Final answer:
Complex gesture systems refer to the use of symbolic gestures and body language to communicate, similar to those taught to great apes in studies suggesting an innate capacity for protolanguage. Human nonverbal communication is culturally dependent and can serve as an essential aspect of communication. Gesture-based systems possibly contributed to the evolution of spoken language.
Step-by-step explanation:
The question concerns the concept of complex gesture systems and their use in communication, specifically those that are not based on any specific spoken language. Humans have long studied nonhuman primates like chimpanzees, gorillas, bonobos, and orangutans, attempting to teach them gesture-based communication or use tokens to refer to objects, combined in rule-based ways to express wants or comment on their environment. This suggests that these animals might possess an innate capacity for something akin to a protolanguage, an elementary form of language based on gestures or utterances believed to have preceded human spoken language. In humans, nonverbal communication is rich and varied, used to convey emotions, intentions, and messages without words. Gestures and body language play an important role in this, acting as cultural symbols that can convey meanings which may be universal or culture-specific. For example, while smiles might generally be associated with happiness, a thumbs-up gesture carries positive connotations in some cultures, whereas it could be considered offensive in countries like Russia and Australia. Considering the evolution of language, researchers have hypothesized that gesture-based communication systems might have been pivotal in paving the way for the development of spoken language in early hominins. The human language is also distinctly 'open-ended', allowing for infinite combinations to communicate new meanings, a feature that differentiates it from animal communication systems, which are often more limited or 'closed'.