The effect of training and handedness on the performance of two simple motor tasks

In the first experimental series nine right-handed and nine left-handed subjects were tested on each side on two tasks. The first task measured the accuracy of reproduction of pressure in attempted extension of the elbow joint, and the second the speed of oscillation of attempted flexion and extension of the elbow joint. The results showed no significant difference in performance on the two sides in the accuracy task but a significant difference in performance on the speed task.

In the second experimental series the effect of 15-minutes daily training on each of two tasks over a four-week period was investigated on six subjects. The two tasks were the same as those used in the first experimental series, and attempted movement at the metacarpo-phalangeal joint as well as the elbow joint was studied. The mean results of all subjects showed a significant reduction in the mean error of the “accuracy” task over the training period for both the finger and arm. However, further analysis suggests that this may have been due to a clarifying of the subjects' concept of the target value rather than an improvement in his ability to grade the appropriate muscle contractions. A significant increase in the mean speed of oscillation over the training period was also recorded for both finger and arm. This improvement was accompanied in most instances by a corresponding decrease in variation of cycle length of the individual oscillations, which is interpreted as an improvement in the subjects' “timing” of the appropriate muscle contractions.     

A study of position habits induced by reward and “frustration”

Predictions from Maier's theory of “frustration”-instigated behaviour have been tested in an experimental situation differing significantly from that in which the theory was propounded yet containing the central element of “frustration”—the insoluble problem.

A water discrimination unit was employed in which the performance of rats would be observed during attacks on insoluble problems, position problems or symbol problems.

Two groups, each containing ten Wistar albino rats, served as subjects. The research design consisted of the following phases: preliminary training, development of position responses, exposure to a symbol-reward problem with 50 per cent, punishment and exposure to a symbol-reward problem with 100 per cent, punishment. The design differed for the two groups only at the phase in which the position responses were established. During this phase one group was exposed to a position-reward problem and the other to an insoluble problem.

Position responses were established as frequently under position-“frustration” (position stereotypes) as under position-reward (position habits) conditions. Position stereotypes were more rigid—more resistant to extinction—than position habits under conditions of 50 per cent, punishment. Position stereotypes were as readily extinguished under 100 per cent, punishment as were position habits under 30 per cent, punishment.

The first two observations conform to predictions made from Maier's theory. The third does not. That is to say, not all situations containing the basic elements of “frustration” give rise to stereotyped behaviour patterns which are as rigid or “fixated” as Maier's theory would predict. It is a reasonable hypothesis that the characteristics of stereotyped responses established in certain “frustration” situations may be described adequately in terms of conventional learning principles without the necessity of resorting to a distinction between “goal-motivated” and “frustration-instigated” behaviour.     

Frustration and stereotyped behaviour in human subjects

The investigation was designed to show the effects upon behaviour of three different durations of frustration, and two degrees of motivation during the frustrating period. Frustration was induced in 144 subjects by setting them the task of “learning” an insoluble temporal maze; they had to record their responses by pressing on one or other of two morse-type keys. Its effect was measured in terms of:

(1) The time taken to learn a soluble maze introduced, without the subjects' knowing it, by changing the system of “rewarding” responses from one based on chance to one based on the constant repetition of a pattern requiring the responses: Left—Right—Right, for its solution.

(2) The tendency for the subjects to show stereotypy of behaviour by responding on the same key for a number of trials in succession without reaching a solution.

(3) The pressure exerted on the response keys, which was taken to be a measure of vacillation.

Predictions that the time taken to learn the soluble task, and the stereotypy, would increase in direct relation to the duration of the frustrating period and the degree of motivation were tested.

It was found that, while there was an immediate increase in both the time taken to learn the soluble task and the stereotypy after a short period of frustration, a point was reached under conditions of prolonged frustration after which no further increase occurred and some adjustment to the situation was shown.

Some confirmation of the effect of increase in motivation in the direction predicted was obtained in all cases, but the differences were not statistically significant. The rankings of the subjects according to the time taken to learn the soluble task and the degree of stereotypy were found to be closely correlated. A definite tendency towards increased vacillation of response was seen in many of the records during the period when frustration might have been expected to have been at its peak.

These findings are discussed in relation to Maier's theory of frustration and to Selye's concept of a “general adaptation syndrome.” The latter theory is more suitable for the interpretation of the results of the present investigation.     

Comparative analysis of proprioception in left and right arms

Using the “kinaesthetic memory for the target” technique, differences in the accuracy of pointing to a target with the right and left arms are analysed. The effect of rotation of the head to left and right upon this process is also studied.

With the head normally orientated, it was found that pointing with the right arm is significantly better than with the left. Accuracy of pointing is greater with the target directly in front of the body than when it lies to either left or right side.

When the head is rotated, the direction of the pointing error is inversely related to the direction of rotation.

The study suggests that the precision of control over arm (in the absence of vision) is related to the varying ability of individual subjects to correlate limb movements with the prevailing orientation of the body, especially of the head and neck. This is additional to the influences of genetically-determined handedness and of the sensory input from the moving limb.     

The imaginaiy questionnaire

The experiment was designed to throw some light on the statistical problems in the analysis of questionnaire data. Previous work (unpublished) suggested that a simple choice response was partially determined by previous responses; and also that the nature of the determination was changed with changing length of series. A “null” experiment was devised in the form of a questionnaire without any questions, and the distribution of responses was studied with respect to the problems formulated.

The observations are discussed in three sections.

In the statistical discussion an alternative meaning to overall association or dissociation is advanced. This: relates association or dissociation to human behaviour in the serial response situation, rather than to qualities of the questionnaire. It is further suggested that association between specific, questions should be tested against the association in the whole questionnaire, and an appropriate treatment is indicated.

The observations depart from statistical randomness in certain ways. Answers made up almost entirely of one form of response are given less often than would be expected. Long sequences of the same type of response are relatively infrequent, and sequences of alternation of response are also rare. As the material is “null” it implies that the human concept of randomness differs from the statistical concept.

An attempt is made to define the human concept of randomness. It appears that a series of responses which has a pattern, or for which the subject can postulate a simple “cause” will not be accepted as random by the human subject. This raises problems of a perceptual and cognitive nature. It also has a bearing on the design of questionnaires. or experiments involving serial responses.     

Effects of nitrous oxide on reactions to “stress”

It has been demonstrated that exposure to the stress of a situation involving conflict or frustration may interfere significantly with subsequent learning. Behaviour under stress is characterized by experiences of “anxiety” and by widespread physiological changes. Inhalation of nitrous oxide has the general effect of reducing the extent of these symptoms.

The present investigation using insoluble and soluble problems has demonstrated that both nitrous oxide and exposure to stress impair learning; but that, when subjects are exposed to stress while under the influence of the drug, the effects of the stress on subsequent learning are abolished. It is suggested that these empirical results may be accounted for either in terms of “anxiety-reduction” or in terms of transfer effects.     

Selective effects of an anaesthetic drug on cognitive behaviour

The prediction has been tested that under the influence of an anaesthetic drug, nitrous oxide, cognitive performances undergo differential impairment, the extent of which is positively correlated with the “complexity” of the task, Ten kinds of performance were investigated, ranging from speed of finger tapping to reasoning by analogy. The relative complexity of each task was determined, in accordance with conventional criteria, from its respective qualitative category or “level”—relational, associative, and motor—and within each category from qualitative analysis of the component processes involved in its execution. A simple group difference design was used, involving two groups of 50 subjects each, matched for age and sex.

Significant deterioration as a consequence of drug administration occurred in the performance of all tasks. On the whole, the more complex a task the more did it tend to be impaired. Motor performances were, however, impaired to a greater extent than had been predicted. The possible significance of these findings is discussed.     

Phenomenal causation at a distance

The aim of this research was to study the finding by Michotte, that a moving object A can apparently produce movement in a projectile B without making contact with it.

The experiments confirm the existence of a causal impression of “pushing at a distance,” but they demonstrate that the greater the distance the smaller the chance that this impression will occur.

When it does, in fact, occur, it has the same characteristics, and is associated with the same experimental conditions, as the impression of “pushing with contact.”

Temporal continuity must obtain between the stopping of the moving object and the starting of the projectile; this refutes any theory positing that there is a “passage” of movement from one object to the other. The effects of differences in speed of movement, whether absolute or relative, are similar in both instances.

In general, however, it appears that distance slightly accentuates the segregation of the movements and that the temporal and kinematic conditions of integration require to be more favourable in the case of distance, if an impression of pushing is to be given which is as satisfying as that found in the case of direct contact.

The size of the Radius of Action, that is, the extent of the passive phase of the projectile, is of the same order in the two cases.

The results bring out the fundamentally temporal-kinematic nature of the perceptual pattern of pushing. They appear difficult to reconcile with an interpretation based on past experience, but tally with the theory of “Ampliation of Movement” put forward by Michotte. According to this theory the essential point lies in the phenomenal transitory belonging to A (the moving object) of the movement performed by B (the projectile).     

Subjective assessments of firmness: The use of a rating scale

An experiment was carried out to investigate the extent to which an absolute standard for firmness could be held independently of variations occurring within the samples being judged.

Although the method gave good results as a whole, it was found that, when correlating the ratings to the objective measurements, the absolute standards were not held independently of the average firmness of the groups being judged. In practice, if a certain sample was judged, within a “soft” series of samples, it would be rated as being firmer than when it was judged among “firm” samples. Certain differences in the effects of these changes were related to the nature of the subjects' previous experience.

When the results were considered on a relative comparison basis, it was found that a much lower threshold was achieved than had previously been obtained with judgments for springs using paired comparison methods. There were certain trends in the levels of discrimination with time. These trends are discussed.

The strength of grip of the subjects bore some relation to their initial rating values, but apparently was not related to their level of discrimination. Subjects who were able to exert a more constant pressure throughout the test did not seem to be any better at discriminating than were others.

Ratings made for a single sample two months after the main experiment were very similar to those previously given for the same sample.     

On the rate of gain of information

The analytical methods of information theory are applied to the data obtained in certain choice-reaction-time experiments. Two types of experiment were performed: (a) a conventional choice-reaction experiment, with various numbers of alternatives up to ten, and with a negligible proportion of errors, and (b) a ten-choice experiment in which the subjects deliberately reduced their reaction time by allowing themselves various proportions of errors.

The principal finding is that the rate of gain of information is, on the average, constant with respect to time, within the duration of one perceptual-motor act, and has a value of the order of five “bits” per second.

The distribution of reaction times among the ten stimuli in the second experiment is shown to be related to the objective uncertainty as to which response will be given to each stimulus. The distribution of reaction times among the responses is also related to the same uncertainty. This is further evidence that information is intimately concerned with reaction time.

Some possible conceptual models of the process are considered, but tests against the data are inconclusive.     

Variations in reflex blink-rate during visual-motor tasks

The influence of the performance of various tasks on the reflex blink rate has been investigated repeatedly, but the results obtained have been somewhat contradictory. More recently, it has been suggested that the reflex blink rate may be a considerable factor in the accuracy with which visual-motor tasks are performed. The aim of the present experiment was to attempt to obtain further evidence on both these questions.

The experiment was carried out in two parts. The main part was done in the laboratory, while a validating experiment was carried out on the road. In the laboratory, subjects were required t o steer a pencil along a moving track which varied in difficulty. The difficulty of the response was varied by using a direct control on some trials and a velocity control on others. Blink rate, errors, and control measurements were recorded throughout. In the road experiment, cine films were taken of the driver's eyes while driving in heavy traffic and in open country.

The results of both experiments show:

(a) That there are marked individual differences in blink rate, the relative order of which is maintained in spite of variations in the actual blink rate.

(b) That there is no relationship between the accuracy with which a particular individual carries out a task of this sort and his blink rate. The rapid “blinker” is no more and no less likely to be accurate than the infrequeiit I “blinker.”

(c) That the actual blink rate for all individuals varies inversely with the difficulty of the task and the amount of control movement necessary. The blink rate decreases as the necessity for detailed visual control of movement increases. Blink rates when driving a car in heavy traffic, or when steering along an oscillating track, are considerably lower than when driving in open country or when following a straight track.

(d) That the adjustment of the blink rate to the difficulty of the task is achieved not only by an alteration in overall blink rate, but also by a change in the distribution of blinking. The blink rate is approximately constant under constant conditions, but when the task is varying in difficulty, blinking occurs just before and just after periods of maximum difficulty, but is completely inhibited during the periods of maximum difficulty itself.     

A further study of the pendulum phenomenon

A first series of experiments had demonstrated certain conditions eliciting or inhibiting a “pendulum” phenomenon in the visual perception of apparent movement. The present study consists of five further variations designed to show more clearly conditions of occurrence and non-occurrence of this type of movement. The main findings are:

(i) Altering the axis of display to vertical significantly reduces the frequency of pendular-movement perception;

(2) Altering the position of metronome from behind to the side of the visual display, gives results almost identical with those where the metronome was inaudible, but, when the metronome is illuminated in this position, all forms of movement perception are reduced, and no pendular movement is reported.

The results for all the ten conditions, including the five of the first series are summarized, and the following possible factors are discussed: past experience, physiological nystagmus, and intervening adaptation. All three may be required to account for the perceptual phenomena under investigation and the dichotomizing of explanations into “experiential,” or “physiological,” appears to be arbitrary and inconsistent with the complexity of the observed facts.     

Discrimination of “W” and “V” shapes by goldfish

Goldfish were trained to discriminate between “W” and “V” shapes; different groups were trained with the shapes in different orientations. Transfer tests were given after training and the following conclusions were drawn. Animals learned to discriminate between the training shapes by detecting the difference in the number of points present in each; they learned the difference in the relative number of points rather than the absolute number present in each shape; the subjects transferred well to pairs of shapes bearing points facing in different directions from those on the training shapes; knobs were treated as practically equivalent to points; animals relied more heavily on differences at the tops of the shapes than on differences in the bottom halves.     

Information relevance, working memory, and the consideration of alternatives

People routinely focus on one hypothesis and avoid consideration of alternative hypotheses on problems requiring decisions between possible states of the world--for example, on the “pseudodiagnosticity” task (Doherty, Mynatt, Tweney, & Schiavo, 1979). In order to account for behaviour on such “inference” problems, it is proposed that people can hold in working memory, and operate upon, but one alternative at a time, and that they have a bias to test the hypothesis they think true. In addition to being an ex post facto explanation of data selection in inference tasks, this conceptualization predicts that there are situations in which people will consider alternatives. These are:

1. “action” problems, where the alternatives are possible courses of action;

2. “inference” problems, in which evidence favours an alternative hypothesis.

Experiment 1 tested the first prediction. Subjects were given action or inference problems, each with two alternatives and two items of data relevant to each alternative. They received probabilistic information about the relation between one datum and one alternative and picked one value from among the other three possible pairs of such relations. Two findings emerged; (1) a strong tendency to select information about only one alternative with inferences; and (2) a strong tendency, compared to inferences, to select information about both alternatives with actions.

Experiment 2 tested the second prediction. It was predicted that data suggesting that one alternative was incorrect would lead many subjects to consider, and select information about, the other alternative. For actions, it was predicted that this manipulation would have no effect. Again the data were as predicted.     

Some effects of thiamine deficiency and reduced caloric intake on “behaviour under stress” and on learning

The main purpose of the investigation was to determine the effects of thiamine deficiency in rats on behaviour under stress and on learning. Since thiamine deficiency reduces food intake, it was necessary to have two control groups. The first received adequate thiamine, but a food intake reduced to that of the vitamin-deficient animals; the second received adequate thiamine and an unrestricted food intake. It was thus possible to study the effects both of thiamine deficiency and of reduced caloric intake on the behaviour variables measured.

The experimental group was maintained on a thiamine-deficient diet throughout the entire experimental period. Because of the effects of thiamine deficiency on caloric intake, food-hunger was never used as a form of motivation. Behaviour in four different situations was studied: in Hall's open-field test, in two discrimination situations both involving exposure to insoluble and soluble problems, and in a water maze.

Contrary to the findings of several previous studies, there were no significant effects of thiamine deficiency on behaviour prior to the onset of polyneuritis with its debilitating effects on motor co-ordination. There was also no evidence of impairment in any of the behaviour studied which could be attributed to restrictions in caloric intake. This was the case even though the restrictions continued for a period of somewhat more than twelve months. Although these restrictions did not lead to impairment they were associated with certain changes in performance. Animals whose feeding was restricted were more active and, during the soluble phase of one discrimination situation, showed more vicarious trial and error and learned more readily than animals fed ad libitum on the same diet. It is suggested that these differences may be interpreted in terms of the effects of what previous investigators have referred to as “irrelevant drives”.     

Comparison of the effect of hard and easy mental arithmetic upon blocking of the occipital alpha rhythm

The intensity of blocking of the alpha rhythm of the EEG induced by the solution of five Hard mental multiplications has been compared with the intensity of blocking induced by five Easy mental multiplications in 36 normal subjects. From predictions derived from the application of two hypotheses concerning the intensity of blocking, it would be anticipated, firstly, that blocking would be more intense in the Hard tasks, if their solution required increased mental concentration and, secondly, that insofar as “higher thought” processes are more extensively required in the solution of Hard tasks, then blocking would be less intense in Hard tasks than in Easy tasks. However, the findings of the experiment have been that blocking is of the same intensity in tasks of both kinds. Possible reasons for this are discussed.

Hard tasks differed from Easy tasks, with regard to the relation of EEG changes and performance. It is thought that different mechanisms may underly the solution of the two types of task.     

Hand preferences and hand ability in congenitally blind children

Congenitally blind and sighted blindfolded children between the ages of 6 and 14 years were tested for hand preference with performance tasks. There were no differences between the groups in direction or degree of hand preference. The degree of handedness increased with age and was essentially linear though the blind seemed to be somewhat less lateralized at the younger ages.

When the same groups were required to match three-dimensional bricks for height, depth, breadth, and volume, no hand advantages were found for either group. Both groups of children improved in their accuracy of spatial discriminations with age.

Further, the degree of lateralization on the handedness task did not relate to ability on the tactile task or to differences between the right and left hands on the tactile task. Thus, there is no effect of blindness on tactile matching ability nor is there an effect of the hand used in the task.     

Selective interference during the retrieval of visual images

Twenty-six subjects memorized lists of (low I and high I) noun pairs under imagery or verbal mediation instructions. At recall the subjects were presented a digit (“1” or “2”) either auditorily or visually as an interfering stimulus.

Visual interference was found to selectively affect the retrieval of high I response terms. Also, the retrieval of nouns studied by imagery mediation was found to be selectively disrupted by visual interference.

These results suggest that the qualities of a visual image are retained all the way from image acquisition to retrieval, and that the visual components of images generated at the acquisition stage are probably not lost by subsequent coding processes.     

A test of sensory pre-conditioning in pigeons

Sixteen pigeons were used in an experiment designed to show the sensory preconditioning effect as originally reported by Brogden. An experimental group received 200 simultaneous presentations of a buzzer paired with a light stimulus. They were then trained to respond to one of these stimuli alone and tested for response to the other. A control group received the same treatment except in the initial stage when 200 presentations of the test stimulus only were given. The results provided no evidence that the pairing of stimuli affected behaviour during the critical test.

Both groups responded to the test stimulus to a similar degree in this experiment, whereas in Brogden's original study with dogs experimental animals responded significantly more frequently than did their controls. The discrepancy in results can be attributed to the use of different control procedures in the two experiments. Brogden's controls were not exposed to presentations of the test stimulus before training. Differences in familiarity with this stimulus may have produced the differences between the behaviour of his control and experimental animals. This interpretation is supported by the result of a preliminary experiment with pigeons in which Brogden's control procedure was used and his original results confirmed.

With human subjects there is some evidence that pairing procedures may result in enhanced generalization, alterations in sensory thresholds or hallucinations. However, these effects are little understood and difficult to predict. Although no functional relationships like those found in ordinary conditioning have yet been shown to apply, the terms “sensory conditioning” and “sensory pre-conditioning” have been widely used and the data have been quoted in support of theories of learning that require the setting up of direct sensory-sensory relationships.

Until there is unequivocal evidence of pairing effects with animals or fuller knowledge of the occurrence of such effects with human subjects, it is considered unadvisable to link them even by name with basic learning mechanisms such as conditioning.     

Experimental disorientation in the horizontal plane

Twenty-eight subjects were examined on a visual matching task for their ability to maintain an orientation with respect to a particular direction in the horizontal plane following a voluntary rotary body movement through 180 degrees. Each subject was examined with respect to eight different directions.

Numerous gross errors occurred when visual information was reduced to the display of an arrow indicating a direction and a second arrow manipulated by the subject. The magnitude and distribution of the errors suggest that, under the conditions of this experiment, visual information as to direction in the horizontal plane is analysed according to the two horizontal dimensions defined by the sagittal and coronal planes of the head. In correcting for the rotary body movement, failure may occur with respect to either or both of these two dimensions. The frequency of a failure to make any correction at all (i.e. 180-degree errors) is consistent with independent failure in each of the two horizontal dimensions.

Failure is markedly more frequent in the fore-aft dimension than in the left-right dimension. It is suggested that this may be explained in terms of the ambiguous spatial significance of vertical disposition on the retina and the possibility of contamination between the two systems of conceptual analysis which identify the vertical and the fore-aft dimensions of visual space.

It is demonstrated that when minimal “landmarks” are provided they tend to be utilized as reference points in attempts to maintain orientation, even when the subject is aware that the “landmarks” are misleading. Such a use of “landmarks” does not suppress the previously mentioned mechanism of dimensional orientation.

The relevance of these results to normal human orientation is discussed.