The Effect of “Natural” Grouping of Numerals on Short Term Memory
Calvin E. Thorpe, George E. Rowland · Human Factors The Journal of the Human Factors and Ergonomics Society · 1965
When individuals undertake to memorize long sequences of items, they show a strong tendency to break the sequences into smaller subgroups. This type of spontaneous grouping can be called “natural” grouping. This report reveals that certain specific grouping patterns are spontaneously utilized significantly more often than others for various particular sequence lengths. Furthermore, those persons who employ these “natural” grouping patterns obtain significantly better recall results. The most “natural” subgroup size was found to be three digits with two digits being the next most “natural.” These findings should be useful for any application in which number codes are used (telephone numbers, license plates, stock numbers, etc.).