Don’t judge the brain of the Paper Wasp by its size. Their brains are less than a millionth the size of human brains; but they have evolved face-learning abilities just like humans even though the two brains are structured very differently.
In a 2008 study, paper wasps were found to recognize individuals of their species by variations in their facial markings and that they are more aggressive toward wasps with faces they do not know. They found that these wasps have long memories and base their behavior on what they remember of previous social interactions. Sort of like us seeing someone and remembering that they are a jerk or a nice guy. Or, I know that guy, he stole my wallet.
In the latest study by the same University of Michigan evolutionary biologist, wasps were trained to discriminate between two different images mounted in a T-maze. One image was displayed at each end of T. Twelve wasps were trained for 40 trials on each image. The paired images included photos of normal paper wasp faces, caterpillars, geometric patterns, and computer-altered wasp faces. A reward was always associated with one image.
The paper wasps learned to pick the correct unaltered wasp face about three-quarters of the time. Also interesting is that minor alterations such as removing a wasp’s antennae caused the subjects to perform much worse on facial recognition.
The ability to recognize individuals is important since queens establish communal nests and raise offspring cooperatively, but there is also a dominance hierarchy to consider. It helps to remember who you rank above and who you rank below. It also helps so that energy is not wasted on repeated aggressive encounters and likely enables the colony to run much more smoothly.