Heuristics
Ordinary people in the real world think and operate within (what Simon (1957) described as) bounded rationality. Within such bounds, people use heuristics to "satisfice" - i.e. come to a solution that is "good enough" for their purposes (but may be non-optimal in many other ways).
Heuristics are "rules of thumb": simplifications, educated guesses, hunches-with-bells. They're used by ordinary people (all the time, every day, all their lives) during the course of thinking and reasoning about the world. Specifically, heurstics are used to limit or reduce the "search space" in difficult or poorly understood problem domains.
Unlike an algorithm - which is typically what a computer program implements - a heuristic does not guarantee an optimal (or even feasible) solution.
In HCI and usability, heuristics abound everywhere you look: naturally, since usability deals with real people, who use heuristics rather than algorithms all the time. A usability heuristic might be: "A system should always keep users informed about what is going on, through appropriate feedback within reasonable time."
Hover state
Hover state (contrasted with non-hover or off state) refers to the appearance (and behaviour) of a textual hyperlink or button on a web page when the user rests their mouse pointer over it. Typically, the hover state will differ graphically from a non-hover state (and the clicked or visited state). A common example is that of a textual hyperlink, which becomes underlined on hover (i.e. its hover state is underlined whereas its off state is non-underlined).
Human interface objects
In the context of software systems and websites, human-interface objects are persistent artefacts that appear in the user's environment, and typically include folders, documents, and the rubbish bin.
- Human-interface objects can be seen, heard, touched, or otherwise perceived
- Human interface objects that can be seen are quite familiar in graphic user interfaces. Objects that play to another sense such as hearing (i.e. auditory icons) or touch are less familiar
- Human-interface objects have a standard way of interacting
- Human-interface objects have standard resulting behaviours
- Human-interface objects should be understandable, self-consistent, and stable
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