SAGE Publications

Although it is generally believed that the representational characteristics of verbal stimuli (typescript or speaker's voice, for example) persist for a very brief time in sensory memory, some recent studies suggest that such characteristics may persist much longer. The present experiments show that words are recognized faster and more accurately when they are re-presented in the same voice. This same-voice facilitation did not decline over a 2-min lag. Further experiments showed that subjects could recall the voice in which a word had been presented with 65–75% accuracy after 2 min and 31 intervening items. It is concluded that, in some circumstances, the physical features of verbal stimuli persist in memory for several minutes.

A young woman, blinded by the development of corneal opacity at the age of 3 years, was given a corneal graft at the age of 27. Though the image-forming powers of the eye were largely restored, the patient showed little recovery of functional vision. Six months after operation she could detect and locate conspicuous objects and had some degree of ambient spatial vision but she could not learn to recognize simple visual patterns. Eventually she reverted to the life of a blind person. Her failure to recover is discussed in terms of the known deleterious effects of restricted early visual experience on the development of the visual cortex in animals.

Past research has proved equivocal in providing a correlation between the amplitude of cortical evoked potentials and attended or unattended stimuli. The present experiment is a further investigation of the relationship between selective attention and the cortical evoked potentials and avoids some methodological artifacts. The results of the experiment provide no direct support for the postulated correlation between the two variables, but do suggest two possible explanations of this state of affairs.

Three experiments are reported involving the presentation of lists of either letters or digits for immediate serial recall. The main variable was the presence or absence of a suffix-prefix, an item (tick or cross) occurring at the end of the list which had to be copied before recall of the stimulus list. With auditory stimuli and an auditory suffix-prefix there was a large and selective increase in the number of errors on the last few serial positions—the typical “suffix effect”. The suffix effect was not found with auditory stimuli and a visual suffix-prefix nor with a visual stimulus and an auditory suffix-prefix. These results are interpreted as supporting a model for short-term memory proposed by Crowder and Morton (1969) in which it is suggested that with serial recall information concerning the final items following auditory presentation has a different, precategorical, origin from that concerning other items.

The sampling (partial report) technique of Sperling (1960) was used to study the efficiency of selection of letters from visual immediate memory (sensory storage). Selection by location, chromatic colour, achromatic colour, and size was fairly efficient whereas selection by orientation was difficult. Some parallels between selection in visual immediate memory and selective listening are briefly discussed.

The effects of changing the number of choices in the first response on “psychological refractoriness” were found to be partially consistent with intermittency theory but modifications may be needed to explain the results when the number of choices in the second response is increased.

Groups of digits were presented binaurally and dichotically to subjects who were asked to recall them. Different rates and patterns of presentation were used, the design being based on that of Broadbent (1954). Broadbent's findings in this field were confirmed. If subjects are presented with simultaneous pairs of digits at a rate of 2 pairs per second dichotically, they cannot recall them if they are asked to alternate between the ears. If however the presentation is staggered, so that although the rate is constant the signals do not overlap, subjects can recall alternately from the two ears. It is suggested that these findings are better interpreted as an interference effect, not a rate effect. Criticism is offered of similar designs to measure “switching rate”. Criticism is also offered of Broadbent's estimate of “perception time” in such experiments. An analysis of the quantity and type of errors made by subjects is given, which suggests that Broad-bent's theory of a short term store on the peripheral side of a selective filter is in need of revision.

Subjects were asked to recall lists of digits presented either alternately to right and left ears or successively to both. Performance was worse with alternating than with successive lists and the decrement was greater with the faster presentation rate. However, there was no interaction between type of presentation and either digit length or list length. The latter finding suggests that the effect arises in perception rather than in memory and is consistent with the idea that it takes time to shift attention or reset the parameters for perceptual processing of alternating monaural speech items.

The three experiments described in this paper were intended to show whether voluntary attention to a particular part of the peripheral visual field had any effect on the accuracy of the subject's perception. Test objects near to threshold value (for acuity or for changes in luminance) were used. The experiments were also designed to study the possible distracting effect of other stimuli presented simultaneously in different parts of the field.

In Experiment 1 the subject could be given foreknowledge of the position in which an acuity test object would appear. In Experiment 2 the signal of where to attend was given simultaneously with the exposure of an acuity test object. In Experiment 3 differential thresholds for luminance were investigated by methods similar to those used in Experiment 2.

It was found in all these cases that the instructions to attend to a particular part of the peripheral field had no significant effect on perception unless there were simultaneously exposed “competing” stimuli in other parts of the field. The results support the view that, in peripheral vision, attention acts selectively on the immediate memory trace only when there is a complex pattern of stimulation.