Preliminary experiments on keyboard design for semiautomatic mail sorting.

Mail sorting by keyboards will require operatives either to remember digitation for each address (memory encoding) or key certain selected characters from the address (extraction encoding). Keyboards may be chord (multiple depressions per stroke) or sequential (single keys in succession), 3 preliminary experiments indicated (a) in sequential keying a key stroke takes approximately 0.3 sec., hence keyboards with many keys and requiring few key strokes per encoding are preferable; (b) for memory encoding a chord keyboard with many keys (24) is superior to a smaller chord keyboard and a sequential keyboard, (c) for extraction encoding a typewriter and a 24-key chord keyboard are equal in performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)