But there is a lot interaction design going with physical interfaces, not to mention the digital interfaces with physical inputs or digital inputs that control physical actions, so limiting it to “on the glass” is not quite right. It goes beyond the GUI. Part of the issue is that interaction design is a task that is associated with the design of anything, and industrial designers practice interaction design every day.
I completely agree here with Yo. Interaction Design is quite broad indeed and shouldn´t be limited to display applications only.
Going back to the original question of this post, I guess you could say that Interaction Design deals with the way people (sub)consiously interact with products and services.
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