Domestic dogs also identify the round shape with the pseudo-word "Bouba" and the angular shape with the pseudo-word "Kiki": this is known as the "Bouba-Kiki effect," which has previously been observed in humans and chicks. The University of Parma conducted the study "Hearing Shapes: the Bouba-Kiki effect in adult domestic dogs," which was published in the journal "Proceedings of the Royal Society B: Biological Sciences". The study is part of a larger comparison project being conducted at the University of Padua that also includes chicks and children. Parma's study subjects were family-owned dogs. Seventy adult dogs were tested by showing them two images, one round and one angular, while listening alternately to "Bouba" or "Kiki". In 19 of the subjects included in Study 2, the owner wore headphones and could not hear which of the two words was being played, thereby controlling for a possible Clever Hans effect, i.e., the involuntary influence of the owner's cues. When the pseudo-word "Bouba" was played, dogs looked more toward the round shape, while when the pseudo-word "Kiki" was played, they looked more toward the angular shape. Furthermore, among the 51 subjects in Study 1, dogs had a faster first-look latency to the angular shape, regardless of the sound played, and explored the angular shape more when they heard the pseudo-word "Kiki". Overall, the findings suggest that dogs exhibit a spontaneous sound-shape association consistent with the Bouba-Kiki effect. This gives credibility to the theory that this effect is part of a larger set of cross-modal correspondences shared by several animals, rather than being a uniquely human trait that is only dependent on language. Dogs have previously demonstrated similar connections, such as associating higher-pitched noises with smaller body size and lower-pitched sounds with greater body size, and responding differentially to congruent or incongruent combinations of auditory and visual elements. Another particularly intriguing subject is whether phonetic symbolism influences how dogs process human voices, learn language, and perceive orders.