#easyNet demo ##The gang effect The explanation of the the difference between **move** and **mate** has to do with top-down feedback from the word layer to the letter layer. This feedback causes **have** node sends an excitatory signal to the **H** node in position one, the **A** node in position two, the **V** node in position three and the **E** node in position four. The net effect of this top-down feedback will depend on which clusters of nodes are active at the word level. There are many words that end in **AVE** or are of the form **MA?E** (e.g., **made**, **make**, **male**, **mane**, **mare**, **mate**, **maze**). By contrast, there are relatively few words that end with **OVE** or are of the form **MO?E** (apart from **move**, the only other word of this form in the model’s vocabulary is **mole**). Consequently, the top-down feedback to the **A** node in position two will be much greater than the feedback to the **O** node in position two, and hence the **A** node will be more strongly activated. That is, **move** and **mate** will not receive equivalent feedforward input from the letter layer. Furthermore, the resonance between the letter and word layers means that the greater activity of the **A** node will in turn further boost the advantage of words like **have** and **make** over the word **move**, and this in turn will further amplify the differences at the letter layer. McClelland and Rumelhart refer to this as the **gang effect**. It is another good example of non-linear feedback processes within the model. [[start|Back to Index]]