A dog may be man’s best friend, but can dogs join in on a joke by laughing? If so, what does this suggest for animal behavior and their cognitive skills? New research suggests that animals not only have the ability to respond to physically-induced sensory stimulation that causes laughter, but that certain behaviors may trigger cognitive reactions that strongly resemble human laughter as well. If so, it is hard to say who has the last laugh: animals or us.
From Birth to Mirth
For many years, scientists have studied chimpanzees, gorillas and other primates, as well as rats and even dogs to develop theories regarding the evolution of animal pleasure and mirthful behavior. Interestingly, two categories have emerged from such studies that shed more light on whether animal laughter is merely a reactionary or cognitive response.
•Reactive Laughing- Scientists have long studied chimpanzees, gorillas and others in the primate species in order to identify evolutionary traits and common ancestry links. Through their research, scientists have discovered that when chimpanzees, orangutans and gorillas wrestle or are tickled, they exhibit laughter-like vocalizations. Whether or not the animal lives in the wild or exists in captivity doesn’t matter; a spontaneous game of tag produces the same result — laughter.
While chimpanzee laughter may not sound like human laughter, it does follow the same spectrographic pattern that human babies follow. That is, they alternate between rapid inhalations and exhalations, create similar facial expressions and even share similar ticklish areas on the body such as the armpits and belly. Unlike humans, however, chimpanzees continue to enjoy being tickled throughout their entire lifespan. There are few elderly among us humans who would admit the same.
•Cognitive Laughing- Likewise, rats also have striking similarities to humans when it comes to our funny bones. When tickled and/or engaged in physical activity and play, rats emit long, high frequency, ultrasonic, socially induced vocalized… well, laughter. Extensive studies by Jaak Panskepp and Jeff Burgdorf, then at Washington State University, concentrated on whether rats can become accustomed and conditioned to tickling sensation so as to seek it out on their own volition. The result is no laughing matter. Over time, not only do rats become conditioned to the tickling sensation but they seek out the tickler — thereby strongly suggesting a link between sensing the stimulus and acting upon the favorable positive emotion — a cognitive connection, to be sure.
Of additional interest, rats that “laughed” the most also played the most, and preferred to spend more time with other laughing rats. Just as humans abide by the old adage “like attracts like” so too do rats appear to socially prefer other rats who exhibit similar laughing behavior.
Obviously, it is hard to know what goes on in an animal’s brain, but ongoing research and analysis seem to suggest that laughter is not only a way to signal joy but also an age-old tool used to promote social bonding. With this in mind, it seems fair to say that animals may very well have the last laugh.