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Models of sensory storage appear to incorporate three features: capacity in excess of short-term memory, rapid decay of information, and an unprocessed trace as the storage medium. The evidence for each is examined in the visual and the auditory modes. The excess capacity hypothesis is rejected on the grounds that negative results are obtained when output interference and cue anticipation mechanisms are excluded. Rapid decay is seen as a minor effect which may not result from sensory storage. Limited trace storage appears to exist in the form of extremely brief sensory persistence, but applies only to normally attended stimuli; the pivotal concept of subsequent random access to a trace appears unsupported. [ABSTRACT FROM AUTHOR]

Ss either saw or heard lists of three syllables which differed by their initial consonant phoneme or their final vowel phoneme. After 5 or 15 sec of mental arithmetic, Ss were required to recall the syllables. Following auditory presentation, vowels were recalled more accurately than consonants in all serial positions and at both delays. In addition, spoken consonants and vowels showed primacy and recency effects. Following visual presentation, consonants and vowels were recalled with equal accuracy at both delays, and no recency effects were observed. These data suggest that superior recall of vowels over consonants results from differential decay of these stimuli in an acoustic storage. These data are consistent with previous experiments showing that, during serial recall, the final vowels in a sequence are recalled more accurately than the final consonants. [ABSTRACT FROM AUTHOR]

Listeners quickly learn to identify, apparently on an absolute basis, the ordering of a pair of sounds, where one sound is a specific random selection which is constant over successive observations, and where the other sound varies over successive observations. The accuracy of identification is not directly related to the uncertainty of the pool of possible waveforms. A wide range of sample durations and spectra characterize the identifiable pools. Increasing the predictability of the sequences does not improve identification accuracy. Listeners also can identify one of two selections from the same pool and can identify departures from a prototype which they have never heard. Since all random selections from the same pool have nearly identical long-term average spectra, it is concluded that the listener must perform a short-term, or running, spectrum analysis upon the signals. Subject Classification: 65.22, 65.75, 65.68. [ABSTRACT FROM AUTHOR]

Backward recognition masking refers to the interference of a second sound on recognition of another sound presented earlier in time. Previous experiments have demonstrated backward recognition masking in an absolute judgment task. In those experiments, all of the experimental conditions were varied randomly within a test session. In the first experiment reported here, backward-masking functions generated between blocks of trials were compared to those determined within an experimental session. The results showed backward masking using both experimental procedures. The next two experiments evaluate backward-masking effects in a two-interval forced-choice task and a successive-comparison task. Backward masking was observed in both experiments. The final experiment showed that selectively attending to the ear of the test tone presentation does not attenuate the backward-masking effects of a second tone presented to the opposite ear. Subject Classification: 65.22, 65.58, 65.75. [ABSTRACT FROM AUTHOR]

Dichotic CV syllables were presented at stimulus onset asynchronies (SOAs) between 0 and 480 msec in two ear-monitoring tasks (''forward'' and ''backward masking''). The design included indentical pairs and orthogonally varied stimulus intensities. A ''similarity effect'' (higher recognition scores when the target syllable contrasted on fewer features with the ''masking'' syllable) was found over the whole masking range (ca. 300 msec). Other findings included strong effects of both target and mask intensities, a ''lag effect'' but no right-ear advantage, and generally opposite effects on identical and nonidentical pairs. Identical pairs showed no masking at all. A model is suggested to account for the pattern of errors in dichotic listening: confusions are assumed to arise from nonspecific capacity limitations (''perceptual noise''), separately for each stimulus (hemisphere), and, at short SOAs, responses are assumed to be frequently assigned to the wrong channel. In addition, fusion may occur at very short SOAs. It is further argued that little direct interaction between dichotic inputs may take place; that central convergence occurs at a late stage in processing; that the assumption of a feature processing stage as distinct from a phoneme recognition stage may be unnecessary; and that the backward ''masking'' range cannot be equated with absolute processing time. Subject Classification: 70.30. [ABSTRACT FROM AUTHOR]

Subjects adjusted the rate of a binaural pulse train so that it matched the perceived rate of a dichotically alternated pulse train, in which successive pulses were heard in the left and right ears alternately. At low rates, subjects matched the total rate of pulses-into-the-head. At high rates, they matched the rate of pulses in one of their ears. The crossover was quite sharp, and took place when the interpulse interval in one ear was about 100-200 msec. The results are discussed in relation to results with alternated and temporally segmented speech, and to acoustic short-term memory. [ABSTRACT FROM AUTHOR]

Weak lead stimulation can modify the human startle reflex. It is proposed that, with the aid of physiological measures taken in the interval between lend and startle stimuli, this paradigm offers a promising method of Investigating different levels of central processing, the operation of a short time-constant as opposed to a long time-constant stem, and the operation of an orienting-attentional as opposed loan intensity-dependent activational system. [ABSTRACT FROM AUTHOR]

The article focuses on pattern recognition applications in the biometrical science. Physicists were among the very first to feel the need of automatic analysis of photographic images, for several years physicists had found themselves faced with an increasing number of photographs of bubble-chambers and spark-chambers to examine. When the possibilities of manually processing such a quantity of photographic data become insufficient, pattern recognition ceased to be the problem of basic research in the artificial intelligence field that it had been up to the fifties and became above all an applied research aiming at the realization of automatic recognition systems for particular images. The definition of the neurophysiological processes of perception and pattern recognition represents a not yet solved problem. The coming of electronic systems of transmission and processing of data has also supplied the subject of pattern recognition with new methods of studying, suggesting the designing of machines capable of carrying out operations of recognition as replies to a series of stimuli; that is, working in a similar way to the human brain.