bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensory Factors in the Voluntary Application of Pressure
Authors: Provins K. A.
Published: March 2008

The experiments described attempt to assess the extent of sensory control of voluntary movements of the forearm and finger when the contractions of the muscles concerned are approximately isometric.

In the first two experiments, records were obtained of the accuracy with which subjects were able to reproduce a particular pressure with the ulnar border of the hand at different pressure values and rates of application. Results show a statistically significant increase in error of reproduction of pressure as the pressure applied decreases and the rate of application is increased.

In the third experiment, using an applied force of 25 gms. weight, a significant difference in accuracy of reproduction of finger pressure between the maximum and a slower rate of application is also shown, but not when the digital nerves are blocked by a local anaesthetic. Furthermore, there is no significant difference in accuracy of reproduction of finger pressure between the anaesthetized and unanaesthetized condition at the fastest rate of application. On the other hand, at the slow rate of application, there is an increasingly significant difference between the anæsthetized and unanaethetized condition as the applied force is reduced below 400 gms. weight, in favour of the control condition.

In the fourth experiment, subjects were trained to apply a force of 25 gms. weight using a small area of skin on the palmar surface of the index finger, then tested for their ability to reproduce the same force before and after changing the size of the area of application. Results show a marked change in applied force corresponding to the change in size of skin area used.

It is concluded that below an applied force of about 400 gms. weight, the maximum accuracy in reproduction of finger pressure is dependent upon cutaneous receptors.

The results of these experiments are discussed in relation to evidence from other experimental, clinical and animal studies and it is suggested that the major function of afferent impulses from a limb in the initiation of voluntary movements is probably facilitatory rather than sensory.
The Error Power Spectrum as a Technique for Assessing the Performance of the Human Operator in a Simple Task
Authors: Sutton G. G.
Published: March 2008

The measurement of performance of a human operator in a closed loop control system is considered; it is suggested that the power spectrum of the fluctuations of his tracking error (or error spectral density curve) gives a useful picture of performance and the equipment and technique for producing such a curve is described briefly.

As an example of the technique the power spectra obtained on several subjects performing a simple task with a pressure joystick are given and the implications of the shape of the curve are discussed.
Experimental Disorientation in the Horizontal Plane
Authors: Piercy Malcolm
Published: March 2008

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.
The Timing of Bar-Pressing Behaviour
Authors: Trotter J. R.
Published: March 2008

The time spent by a rat in a bar-pressing situation is made up of active time spent n pressing, eating time, and extra time spent in other activities. With a well trained rat, active time and extra time are small, and eating time mainly determines the rate of reward delivery. Active time is affected by a change of weight on the bar, the time between reward deliveries is affected by the amount of reward, and the extra time is affected by extinction conditions.

There is not a one-to-one correspondence between periods of activity at the knob and rewards.

The term “response” and some variables based on it are given empirical referents, which show that much research and theorizing on bar-pressing behaviour has been concerned with only a small selection of the rat's bar-pressing activities. Some reasons for this restriction are the use of the simple weighted bar, the lack of a rationale for bar-pressing research, and the practice of not watching the rat during an experiment.
After-Images from Retina and Brain
Authors: Oswald Ian
Published: March 2008

The evidence pointing to the retinal origin of after-images is considered. The reports of the occurrence of after-images from visual images of hallucinatory vividness are reviewed.

Experimental results are presented to indicate that a complementarily coloured afterimage may arise following the exposure of the temporarily blind retina to a coloured stimulus.

After-images, or after-effects, from vivid images are described in seventeen persons (mostly possessors of “number-forms”). They are found to move with the eyes and to show, in some persons, a degree of conformity with Emmert's Law which, while considerable, is less than that of after-images of real stimuli. In the case of one “eidetic” subject, the after-images from neither real nor imaged stimuli conformed with Emmert's Law. In some persons, after-images of images occur in complementary colours.

The retinal origin of after-images is affirmed, but that they can occur occasionally as a purely central phenomenon is acknowledged. The possible learned or inherent nature of after-images of central origin is discussed.
Two Theorems in Colour Vision
Authors: Brindley G. S.
Published: March 2008

Exact definitions and statements are given of some widely accepted concepts and assumptions in colour vision. Two theorems are stated, and one of them is proved (the other being self-evident). Two applications of the theorems are briefly discussed.
The E.E.G., Visual Imagery and Attention
Authors: Oswald Ian
Published: March 2008

The claim that persons may be broadly classified into imaginal types on the basis of their E.E.G. records is examined. It is found that a given individual may show a different “type” of E.E.G. from one occasion to the next. A group of persons, known to indulge spontaneously in certain recognizable varieties of vivid visual imagery, contained the same proportion of the different E.E.G. “types” as a large control sample. It was found that subjects could experience changing or static visual images without any blocking of the alpha rhythm providing that difficulty was not experienced in perceiving the images. Flat E.E.G. records were not found to be associated with regular respiration.

It is proposed that the previously reported association between alpha blocking and the appearance of visual imagery could have arisen from the fact that difficulty in thinking (a) activates mechanisms which desynchronize E.E.G. potentials, (b) provokes the emergence of visual images.
The Human Operator as a Single Channel Information System
Authors: Davis R.
Published: March 2008

A further experiment is reported on reaction times to stimuli separated by short intervals. On this occasion an auditory stimulus was followed by a visual stimulus. Results indicate that the pattern of delays at short intervals is the same as the pattern of delays when the stimuli are presented in one modality only. This suggests a model of the human operator functioning as a single channel through which information from both sense modalities has to pass before appropriate responses are organized. An attempt is also made to reconcile data with the known facts about the peripheral and central components of reaction time and the possibility that delays are the result of occupation of the channel for a central time plus a central refractory time is suggested.
The Perception of a Rotating Shape
Authors: Yensen Roy
Published: March 2008

A regularly rotated shape was matched to given shapes set in the frontal parallel plane position, under conditions which yielded practically zero constancy. It was found that increases in the rate of rotation resulted in increases in the angular settings at which the subjects matched the rotating shape to the given standard shapes. Thus Langdon's (1951) experimental results were confirmed. However, since matches to the “real” shape also increased with increases in the rate of rotation, Langdon's interpretation of his experimental results is considered to be incorrect. Further theoretical discussion is advanced in support of this conclusion: namely, that regular rotation of a shape, viewed under conditions which usually yield zero constancy, does not restore constancy.
Influence of a Depressant Drug on Acquisition in Rote Learning
Authors: Steinberg Hannah , Summerfield Arthur
Published: March 2008

Central depressant drugs have been shown to impair performance during learning and at recall. The experiment which is described was carried out to investigate whether the effect during learning is primarily on the availability of associations or on their formation. The learning decrement attributable to the drug used (30 per cent. nitrous oxide in oxygen) persisted on recovery from the drug and during subsequent learning under normal conditions. It is concluded that the effect of the drug is on acquisition rather than performance; that is, it acts so as to impede the formative process and does not merely obscure the progress of learning by blocking responses.
Method of Serial Extrapolation
Authors: Beloff J.
Published: March 2008

A psychophysical procedure is proposed for measuring a subject's power of discerning “lawfulness,” “regularity,” “invariance” in a stimulus sequence. The task consists of supplying the next term in a given series. The method is tested by applying it to a visual series consisting of lines subdivided in geometric progression. The effect upon accuracy of judgement is investigated by varying the settings of the stimulus, in particular the rate of increase or gradient of the series and the number of segments given prior to extrapolation, and of presenting the next-but-one position in the series, thereby converting the task into one of interpolation. Where possible, quantitative predictions are made concerning these variables on the basis of certain explicit assumptions.

Results show that accuracy decreases, as predicted, as the gradient of the series increases, but does not seem to be affected by adding to the number of terms presented. Interpolation shows a reduction in variable error compared with extrapolation more or less as required by theory. Finally, discrepancies in the findings are discussed with special reference to their bearing on the validity of the method.
One Trial Learning and the Suppression of Interference
Authors: James H.
Published: March 2008

An experiment was made to investigate the conditions under which a subject who has learned a series of items in one order can relearn the same items in a different order in one trial. The hypothesis tested was that one-trial learning is ensured in this situation if interference between the two tasks is reduced to zero. It is shown that complete suppression of such interference, obtained by overtraining on the task which is learned first, is not sufficient to ensure the learning of the second in one trial. Comparison of the present experiment with a similar one reported by Mandler and Heinemann (1956) suggests the hypothesis that the discovery of order in the stimulus situation is necessary, in addition to the suppression of interference, if one trial learning is to occur. The relation of the results to the problem of negative transfer is also discussed.
Some Acute Effects of D-Lysergic Acid Diethylamide on the Rat
Authors: Glow Peter H.
Published: March 2008

There is a wealth of literature available on the psychosis-like effects of very small doses of d-lysergic acid diethylamide (LSD-25) in human subjects. It is reported that the drug produces profound changes in emotional behaviour, feelings of depersonalization, visual and auditory hallucinations, catharsis-like episodes and slight changes in autonomic nervous system activity.

The present experiment investigates the possibility of relating the behavioural disturbances induced by LSD-25 to known physiological data. Variation in the latency and running times of trained albino rats is examined. It is demonstrated that latency scores are directly affected by the cerebral concentration of the drug; and that sensory thresholds appear to be raised. It is further shown that when the level of stimulation is raised the rats appear to behave normally.
Some Tests of the Decay Theory of Immediate Memory
Authors: Brown John
Published: March 2008

The hypothesis of decay of the memory trace as a cause of forgetting has been unpopular. The reasons for this unpopularity are criticized and a theory of the memory span, based on this hypothesis, is put forward. Three experiments which test the hypothesis are described. In each, two kinds of stimuli are presented to the subject, viz., “required” stimuli, which he attempts to remember, and “additional” stimuli, to which he merely makes responses. The first experiment will show that even when the number of required stimuli is well below the memory span, forgetting occurs if the presentation of additional stimuli delays recall for several seconds. The second shows that the effect of the additional stimuli depends only slightly on their similarity to the required stimuli: it also shows that their effect is negligible when they precede, instead of follow, the required stimuli. The third shows that the effect of additional stimuli interpolated before recall remains considerable even when there is an interval of several seconds between presentation of required and additional stimuli.
Blocking the Incorrect Alley in a Two-Drive Learning Situation
Authors: Deutsch J. A. , Anthony W. S.
Published: March 2008

This experiment was designed to test the effect of blocking the path to an irrelevant reward on the subject's later performance when motivated for that reward, with a view to clarifying a well-known problem-situation.

An experimental group of 17 hooded rats was run in a two-choice maze, with food in one goal-box and water in the other, being motivated alternately for one or the other. The wrong goal-box was always blocked. Their performance on the first trial of the daily series was significantly poorer than that of a control group of 18 hooded rats, for which both boxes were always open. This difference persisted when, in a second period of training, the rhythm of motivation was altered for both groups.

It is concluded that blocking an irrelevant reward can have a disturbing effect and that this may be relevant to the problem-situation. It is also shown that such a result is to be predicted from Deutsch's (1953, 1956) theory.
The Effect of Training and Handedness on the Performance of Two Simple Motor Tasks
Authors: Provins K. A.
Published: March 2008

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.
Studies in Light-Reinforced Behaviour III. the Effect of Continuous, Zero and Fixed-Ratio Reinforcement
Authors: Stewart Jane , Hurwitz H. M. B.
Published: March 2008

Two groups of hooded rats, on a 22-hr. feeding schedule, were given 21 daily ½-hr. trials of lever-pressing with mild light as the reinforcer. All animals were given seven days of continuous reinforcement and seven days of fixed-ratio reinforcement, one group on a 3:1 schedule and one on a 6:1 schedule. Five days of extinction followed for both groups and then two days of continuous reinforcement. It was found that firstly the rate of responding for the animals on the 3:1 schedule was significantly greater than for the animals on the 6:1 schedule, and secondly the resistance to extinction was greater for the 3:1 group than for the 6 : 1 group. These results were interpreted in view of the hypothesis that mild light stimulation is a “low-efficacy” reinforcer, and that for “low-efficacy” reinforcers the upper limit of the unreinforced to reinforced ratio that will elicit an increase in response rate will be lower than for “high-efficacy” reinforcers.
Some Principles Governing Changes in the Apparent Lightness of Test Surfaces Isolated from Their Normal Backgrounds
Authors: Newson L. John
Published: March 2008

When smooth matt test surfaces are suspended by fine threads in a strong illumination gradient and in isolation from any ordinary background, lightness constancy fails. It may be restored by introducing other objects into the field in the same plane as the test surfaces. Using a large number of subjects making independent judgements by a comparison scale method, the present investigation attempts to discover the principles underlying the restoration of lightness constancy by the introduction of inducing surfaces of varied size and reflectance at varied distances from the test surface.
Speech Production and the Predictability of Words in Context
Authors: Goldman-Eisler Frieda
Published: March 2008

The purpose of the experiments was to examine the function of hesitation pauses in speech. Pauses were conceived of as anticipating increase of information in subsequent speech and as involving acts of choice.

This hypothesis was tested by relating the incidence of pauses within sentences to the transition probabilities of the words constituting them. Estimates of these probabilities were obtained experimentally by an adaptation of Shannon's guessing technique and were based on reverse as well as forward guessing. The hypothesis was borne out by the facts; hesitancy in speech was shown to be closely related to uncertainty of prediction (entropy) and fluency of utterance to redundancy. These results are shown to be in line with the facts of language statistics. Their theoretical implications for the concept of information and for understanding the processes of speech organization is discussed.
Guessing, Expectancy and Autonomous Change
Authors: James H.
Published: March 2008

An attempt was made to test the hypothesis that changes in memory of the kind ascribed by Gestalt theory to autonomous processes are due, not to changes in the memory trace, but to non-random guessing. Judgements of difference between original and recognition figures are shown to be related to guesses as to what these differences are likely to be, but the relation is not such that it can be predicted from a simple guessing hypothesis.
The Restriction of Peripheral Vision during Exposure to Hot and Humid Conditions
Authors: Bursill A. E.
Published: March 2008

Eighteen, heat-acclimatized subjects were exposed to temperatures of 70/60° F. and 105/95° F. (air velocity 120 ft./min.) in three experiments requiring them to respond to a peripheral task concurrently with a continuous central pursuitmeter task. The peripheral signals were presented randomly in order and time at six positions, 20°, 50°, and 80° left and right to the point of fixation. The experimental findings suggest that when, while being subjected to high thermal conditions, operators are engaged in a central task consistently demanding their attention, there is a tendency for the field of awareness to be funnelled towards the centre. Signals presented at greater eccentric angles have a higher probability of being missed in the hotter condition. The longer the previous exposure to heat, the greater is the tendency to miss signals—but the effect does not always appear to be progressive during the actual performance. Operationally, the funnelling is defined by the proportional increase in the number of signals missed as the eccentric angle of the stimulus increases relative to the point of fixation. The phenomena does not occur when the perceptual load on the central task is reduced. Central attentional processes rather than mechanisms peripheral to the CNS are therefore implicated.
The Effect of Warning Interval on the Electric Phosphene and Auditory Thresholds
Authors: Howarth C. I. , Treisman M.
Published: March 2008

Using different warning signals and threshold stimuli, the thresholds, as determined by a method of limits, were found to rise monotonically as the interval between warning signal and threshold stimulus increased from I to 9 sec. It was found that the variability of the threshold did not increase as the threshold increased. Similar results were obtained for phosphene and auditory thresholds and with visual and auditory warnings; therefore the effect was considered to be central. Motokawa's finding of a minimum in the phosphene threshold 2 sec. after a flash of white light was not repeated. The rise in threshold was not obtained when the warning intervals were randomized and so seemed to depend on the use of fixed warning intervals. A model was developed relating threshold level to accuracy of anticipation of the end of the warning interval.
An Experimental Synthesis of the Associations and Gestalt Accounts of the Perception of Size: Part II
Authors: Joynson R. B.
Published: March 2008

A quantitative and qualitative analysis is given of the judgements described in Part I of this paper. The relation between the findings of the experiment, and the Associationist and Gestalt accounts, is discussed.
The Effect of Small Brightness Differences on the After-Effect of Seen Movement
Authors: Day R. H.
Published: March 2008

Two experiments are reported. In the first experiment the after-effect of seen movement has been shown to occur with a measurable duration when there was a small difference in brightness between adjacent parts of the stimulus pattern. In the second experiment the duration of the after-effect was observed under two conditions of brightness difference; one small and the other relatively large. The difference between the durations of the aftereffect for the two conditions of brightness difference was significant. Results from these experiments have been discussed together with data from an earlier study in which the effects of brightness differences of greater magnitude were investigated. The probable function of the duration of the after-effect with respect to brightness differences over the full range of differences has been considered.
Discrimination of Length by Sight and Touch
Authors: Kelvin R. P. , Mulik Aktu
Published: March 2008

This article reports a further investigation into the capacity to compare objects seen with objects touched. An earlier experiment had suggested that cross-modal comparisons are quite as accurate as comparisons made within the same modality: comparing a visual with a tactual stimulus showed no loss in sensitivity vis-à-vis comparisons of visual with visual and tactual with tactual stimuli (Kelvin, 1954). The results of the experiment reported below make it clear that the earlier findings, and their interpretation, were due to an oversimplified experimental situation. It now seems that cross-modal comparisons are a function of the total range of the comparison stimuli and not simply a function of the physical properties of isolated stimuli, as the first report suggested. Indeed, the present investigation makes it doubtful whether cross-modal matching is ever more than an experimental artefact.
Learning a Pressure under Conditions of Immediate and Delayed Knowledge of Results
Authors: Annett John
Published: March 2008

The results of a series of experiments on learning to reproduce a precise pressure are described and discussed in relation to a tentative hypothesis about the importance of timing of feedback signals. The evidence supports the contention that a careful analysis of the perceptual aspects of performance is necessary to account for the acquisition and retention of a precise motor response. Whilst the original hypothesis is sustained, other factors leading to the same result are clearly important. New evidence is produced which strongly suggests that cues presented simultaneously in two modalities interact. A possible distinction between sensory feedback which is used to control a response and feedback which cannot so be used, and the relation of this distinction to the learning of the response is also discussed.
Finger Localization and Finger Praxis
Authors: Benton Arthur L.
Published: March 2008

The relations between finger localization and various types of finger praxis were assessed by estimates of the inter-correlations among the performance of 100 six-year-old children. Finger localization was related significantly to those types of finger praxis which involve movements of the individual fingers with respect to each other. Right-left discrimination was related to finger localization, but not to the measures of finger praxis.

The findings are interpreted in terms of the construct of the finger schema, which can be viewed as a determinant of performance in both the localization and praxis tasks. This construct can also serve as an explanation of the observed concurrence of finger agnosia and finger apraxia as a consequence of cerebral disease.
Shorter Articles and Notes: A Case of Fluctuation of Awareness with the Pulse
Authors: Oswald Ian
Published: March 2008

The case is described of a man in whom certain percepts of central origin (after-images of hallucinations) fluctuated rhythmically with the arterial pulse. The phenomenon is explained in terms of contemporary theories of consciousness and the inhibitory effects of baroceptor impulses.

In a previous communication (Oswald, 1957) it was described how some persons may experience visual after-images not only after retinal stimulation but also after the prolonged contemplation of a voluntary vivid image (hallucination). One of those described, Subject Wi, is further discussed below. It is relevant to this case and to the interpretation suggested, to recall that Griffits and Gordon (1924) described the rhythmical increase and decrease of the size, intensity, or apparent distance of vivid images (hallucinations) with rhythmical fluctuations of vasomotor tone, of pulse rate and, by inference, of blood pressure.
Tactual Choice Reactions: I
Authors: Leonard J. Alfred
Published: March 2008

The purpose of the experiment was to observe the effect of varying the number of alternatives on choice reaction time in a task having an initial high degree of compatibility. The stimuli were presented as vibrations of relay armatures to 1, 2, 4, or 8 fingers separately, and the response was to depress the armature by the finger so stimulated. The results showed a difference between simple reaction time and two-choice times, but no systematic differences among 2, 4, or 8 choice times. The implications for further research are discussed.
Changes in Behaviour Associated with a Nervous System Poison (DDT.)
Authors: Khairy Melek
Published: March 2008

The main purpose of the investigation was to show that behaviour measures can be used to investigate the effects of those toxic drugs which produce “biochemical lesions” in the nervous system although the nature of the lesions still remains undetermined. The advantages of this approach are twofold. First, a psychological study may help to uncover the initial effects of the drug, and thus provide evidence which may lead to the ultimate understanding of the action of the drug. Second, and of value from the practical point of view, such a method may be used to detect toxicity.

In this study D.D.T. was used. Two experiments were performed on one control and four experimental groups of albino rats. Problem solving behaviour, speed and pattern of locomotion, and reaction to stress involving visual stimuli were observed.

Problem solving behaviour was found to be unaffected by the drug; no changes were found in speed of locomotion, but pattern of locomotion revealed that “ataxia” was one of the initial effects of D.D.T. poisioning. The experimental animals were found to be generally less reactive to “stress”; “hyper-irritability” reported in previous studies being explicable in terms of exaggerated motor responses.

The results obtained on “ataxia” showed that the procedure adopted here could be used to detect chronic D.D.T. toxicity in rats.
Shorter Articles and Notes: Intelligence Level as a Variable in the Perception of Shape
Authors: Leibowitz H. , Waskow I. , Loeffler N. , Glaser F.
Published: March 2008

The relation between shape constancy and intelligence was investigated by determining the functions relating matched shape to the angle of inclination of a circular test-object for groups at four levels of intelligence. Subjects were obtained from groups of institutionalized mental defectives, slow learners from the public schools, unselected undergraduates, and undergraduates who had been awarded scholarships. With increasing intelligence level the matches tend to approach the prediction based on the law of the retinal image thus demonstrating an inverse correlation between intelligence and the extent to which constancy is demonstrated. Since it is known the instructions given to the subject are a variable in shape constancy, it is suggested that the present data are the result of different attitudes adopted by the subjects at the various intelligence levels. The more intelligent subjects are assumed to adopt an analytic attitude in the experimental situation, while the less intelligent tend to maintain their everyday, non-analytic modes of perceiving.
Apparatus: An Air Dilution Olfactometer Suitable for Group Threshold Measurements
Authors: Cheesman G. H. , Kirkby H. M.
Published: March 2008

An apparatus is described by means of which a series of smelling points may be kept independently supplied with constant controlled concentrations of odorous material.
Changes in Threshold Level Produced by a Signal Preceding or following the Threshold Stimulus
Authors: Treisman M. , Howarth C. I.
Published: March 2008

In a previous experiment (Howarth and Treisman, 1958) it was shown that when a warning preceded a stimulus by a fixed interval, the threshold level for the stimulus was higher the longer the fixed interval. A model of this effect was proposed, assuming that the threshold criterion adopted by the subject at any moment was modified by his estimate of the probability of a stimulus at that moment.

Three predictions are derived and tested. It is found that: the standard deviation of the response is constant despite the shifts in threshold induced; the threshold continues to fall as the interval from warning to stimulus is decreased to zero, with the lowest threshold when the warning signal and the stimulus are simultaneous; and that a warning signal following the stimulus by an interval of less than 0 5 to 1 sec. also lowers the threshold.
A Test of the Neo-Behaviouristic Theory of Extinction
Authors: Deutsch J. A. , Clarkson J. K.
Published: March 2008

A test between Moltz's and Deutsch's theory of extinction was devised. Animals were trained to go to the same goal-box via two different paths. Then they were divided into two groups. The first found the goal-box empty, the second found the entrance into the goal-box blocked. The choices of the animals on the next trial were observed. The results are those predicted by Deutsch.
Reasoning in the Hooded Rat
Authors: Deutsch J. A. , Clarkson J. K.
Published: March 2008

A problem situation was devised to test Deutsch's (1956) theory of reasoning. In this situation various problems can be set the rat and these problems admit of various equally rational solutions. Predictions from the theory were made, not only that the animals would solve the problems, but also which particular solution they would adopt. These predictions are confirmed. The rats were trained to run to two goal-boxes, one near, the other more distant. The near one had two paths of equal length leading to it, the more distant goal only one. After training, the animals chose the near goal-box on the first trial of the day. On the test trials the near goal-box was left empty, or the chosen path blocked, or a mesh placed across the goal-box, with the food accessible via the other short path.
The Hull-Leeper Drive Discrimination Situation—A Control Experiment
Authors: Deutsch J. A.
Published: March 2008

An experiment was conducted testing the author's explanation of the discrepancy between results obtained by Hull and Leeper in a similar situation. Animals were run either hungry or thirsty to obtain the appropriate reward by making one response when hungry and another when thirsty. For all groups the reward was in the same goal-box. The first group (Leeper) had the goal-box divided with each side being accessible only if the animal had made the correct response initially. The second group (Hull) had the same goal-box for both rewards, but if the wrong path was taken the animal was prevented from reaching the goal by a block. The third group had the same goal-box for both rewards again, but the animal could reach the goal-box even if the wrong path was taken and discovered the unwanted reward in the goal-box. The results confirm the predictions made from the author's theory.
Evidence of a Single-Channel Decision Mechanism Limiting Performance in a Serial Reaction Task
Authors: Welford A. T.
Published: March 2008

An experiment is described in which the subject sat facing a display of two neon bulbs. When the left-hand bulb lit he pressed a key under his left hand, and when the right hand bulb lit he pressed a key under his right hand. The left-hand bulb gave brief flashes at random intervals averaging about 4 sec. The right-hand bulb gave a brief flash at regular intervals of about 4 sec.

The experiment repeats (the author believes for the first time) certain essential conditions of Vince's (1948, 1950) experiments and, following detailed scrutiny of every pair of responses, is taken as evidence for the following statements:— (a) The response to a signal arriving during the reaction time to a former signal will be delayed by an amount approximately equal to the time elapsing between the arrival of the signal and the end of the reaction time to the former signal. (b) An exception to this may occur when two signals arrive close together. In this case the two signals may be responded to as a single group. (c) Delays can be occasioned by the monitoring of responses as well as by reactions to signals. (d) “Grouping” of signal and monitoring may occur when a signal arrives close to the beginning of the movement made in response to a previous signal.

A survey is made of current theories in this field and suggestions given for further research.
The Role of “Attention” in the Psychological Refractory Period
Authors: Davis R.
Published: March 2008

A set of experiments is described in which two consecutive signals, separated by a variable time interval, were presented to the subjects. Manual reaction times to these signals were recorded and the delays in the reactions to the second of the two signals were compared in situations where the subject was required to respond to both signals and where he was not required to respond to the first signal.

The magnitude of the delays found at any particular interval were the same in both situations, and there was not much difference between cases where the two signals were in the same sense modality (visual) or in different modalities (visual, followed by auditory). These results confirm the suggestion of the writer in a previous paper that there may be a common analysing and classifying system for auditory and visual information and also illustrate a new point. It is paying attention to a signal rather than performing any overt response to it which gives rise to delays in subsequent responses.
Retroactive Raising of a Sensory Threshold by a Contralateral Stimulus
Authors: Halliday A. M. , Mingay Rosemary
Published: March 2008

In an experiment designed to extend Howarth and Treisman's recent observations on the lowering of the visual and auditory threshold produced by a warning stimulus, it has been found that the threshold to electrical stimulation of one forearm is raised by a similar stimulus on the other forearm. As in the earlier experiments the “warning” was effective if it came 100 millisec. before or after the threshold stimulus. The effect increased with increasing warning strength over the range of five near-threshold strengths used.

These results appear to be inconsistent with the explanation previously proposed to account for the retroactive lowering of threshold. This suggested that the warning was acting simply as a marker, reducing the subject's uncertainty as to when the stimulus was coming. The fact that the rise in threshold was also induced retroactively shows that some interaction must be occurring in the central processes concerned in perception, and that it cannot be explained in terms of attenuation of the afferent volley.
Lowering of an Auditory Threshold by a near Threshold Warning Signal
Authors: Howarth C. I. , Treisman M.
Published: March 2008

Following previous experiments on the effect of suprathreshold “warning” signals in lowering the threshold for stimuli in another modality, we have used visual “warning” signals which are themselves within the threshold range. These near threshold “warnings” appear to act in exactly the same way as suprathreshold “warnings” provided they are seen. Very weak “warnings” have a reduced effect, probably because they are not always seen. The experiment is of interest in that it supports the theory that the effect is due to the “warning” signal reducing the subject's uncertainty about when the threshold stimulus will occur, and secondly because it indicates that under these conditions at least, the subject can attend effectively to two simultaneous near-threshold stimuli.
An Investigation of a Satiation Process in the Reversible Perspective of Revolving Skeletal Shapes
Authors: Howard I. P.
Published: March 2008

A technique for studying a satiation process is described, which is claimed to have many advantages over the older methods. A skeletal wire cube is rotated at 1 rev. per sec., and the time taken for the first apparent reversal of direction to occur is measured and called the “satiation period.” It is a much longer period than the mean period of subsequent reversals. This is due to the fact that the situation is one of biased ambiguity; biased by the cues to depth and thus to the true perspective.

Using this measure we have shown:—

(1) That the effect is predominantly central.

(2) That after satiation has occurred, reversing the cube's direction of rotation induces a longer than normal satiation period.

(3) There is no transfer of satiation to other types of static or mobile figure nor to other spatial locations.

(4) Satiation time is largely independent of brightness and colour.

(5) Köhler's theory of satiation is supported but it is given a neuronal basis rather than a basis in a non-neuronal, electrolytic type of cortical conduction.
The Effect of two “Tranquillizers” on Auditory Discrimination and Delayed Response Performance of Monkeys
Authors: Gross Charles G. , Weiskrantz Lawrence
Published: March 2008

Five rhesus monkeys were tested on performance of an auditory discrimination and a delayed response test with a sliding scale of increasing difficulty after treatment with ( a) 0·2 to 0·5 mgm./kgm. reserpine, ( b) 150 mgm./kgm. meprobamate, ( c) an equivalent saline injection, and ( d) no treatment. Both drug treatments resulted in a severe deficit on the auditory discrimination and no change or improvement in delayed response performance. The auditory deficit was not due simply to an increased latency of response.

It is suggested that these results support the hypothesis that reserpine and meprobamate reduce the utilization of sensory information.
Visual Orientation Preferences in the Rat
Authors: Dodwell P. C.
Published: March 2008

An experiment was performed which demonstrated a preference in hooded rats for vertical rather than horizontal striations. It was demonstrated that experience in discriminating between horizontal and vertical striations facilitates subsequent discrimination between squares and circles, regardless of which type of striation was positive in initial training. This finding has implications for theories of shape recognition, which are discussed.
Shorter Articles and Notes: Like and Cross Modality Recognition in Subnormal Children
Authors: O'connor N. , Hermelin B.
Published: March 2008

The ability of mentally subnormal children to recognize previously presented visual or verbal stimuli was compared. In “like-modality” procedures they had to recognize words or pictures in the modality in which they had originally been presented. In “cross-modality” procedures the stimulus they had to recognize was in the opposite modality from that which had been used for the first presentation.

In every recognition test the items had to be recognized from among an equal number of novel stimuli. Cross-modality procedures resulted in higher recognition scores. The hypothesis is advanced that this could be accounted for by the necessary translation from one type of sensory image to another in the cross-modality trials, which might minimize over-generalization.
A Note on the Influence of Different Orders of Approximation to the English Language upon Eye-Voice Span
Authors: Lawson Everdina A.
Published: March 2008

An experiment is described in which the effect of changing information content of stimuli upon the eye-voice span in reading is investigated. Subjects were required to read aloud statistical approximations to English. It was found that the eye-voice span is inversely related to the information content of the material read. This would support the suggestion of a constant rate of information transmission in reading, since the different orders of statistical approximations differ in the amount of redundancy present in the material.
Imprinting and Perceptual Learning
Authors: Sluckin W. , Salzen E. A.
Published: March 2008

Filial responses are first considered by reference to the initial stimulus situations. Findings on variability in responsiveness of chicks are reported and discussed. Facilitated responsiveness subsequent to visual stimulation is reported. The concept of critical period is examined in the light of other workers’ and our own findings; it is concluded that imprinting ends as a result of its own action rather than through the effects of fear. Following responses are further considered by reference to the influences of early experiences and the act of following upon the occurrence and strength of subsequent responses. The degree of attachment to a moving object tends to be proportional to the amount of experience. Individual chicks were allowed to spend several hours following a box in a runway and their ability to discriminate between familiar and unfamiliar moving objects and static environments was studied. Strong evidence for imprintability to environment has been found. Imprinting phenomena are discussed in terms of perceptual learning.
Imitative Responses and the Rate of Gain of Information
Authors: Davis R. , Moray N. , Treisman Anne
Published: March 2008

A series of experiments is described on audio-verbal reaction times. In the first experiment the signals were letters or digits recorded on magnetic tape and presented through earphones. In the second experiment the signals were nonsense syllables drawn from vocabularies of different size. The subjects responded by repeating what they heard as soon as it was presented and reaction times were recorded. It is shown that the size of the group from which the signal is drawn has little effect on the reaction time to that signal. A distinction is drawn between situations in which the rate of gain of information may be expected to apply and situations in which it may not apply. It is suggested that many highly practiced skills fall into the latter category.
Visual Discrimination of Horizontal and Vertical Rectangles by Rats on a New Discrimination Training Apparatus
Authors: Sutherland N. S.
Published: March 2008

A new visual shape discrimination apparatus for use with rats is described. Rats were trained on a simultaneous discrimination using stereometric shapes, and the reward was milk which was delivered through the middle of the shapes. Animals were trained to discriminate vertical and horizontal rectangles on the apparatus, and it was found that they took as many trials to learn as on a Lashley jumping stand. Because of the speed at which individual trials may be conducted, less actual time is spent on training in this apparatus than in a Lashley jumping stand. Some transfer tests were conducted and indicated that: (1) although the bottom halves of the shapes were more important for rats than the top halves, animals had learned something about the shapes as a whole; (2) animals transferred to discontinuous shapes; (3) they transferred better to larger shapes than to smaller; (4) they had learned both to approach the positive shape, and to avoid the negative shape.
Laterality and Directional Preferences in a Simple Perceptual-Motor Task
Authors: Reed G. F. , Smith A. C.
Published: March 2008

The superiority of tensor or outward movements of hand and arm over flexor or inward movements has been described, but no evidence has been found relating to directional preferences in simple perceptual-motor tasks.

One hundred children, aged 9 to 13, 50 being right-handed writers and 50 left-handed writers, were tested on a stroke-making task, using both preferred and non-preferred hands. 75 per cent, of them exhibited a preference for outward movements of both hands, a finding which applied equally to both handedness groups. Thus an explanation based on writing habits is discounted.