First, the span of absolute judgment and the span of immediate memory impose severe limitations on the amount of information that we are able to receive, process, and remember. By organizing the stimulus input simultaneously into several dimensions and successively into a sequence or chunks, we manage to break (or at least stretch) this informational bottleneck. Second, the process of recoding is a very important one in human psychology and deserves much more explicit attention than it has received. In particular, the kind of linguistic recoding that people do seems to me to be the very lifeblood of the thought processes. Recoding procedures are a constant concern to clinicians, social psychologists, linguists, and anthropologists and yet, probably because recoding is less accessible to experimental manipulation than nonsense syllables or T mazes, the traditional experimental psychologist has contributed little or nothing to their analysis. Nevertheless, experimental techniques can be used, methods of recoding can be specified, behavioral indicants can be found. And I anticipate that we will find a very orderly set of relations describing what now seems an uncharted wilderness of individual differences. Third, the concepts and measures provided by the theory of information provide a quantitative way of getting at some of these questions. The theory provides us with a yardstick for calibrating our stimulus materials and for measuring the performance of our subjects. In the interests of communication I have suppressed the technical details of information measurement and have tried to express the ideas in more familiar terms; I hope this paraphrase will not lead you to think they are not useful in research. Informational concepts have already proved valuable in the study of discrimination and of language; they promise a great deal in the study of learning and memory; and it has even been proposed that they can be useful in the study of concept formation. A lot of questions that seemed fruitless twenty or thirty years ago may now be worth another look. In fact, I feel that my story here must stop just as it begins to get really interesting. And finally, what about the magical number seven? What about the seven wonders of the world, the seven seas, the seven deadly sins, the seven daughters of Atlas in the Pleiades, the seven ages of man, the seven levels of hell, the seven primary colors, the seven notes of the musical scale, and the seven days of the week? What about the seven-point rating scale, the seven categories for absolute judgment, the seven objects in the span of attention, and the seven digits in the span of immediate memory? For the present I propose to withhold judgment. Perhaps there is something deep and profound behind all these sevens, something just calling out for us to discover it. But I suspect that it is only a pernicious, Pythagorean coincidence.

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

/pdf/the-magical-number-seven-plus-or-minus-two-some-limits-on-2xg878b7si.pdf

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

Techniques for partitioning objects into optimally homogeneous groups on the basis of empirical measures of similarity among those objects have received increasing attention in several different fields. This paper develops a useful correspondence between any hierarchical system of such clusters, and a particular type of distance measure. The correspondence gives rise to two methods of clustering that are computationally rapid and invariant under monotonic transformations of the data. In an explicitly defined sense, one method forms clusters that are optimally “connected,” while the other forms clusters that are optimally “compact.”

Hierarchical clustering schemes

The information available in brief visual presentations.

Nearly perfect speech recognition was observed under conditions of greatly reduced spectral information. Temporal envelopes of speech were extracted from broad frequency bands and were used to modulate noises of the same bandwidths. This manipulation preserved temporal envelope cues in each band but restricted the listener to severely degraded information on the distribution of spectral energy. The identification of consonants, vowels, and words in simple sentences improved markedly as the number of bands increased; high speech recognition performance was obtained with only three bands of modulated noise. Thus, the presentation of a dynamic temporal pattern in only a few broad spectral regions is sufficient for the recognition of speech.

/pdf/speech-recognition-with-primarily-temporal-cues-121lmvokkq.pdf

Speech recognition with primarily temporal cues.

Sixteen English consonants were spoken over voice communication systems with frequency distortion and with random masking noise. The listeners were forced to guess at every sound and a count was made of all the different errors that resulted when one sound was confused with another. With noise or low‐pass filtering the confusions fall into consistent patterns, but with high‐pass filtering the errors are scattered quite randomly. An articulatory analysis of these 16 consonants provides a system of five articulatory features or “dimensions” that serve to characterize and distinguish the different phonemes: voicing, nasality, affrication, duration, and place of articulation. The data indicate that voicing and nasality are little affected and that place is severely affected by low‐pass and noisy systems. The indications are that the perception of any one of these five features is relatively independent of the perception of the others, so that it is as if five separate, simple channels were involved rather than a single complex channel.

An analysis of perceptual confusions among some English consonants.

Erratum: An Analysis of Perceptual Confusions Among Some English Consonants [J. Acoust. Soc. Am. 27, 339 (1955)]

Some effects of unequal spatial distribution on the detectability of radar targets.

The English consonants p, t, k, f, θ (thin), s, ∫ (she), b, d, g, v, ð (they), z, ȝ (beige), m and n were pronounced before the vowel a (father) by female talkers with General American pronunciation. Listeners heard the syllables in the presence of a masking noise and were forced to guess at every syllable. The signal‐to‐noise ratio, measured between the over‐all level of the noise in a band from 20 to 7000 cps and the level of the vowel as read on a VU meter, ranged from −18 to +12 db in steps of 6 db. Five talkers were used with four listeners for each talker. The most obvious aspect of these consonants in noise is the presence or absence of voicing; voiced and voiceless consonants were seldom confused until S/N was about −12 db or worse. The aspect of nasality also seems to disappear at about −12 db. The next most obvious aspect is the difference between stops and continuants; confusions on this aspect did not occur until S/N was about −6 db or worse. These three aspects define five classes of consonan...

Patricia E. Nicely

Papers

An analysis of perceptual confusions among some English consonants.

Erratum: An Analysis of Perceptual Confusions Among Some English Consonants [J. Acoust. Soc. Am. 27, 339 (1955)]

Some effects of unequal spatial distribution on the detectability of radar targets.

An Analysis of the Confusion among English Consonants Heard in the Presence of Random Noise