The Effect of Stimulus and Task Variables on Response Times to Pictures and Words

Visual display terminals VDTs are one of the most important man- machine interfaces in many modern military combat systems, such as sonar and fire-control systems aboard submarines. The complexity of these systems, both in terms of the technological sophistication of the equipment involved and in terms of the problem domain itself, usually results in an overwhelming amount of information being provided to the system operator via VDTs and other interfaces. The provided to the sheer amount of information that must be processed, coupled with frequent time constraints, dictate that operators be able to read and interpret the visual symbols representing information on the VDTs as efficiently as possible. There are many different kinds of visual symbols used on visual displays, including written words, alphabetic abbreviations, numerals, graphic symbols, and pictographs. In some cases, the same information can be depicted by more than one type of symbol or representation, such as a picture and its written word label to represent and object such as a submarine. If there are differences between different kinds of symbols, in how efficiently they can be processed by operators, then it makes good sense to use those kinds that are most efficiently processed if designers are free to choose among more than one kind of symbol for representation of certain information.