Science Cognitive Lecture: 4.14 Language Grammar A. "The relationship between form and meaning" B. Example 1: Verbal Morphology 1. 1st: Singular Amo ; Plural = Amamus C. Example 2: Embedded Clauses 1. A rat was chased by a snake sang 2. A rat chased a snake that sang II. Negotiating a Communication System A. Start with a population of agents that can 1. Manipulate internal representations 2. Produce and recognize signals 3. Learn from each other's behavior B. Agents express meanings with signals, and attempt to interpret signals sent by others C. A system emerges as agents alternate between: 1. Contributing to the system, by inventing signals to express meanings 2. Conforming to the system, by using observations of others to guide their subsequent behavior III. Networks for Communicating of Strings Symbols A. Character Input Input Layer Hidden Layer Output Layer Meaning Output B. To receive a string: 1. Process each symbol; 2. At the end of string, meaning = activations of output layer C. To send a meaning: 1. Determine symbol that minimizes net's output error with the meaning 2. Send that symbol 3. Process that symbol 4. If net's output is correct, quit 5. Else continue IV. Conclusions A. Relatively simple learning abilities can result in accurate systems for communicating complex meanings B. Syntactic regularities emerge as stable, learnable, and consistent conventions that both senders and receivers can employ C. The "learning dynamic" shapes properties of the systems --- without any encoding of those properties in the learning mechanism D. I.