Signalling Theory is about different ways of sending messages. People use body language, such as facial expressions and hand gestures, to communicate. They also use words, symbols, and objects to show someone what they are thinking or feeling. For example, if someone raises their eyebrows, it could mean surprise or confusion. Or if someone gives you a thumbs up, it could mean they like what you said. These different signals help people understand each other without speaking or writing. Signalling Theory is a theory that looks at how different messages can be used to share information.