The magical number seven, plus or minus two: Some limits on our capacity for processing information.

Finished · Cognitive Science

Summary

This article is really well done. It discusses the basic channel capacity (ability to discriminate different categories) of humans based on various modalities and number of dimensions. On one dimensional lines, we have relatively small capacity to distinguish categories (about 7). As the number of dimensions that are different increases, our ability to distinguish categories rapidly increases (up to the thousands likely). This is why the phonetic dimensions of which phonemes differ from one another is not unidimensional. The multiple dimensions of variation allow for increased capacity to distinguish categories.

An additional, and awesome, component of the paper is the short term memory capacity. Miller reviews various experiments and shows that the sequential memory capacity is about 7 units long. After that, it is difficult to remember. However, if we "chunk" units into larger bins, we can still remember about 7 units long, despite the added bits required.

Evaluation

I think this is a pretty great explanation for WHY abstract structure emerges from and becomes stabilized as categories above the input signal...it increases our memory capacity. Chunking a continuous signal into symbols, chunking those symbols into syllables, those syllables into feet, those feet into phrases, maximizes human memory abilities. The question of why the same structures emerge again and again, is the central question linguists ask in the search and explanation of universals.