched, but then the researchers changed the locations of the cups to see if the goats could follow the baited one and choose it at the new position. In these tasks, the goats weren’t so successful if the two cups were identical. But they were pretty good at locating the pasta treat if the two cups had different colors or shapes.
These findings, they write, provide the first evidence that dwarf goats might be able to keep track of hidden objects that cross paths during transposition by encoding visual feature cues. Keeping track of that trajectory implies that these little goats have reached a higher stage of object permanence than any another nonprimate mammal, Science reports.