Series Of Tasks Research Articles

Rhythm and the timing of movement sequences

Many motor skills involve a sequence of movements phased over a period of time. The present study investigated the importance of rhythmic timing structures in the acquisition and control of a serial key-pressing task. Four groups of subjects received extensive practice on 9-element finger sequences varying in the form of the inherent temporal structure. Following a training period, the stability of the various timing patterns was examined by requiring subjects to perform the key-pressing task concurrently with a verbal memory task. The memory task involved reporting back a sequence of visually-presented words with a lag of one word. A comparison was made of performance on the two tasks under dual task and control (single task) conditions. The results suggested that “natural” rhythmic timing structures require less attention for production than “unnatural” temporal patterns. A breakdown of the temporal patterns into “within-group” and “between-group” intervals showed that patterns containing within-group intervals that related as 1:1 or 1:2 evidenced good stability under dual-task conditions. These results were taken as support for the suggestion by Fraisse (1946) that the perception and production of rhythms can be understood by an internal representation that allows only two distinct durations that relate as 1:2. Furthermore, it was suggested that relative timing may become an invariant property of motor program representation only in those instances in which the timing sequence completely fits the internal timing structure.

Discrete allocation of a linear resource according to a sum-of-products objective

The allocation of a linear resource according to the sum of the returns from independent activities is considered. The return from each activity is given by a product of concave and nondecreasing functions of a single allocation variable. The model can be used, for instance, to describe probabilities of success of several serial tasks, into which an activity is subdivided. An incremental algorithm is defined and conditions are given for the algorithm to generate an optimal solution; otherwise, the problem is solved by a two-step procedure involving the incremental maximization of the return corresponding to a single activity and the combination of the activities by dynamic programming. Examples are given of problems solvable and not solvable by the incremental algorithm.

Can young children integrate premises in transitivity and serial order tasks?

An analysis is presented of the relational information needed for premise integration in transitivity and simple serial order tasks. The tasks are divided into those where an ordering decision can be made by considering a single binary relation, and those where two binary relations must be considered. Four experiments are reported, the principal purpose of which is to manipulate the number of relations which must be considered in making decisions about the order of a small set of elements. In every test it was found that preschool children succeeded if decisions could be made by considering one relation, but failed if two relations had to be considered. Children over 5 almost always succeeded in both cases. It is concluded that preschool children cannot integrate relational premise information, and therefore cannot understand transitivity or serial order. This would impose limitations on their understanding of quantification and a number of other concepts. It is also suggested that the amount of information required to make a single decision may be an important factor determining cognitive complexity generally.

How normal and retarded individuals monitor and regulate speed and accuracy of responding in serial choice tasks.

These experiments investigate whether or not differences in the way that retarded and nonretarded individuals monitor and regulate speed and accuracy of responding contribute to the slower and more variable performance of retarded subjects on choice reaction time (RT) tasks. Rabbitt (1979, 1981) suggested that efficient choice RT performance is mediated by subjects tracking increasingly faster RT bands on successive trials until, by making and recognizing errors, they discover those very fast RT levels that should be avoided and those safe bands, just above typical error levels, that should be tracked. Experiments 1A and 1B established that most retarded subjects detect their errors as efficiently as nonretarded controls, a finding that excludes the possibility that retarded subjects do not monitor accuracy efficiently but achieve comparable levels of accuracy by consistently responding within very slow RT bands that minimize likelihood of errors. Experiment 2 showed that while a qualitatively similar trial-by-trial tracking mechanism mediates the performance of both groups, retarded subjects are less efficient at constraining RTs within very fast, but safe, bands. Increasing error probabilities at longer RTs suggest that momentary fluctuations in stimulus discriminability and/or attention are factors affecting RT variability in retarded subjects. The RT patterns for various sequences of correct responses initiated and terminated by errors suggest that the effective past experience (EPEX) guiding trial-by-trial RT adjustments of retarded subjects is short and inadequate, and it was argued that this can account for much of the remaining RT variability contributing to retarded-nonretarded differences. Not only does a short EPEX increase variability by giving rise to long error-free sequences of slower than average RT but also, when combined with occasional specified random fluctuations, it suggests why retarded subjects can achieve, but not sustain, RT levels maintained by nonretarded subjects.

A study of nonstrategic linguistic coding on visual recall of learning disabled readers.

Three experiments directly investigated Vellutino's (1977) verbal-deficit hypothesis, which suggests reading difficulties of learning disabled children are attributable to deficiencies in linguistic coding. Short-term retention was studied using random shapes to minimize effects of prior verbal learning. Adopting a probe-type serial memory task, normal and LD readers were compared on recall performance after pretraining of named and unnamed stimulus conditions. Recall was markedly better for normal subjects trained with names compared with the unnamed control condition, while disabled children demonstrated inferior recall on named compared with unnamed pretraining. Experiment 1 demonstrated that verbal encoding effects were stronger for normal and deaf subjects than for disabled, especially on primacy positions. Experiment 2 suggested children's (normal and disabled) idiosyncratic verbal coding did not facilitate recall compared with names provided by the experimenter. Experiment 3 suggested that names for random shapes, regardless of age, facilitated recall for normal but not for disabled readers. Verbal codes appeared particularly important in differentiating groups at primacy positions. Consistent in all three experiments, no difference was found in recall of unnamed shapes between normal and LD readers. These experiments suggest that primary reading deficits are related to integrative linguistic deficiencies and not to deficiencies of visual memory or rehearsal.

Structural factors in patterned finger tapping

The relationship between the internal representation and the performance of serial tasks is studied. An experiment is reported in which subjects tapped as fast as possible serial ‘finger patterns’: sequences of taps made with different fingers. The patterns are assumed to be represented internally as hierarchies of operations. The latencies between successive taps are predicted from a production model — the Tree Traversal interpreter — which specifies the necessary actions to produce the finger pattern from a hierarchical memory representation. It was found that varying the internal representation of one and the same sequence of taps affects the performance in a predictable way. The relation of the proposed model to general theories of complex motor behavior is discussed.

Verbal Short-Term Memory Encoding of Learning Disabled, Deaf, and Normal Readers

The present study investigated the hypothesis that nonstrategic verbal encoding abilities are deficient in learning disabled readers. Normal, deaf, and learning disabled children matched on chronological age, IQ, and sex were randomly assigned to named and unnamed stimulus pretraining conditions and compared on subsequent performance on a probe-type serial memory task. Although overt rehearsal was inhibited, strong primacy effects were found for both the named and the unnamed condition. The named condition was superior to the unnamed condition for both normal and deaf but not for learning disabled children. Results were interpreted to indicate a deficient verbal-visual integrative process in disabled children occurring prior to the application of mnemonic strategies.

Visual memory and stimulus repetition effects.

Recent investigations of memory for randomly configured patterns indicate that visual memory can involve distinct short-term and long-term components. The appearance of a visual recency effect that is confined to the last-presented item is believed to result from the active visualization of this item during the retention interval. Studies of the retention of familiar visual information have also suggested that the short-term effects observed are a result of active visualization. In a review of these studies, however, we argue that the effects obtained with familiar visual information are not necessarily a result of active visualization and, indeed, may not involve anything other than long-term visual memory. For example, Rabbitt and Vyas (1979) observed a visual recency effect in a serial choice reaction time task involving familiar information. That this recency effect was confined to the final item accords with the results obtained with unfamiliar visual information. However, this choice reaction time task did not require subjects to remember previous stimuli, so it is unlikely that they actively visualized them. With the case for a distinct short-term visual memory currently resting on the recency effect interpreted as reflecting a process of active visualization, this result is especially important. In the second part of the present paper, we report a series of experiments that provides an understanding of the visual recency effect in the serial choice reaction time task. We conclude from these studies that this effect is not due to visualization or to a visual trace either decaying or being overwritten by a succeeding stimulus.

Visual and semantic effects in a serial word classification task

Subjects were asked to decide as quickly as possible whether each of a series of items was one of the four target words, ‘dog’, ‘rat’, ‘boar’ and ‘mole’. The relationship of distractors to the targets was varied. Distractors which were of high visual similarity to the targets took longer to reject than those which were of lower visual similarity, and distractors which were semantically related to the targets took longer to reject than those which were unrelated. These effects were independent. There was no effect of familiarity, with non-animal distractors and pronounceable non-words rejected equally quickly. These results are qualitatively the same as those earlier found with faces (Bruce, 1979).

Intermittent Isolation in a Serial Anticipation Task

Summary Introductory student volunteers anticipated a 12-CVC series in which the 7th member was isolated on 0%, 25%, 50%, 75%, or 100% of the trials. The magnitude of the isolation effect proved to be a direct function of the frequency of occurrence of the isolating stimulus, supporting predictions based upon relative utility of cues of different reliability and also extending the notion of “degree of isolation” to include repetition frequency. The results also suggested that an intermittent cue of this sort may be more effective if it first appears following an initial exposure to the series and task conditions.

Wholistic and Analytic Stimulus Processing: The Development of Selective Perceptual Strategies

This experiment reports an investigation of the development of selective processing strategies as subjects become increasingly more practised at a serial self-paced RT task. It demonstrates the effect a preceding stimulus can have on the analysis of a current signal and the development of active analytic strategies in favour of passive wholistic processing, with practice. The stimuli used were letters with irrelevant visual noise dot patterns superimposed on them. The letter, or the dot pattern, or both, could be repeated on successive trials. Early in practice repetition of both stimulus components simultaneously produced short reponse latencies relative to repetition of the letter alone. The number of noise dots markedly affected RT. Late in practice, however, letter repetition RTs were small, irrespective of whether or not the noise dot pattern was repeated. Furthermore, the number of noise dots no longer had an effect on the RT to these stimulus transitions. The results suggest that subjects appear to be able to select relevant information to process as they become progressively more practised, even though there is evidence that they compare the current stimulus with an iconic representation of the immediately preceding one.

Actively Controlling Anticipation of Irregular Events

There have been no investigations as to how people respond to sequences of events which occur at brief, unpredictable intervals as in everyday life. Eleven young adults were practised at a two-choice, continuous, serial choice-response task in which intervals between each response and the onset of the next signal (RSIs) varied randomly from trial to trial. On half the trials in each of four conditions the RSI was 20 ms, and on the other trials 200, 400, 800 and 1600 ms respectively. Reaction times fell as RSIs increased from 20-200 ms but thereafter appeared to be unaffected by RSI duration. In the 20/200 and 20/400 ms RSI conditions RT was not affected by transitions between different RSIs but in the 20/800 and 20/1600 ms conditions RTs were faster when the longer RSI recurred on immediately successive trials than if the long RSI followed the short (20 ms) RSI. These results are discussed in terms of a control system model for the way in which subjects actively trade off between their internal performance limitations to optimally meet task demands.

Movement speed in children.

Two experiments were conducted to investigate movement speed in children of 6, 8, 10, and 12 yr of age. Different information loads were presented to the children on a serial task (Experiment 1), and on a discrete task (Experiment 2). On both tasks there was a linear relationship between movement time and information load. Reaction time was relatively unaffected by and increase in the difficulty of the required movement. By employing the formula, capacity = (Index of Difficulty) / (movement time), there was an increase in capacity by age with very little overlap between the ages. Strategies on the serial task were discussed and comparisons with adult subjects were made.

PSYCHOLOGY OF THE SCIENTIST: XLII. BELIEFS OF E. C. POULTON

In a recent paper, Poulton (1980) has discussed some of my own experimental work on noise and performance. He put forward the view that the results were due to acoustic information derived from the apparatus. This view has of course already been discussed extensively in the literature and repudiated by myself as vigorously as academic propriety allows (Broadbent, 1976, 1977, 1978). Poulton now suggests not merely that such. an artefact existed, but that I myself was aware of it and concealed it. Only two points need to be made in reply. First, readers of Perceptual and Motor Skills should be made aware that this matter is solely of personal or historical, and not of scientific, interest. In a paper published in Britain, Poulton (1978) has now accepted that the phenomena claimed in my own studies, and in those of Hockey, have also been obtained in later studies where Poulton himself agrees that no apparatus artefact can conceivably have been involved. That is, noise does produce reduced detection in vigilance measured with a risky criterion, does give the change in distribution of attention sometimes called 'funnel vision', and does give errors on a serial reaction task. Poulton attributes the first effect to changes in internal speech, and the second to increased arousal. The third he explains by the fall in arousal after the stage of increase, which causes inefficienq even if the noise is turned off. These theories are of course open to debate; but the key point is that rhe phenomena are in general not in dispute, merely my own original claim to have established them. Second, Poulton bases his suggestion of deliberate suppression on a claim that, at a certain scientific meeting, I declined to answer a question whether indeed I had known of acoustic anefacts in my work. This claim is quite untrue. In reply to his question, I immediately and categorically denied his suggestion. As verbal statements may be misheard, it is proper to repeat in print that at no time was I aware of any acoustic cues in my apparatus. Nor in fact have 1 any reason now to change that belief. As Poulton himself makes dear, he has been pressed repeatedly by myself and others to produce some concrete evidence in favour of his view that the results were artefactual. He has not however done so; and the reasons for denying his view seem overwhelming. Beyond this formal denial, going further into the questions of interpersonal relationships raised by Poulton seems neither desirable nor necessary.

P300 in Serial Tasks: an Essential Post-decision Closure Mechanism

Publisher Summary This chapter discusses P300 in serial tasks which are an essential post-decision closure mechanism. It is now agreed that event-related potentials (ERPs) are composite phenomena made up of distinct components that can be differentially manipulated experimentally and reflect different cerebral processors engaged in the cognitive task. Middle range components such as N120 are elicited when the cognitive and speed overload exceed a certain value and present a somewhat restricted scalp topography that differs characteristically with the sensory modality of the target stimuli. Primary components in cortical receiving areas (clearly documented for the somatosensory evoked potentials only) are not modified by the task conditions and represent roughly a hard-wired response occurring irrespective of wide changes in N120 or P300. On the other hand the P300 occurs maximally or only for those stimuli having been designated as targets that correspond to a task-relevant category. The small P300 sometimes described for stimuli that the subject is told to ignore may result from a failure of the subject to follow instructions or to orienting.

An auditory von Restorff effect.

In this experiment 60 undergraduates were given a serial learning task to assess the possibility of an auditory von Restorff effect. Fifteen males and 15 females learned a list of nine words presented aurally (recorded) with the same male voice (control groups). Fifteen males and 15 females (experimental groups) learned the same list as the control groups except that the sixth word was spoken by a female voice: i.e., it was isolated. The results of this study parallel the results of studies using visual stimuli. The von Restorff effect was demonstrated with auditory stimuli in that one of the experimental groups (female) learned the list with significantly fewer errors than the comparable control group. No difference was found between the male groups.

Psychological and Physiological Reactions Associated with Repetitive Tasks

The first part is a summarized report on experiments on repetitive serial reaction tasks. If the cognitive load of the repetitive task is low, a decrease of CFF and of the subjective activation level as well as an increase of the heart period variability can be observed. These symptoms of boredom are limited and changed if the repetitive tasks are associated with moderate or high cognitive loads. The second part is a summary of a survey on accounting machine operators. The results show an increasing incidence of localized fatigue symptoms with increasing ulnar deviation, or with greater angles in the elbows or the neck. It is evident that repetitive tasks are often associated with constrained body postures leading to localized fatigue symptoms.

Multiple Seriation and Learning to Read

In order to investigate the reasoning capacities involved in learning to read, a Test of Multiple Seriation (from Piaget) was developed with an alpha reliability of .76. Problems of an earlier test used by Lunzer, Dolan and Wilkinson (1976) are discussed. The results show that Word Recognition and Reading Comprehension at year 4 (age 9) correlate significantly with multiple seriation (.49 and .56 respectively). Evidence that this relationship is relatively independent of I.Q. is presented. The nature of reading as a serial ordering task, some implications for instruction and further unresolved issues, are discussed.

The interrelationships among some associative learning tasks

The purpose of this study was to determine if associative learning tasks involve two or more relatively independent factors (as suggested by an earlier study). To that end, 12 tasks were constructed; 3 were “standard” (paired associate, free recall, serial), and the others represented transition tasks between the standard tasks. The purpose was to see if factors (as determined by a factor analysis) changed in a meaningful way as the transition was made from one task to another. Some response units were single words, some were word triads; some of the word triads were meaningless, some formed sentences. Paired associate lists also differed in terms of the number of response terms to be associated with a single stimulus term. The 12 tasks were learned by 97 subjects. Two relatively stable highly correlated factors emerged, one involving free recall and serial tasks, the other involving paired associate tasks. This does not confirm the earlier work; the reason for this discrepancy is not known. Again, however, the data emphasized the importance of individual differences in associative learning in contrast to the relatively minor role of the Subject by Task interaction.

An analysis of short-term memory differences between retardates and non retardates

Retarded subjects were compared with MA-matched and CA-matched controls on serial STM tasks. Performance was measured separately for the recall of primacy and recency items, under conditions of partial (probed) and complete (nonprobed) recall. The retarded subjects were inferior to the two groups of controls on both primacy and recency items, under both recall conditions. These data are discussed in relation to the possible mechanisms underlying IQ-related individual differences in STM.