Donald E. Broadbent

On the relationship between task performance and associated verbalizable knowledge

Three experiments explore the relationship between performance on a cognitive task and the explicit or reportable knowledge associated with that performance (assessed here by written post-task questionnaire). They examine how this relationship is affected by task experience, verbal instruction and concurrent verbalization. It is shown that practice significantly improves ability to control semi-complex computer-implemented systems but has no effect on the ability to answer related questions. In contrast, verbal instruction significantly improves ability to answer questions but has no effect on control performance. Verbal instruction combined with concurrent verbalization does lead to a significant improvement in control scores. Verbalization alone, however, has no effect on task performance or question answering.

From detection to identification: Response to multiple targets in rapid serial visual presentation

In four experiments, words were presented visually at a high rate; as has been found previously, subjects could identify individual target words and must therefore have gathered some information even about the unreportable nontargets. The novel feature of this study was that there were frequently two targets in the list; the occurrence of the first target disrupted identification of the second for a subsequent period of more than half a second. This happened whether the target word was designated by a single physical feature or by the semantic characteristic of belonging to a specified category. The two situations did differ, however, in that unidentified targets of the first type still disturbed an accompanying second target, whereas those of the second type did not. The results are interpreted as meaning that a simple undemanding process of detection triggers other and more demanding processes of identification, so that the occurrence of the latter for one target interferes with their occurrence for another.

Information Conveyed by Vowels

Most speech sounds may be said to convey three kinds of information: linguistic information which enables the listener to identify the words that are being used; socio‐linguistic information, which enables him to appreciate something about the background of the speaker; and personal information which helps to identify the speaker. An experiment has been carried out which shows that the linguistic information conveyed by a vowel sound does not depend on the absolute values of its formant frequencies, but on the relationship between the formant frequencies for that vowel and the formant frequencies of other vowels pronounced by that speaker. Six versions of the sentence Please say what this word is were synthesized on a Parametric Artificial Talking device. Four test words of the form b‐(vowel)‐t were also synthesized. It is shown that the identification of the test word depends on the formant structure of the introductory sentence. Some psychological implications of this experiment are discussed, and hypot...

What makes interruptions disruptive? A study of length, similarity, and complexity

SummaryClassic work on interruptions by Zeigarnik showed that tasks that were interrupted were more likely to be recalled after a delay than tasks that were not interrupted. Much of the literature on interruptions has been devoted to examining this effect, although more recently interruptions have been used to choose between competing designs for interfaces to complex devices. However, none of this work looks at what makes some interruptions disruptive and some not. This series of experiments uses a novel computer-based adventure-game methodology to investigate the effects of the length of the interruption, the similarity of the interruption to the main task, and the complexity of processing demanded by the interruption. It is concluded that subjects make use of some form of non-articulatory memory which is not affected by the length of the interruption. It is affected by processing similar material however, and by a complex mentalarithmetic task which makes large demands on working memory.

Two modes of learning for interactive tasks.

Abstract This paper argues that human cognition employs two modes of learning, s-mode and u-mode. S-mode learning takes place by means of abstract working memory and is delective and reportable. U-mode learning occurs outside abstract working memory and is unselective and unavailable for verbal report. Three experiments are described, employing two tasks which have previously been shown to give rise to two modes of learning consistent with the conceptualisations of s-mode and u-mode learning. The experiments explore the effects of introducing a secondary verbal task on learning, performing and relearning these tasks. The secondary task can be expected to interfere with s-mode learning. It was found that adding the secondary task interfered with performing and relearning one of the tasks, the one for which subjects could verbalise what they had learnt. In contrast, for the other task, for which subjects could not verbalise their learning, performance and relearning were facilitated by adding the secondary task. These data argue for two modes of learning, only one of which involves the verbal system.

Anxiety and Attentional Bias: State and Trait

Abstract MacLeod, Mathews, and Tata (1986) found that anxious patients showed a tendency to react faster to a probe stimulus that appeared in the location of a threatening visual word rather than in that of a simultaneous neutral word. In 4 experiments, a total of 104 subjects drawn from the general population were tested on different variations of this task. A relationship to anxiety was confirmed, and it was shown that this relationship did not appear on animal names that also formed a semantically similar set and had an equal probability of being followed by a probe stimulus. Although the effect is therefore dependent on the content of the word, it builds up during the experimental session and is therefore likely to be due to increasing post-attentive awareness of the presence of threatening words. The most reliable results across experiments were found by using Trait rather than State Anxiety, and particularly by fitting a curvilinear relationship such that the exact degree of Anxiety makes little dif...

Levels, hierarchies, and the locus of control

The Bartlett—Craik view of human performance is restated; and particularly that it is organised at different levels. On that view, the lower levels are controlled by the upper but capable of functioning independently. Modern views of memory, language, and problem-solving are compared with this doctrine, and found to embody some of its virtues but not all. Fresh experiments are described, in which people take decisions about the running of a transportation system. The simplest control mechanism which will model their behaviour is a two-level adaptive controller.

Successive responses to simultaneous stimuli

Previous work had shown that, when a memory-span experiment is performed with half the items presented to one ear, and half simultaneously to the other, a certain order of response appears. Either one ear or the other is dealt with first, and then the remaining items produce a response afterwards. The present results extend this finding to the eye and the ear rather than the two ears, and also to two voices distinguished by their frequency characteristics. For the latter condition, it is also shown that alternation of attention can take place at a speed faster than between the two ears. The effect thus appears to be a general one, and not merely a peculiarity of binaural hearing.

The Maltese cross: A new simplistic model for memory

This paper puts forward a general framework for thought about human information processing. It is intended to avoid some of the problems of pipeline or stage models of function. At the same time it avoids the snare of supposing a welter of indefinitely many separate processes. The approach is not particularly original, but rather represents the common elements or presuppositions in a number of modern theories. These presuppositions are not usually explicit, however, and making them so reduces the danger of slipping back into earlier modes of thought.The key point is to distinguish between persisting representations and the processes that translate one representation into another. Various classes or groups of persisting representations can be distinguished by the experimental treatments that interfere with them. In particular, there now seem to be several kinds of short-term or temporary storage, different from each other as well as from longterm memory; the translating processes also have several different modes or kinds. A particularly important aspect of the current position is that a model of this general type no longer requires some external agent to direct and control long sequences of behaviour.

On the Fusion of Sounds Reaching Different Sense Organs

A simple place theory of hearing raises the problem that several mixed harmonics may be attributed by the listener to their appropriate fundamental frequencies: the recognition of a vowel sound in the presence of other sounds requires that the formants of the vowel be detected as such and not classified with the other sounds. Thus, the neural message from a particular part of the basilar membrane probably conveys in some way information on the fundamental frequency, to a harmonic of which that part of the membrane is responding. The problem of fusion of sounds on the two ears is merely an extension of the problem of fusion of different frequencies in one ear.It is shown that synthetically produced speech will fuse when the first formant is presented to one ear and the second to the other, but it will not do so if the formants are given different fundamental frequencies. Even when both formants are given to the same ear, the latter condition fails to fuse. A further experiment with sustained formants shows...