Question

What is an interaction style and what is its role in effective interface design? List and briefly describe any two advantages and disadvantages of each interaction style.

Answer 1

Interaction style is a way in which humans interact with a computer interface. Each interaction style effects the overall efficiency and usability of the computer system, but that is not to say there are good or bad interaction styles. The styles all have benefits and trade offs when dealing with certain types of users and it is often in an interface designers best interest to use a combination of styles instead of anyone one style alone.

Visual representation

Visual representation (also known as Direct Manipulation) features a natural representation of task objects and actions. This helps present the process as actually performing a task itself directly even though it is being doing through an intermediary like a computer. The visual representation usually takes the form of a metaphor related to the actual task being performed. In this way well designed visual representation systems tend to make the interaction enjoyable for the users, which is excellent for novice users or complex tasks that can lead to anxiety.

Advantages

• Visual presentation of task concepts
• Allows easy learning

- Disadvantages

• Can be hard to implement
• Requires graphics display/pointing devices

Menus

Menus provide a way to visually organise a very large set of actions. Menus are nearly ubiquitous in modern applications, with the most standard format being the "File/Edit" style strip located across the top of windows (such as in Microsoft Windows) or the user's workspace (such as in Multiple Document Interfaces, or in Mac OS X). Menus do not have any obvious physical metaphor, and rely on users being able to tell the difference between an action, and a category which can be expanded into a child set of actions and/or further categories. Menus can also change depending on context, from enabling or disabling individual items depending on the program's state, to using "tabbed toolbars" to flip between item collections.

+ Advantages

• Accessible to novice and intermittent users
• Allows for a very large palette of structured commands which can be easily "explored"

- Disadvantages

• Can bury useful features under complex hierarchies
• Number of items limited by screen resolution

Command Line

Command line is the earliest used interaction style and is still seen predominantly in Unix operating systems though still usable to varying degrees on Windows and OSX. This style is mainly used by expert users by typing into a prompt that allows them to quickly execute commands. Unfortunately command line places a considerable burden on the user to learn and recall commands from memory. It is often the case that commands take parameters as well and most of the added benefits (mainly in the way of efficiency) come from using them. This leads to an unfriendly environment for both novice and intermediate users that may attempt to use this style.

- Advantages

• quick and powerful for experienced users
• user-controlled interaction

- Disadvantages

• little or no prompting
• requires user’s knowledge of system, programs

Natural Language

Natural Language is an interaction style which allows the user to communicate with their computer through a series of spoken commands, similar to how one may issue spoken commands to another person. However the benefits and applicability of Natural Language systems thus far is very limited, largely due to the imprecise and verbose nature of spoken languages. A major issue with using spoken language is that to communicate with computer systems the vocabulary would need to be limited to a specific subset of a full natural language, in order to both reduce ambiguity and keep processing time within reasonable bounds. One solution to the ambiguity of spoken languages is to utilize gestural language, which is considered at least as natural as verbal language. At the same time, the definition of what makes a natural language is very important. It is not as though humans are born knowing spoken word or gestures; a natural language is simply one which can be grasped fluently by the time one is required to draw upon it.

+ Advantages

• Allows users to communicate with their system naturally
• Can reduce or eliminate the need for keyboards, great for those with poor keyboard skills

- Disadvantages

• Currently cannot accurately interpret much of verbal language, which is too ambiguous
• Requires a lot of training for each user so it can interpret their verbal commands