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The paper discusses the effect of the assumed decision interval on the measurement of d'. Previous experiments have revealed a decrement in the detectability (d') of signals during a particular vigilance task involving the detection of a brief pause in the movement of a clock hand. In order to measure the false alarm probability, Ss were required to make a decision once every five sec. as to whether or not there had been a signal in the previous five sec. In this paper Ss were required to respond as soon as they saw a signal, and it was assumed that the decision interval was the signal duration. The thirty-fold change in assumed decision interval produced very little change in the decrement in d' during the run. It is therefore concluded that the length of the assumed decision interval was not a critical factor in determining changes in d' during the continuous clock task., Pub. in Canad. J. Psychol./Rev. Canad. Psychol. v19 n2 p111- 7 1965 (Copies available only to DDC users).

Variability of 6 Ss in accuracy of reproducing angles from 15 degrees to 90 degrees relative to a horizontal or vertical reference was significantly related to angles, Ss, and references., Reprint from Perceptual and Motor Skills, 18,pp. 231-234, 1964. (Copies not supplied by DDC)

Auditory-detection data presented by Norman (J. Acoust. Soc. Am. 35, 1432 (1963)) are shown to be compatible with the continuous model of signaldetectability theory and not to require the assumption of a low threshold.

Taylor's psychophysical theory of figural aftereffects was used to predict the effect of changes in illumination of inspection and test fields on the amount and the rate of decay of the rotary motion after-effect. As predicted, the brighter inspection disc produced more after-effect, while the brighter test disc produced a smaller and faster-decaying after-effect., Reprint from Perceptual and Motor Skills, 18, pp.885-888, 1964. (Copies not supplied by DDC)

Contents: Apparatus and techniques; Corneal reflection and photography; Electro-oculography and electromyography; Optical levers; Stabilized images; Review and general interest articles.

The purpose of the present experiment was to determine the effect of knowledge of results (KR) when introduced separately from any change in motivation. That is, the object was to determine how much of the improvement reported by Shvarts is due to a learning process specific to the stimulus used, and how much is due to a general excitation of cerebral centres, which according to Shvarts, transfers to the discrimination of other stimuli. The following changes in the procedures described by Shvarts were made. First, KR was intruduced some time after the effect of the motivation variable had been measured. These two variables were confounded in Shvarts' study. Secondly, to distinguish training effects from motivation effects, the level of discrimination was determined independently on a Landolt ring before and after the experiment, in which the training stimulus was a letter E. (Author), Reprint from Perceptual and Motor Skills, 18, pp. 505-508, 1964. (Copies not supplied by DDC)

The three experiments reported here were tests of the effects of four variables upon the perception of the postural upright following body tilt in a forward or backward direction. The four variables studied were; (1) the degree of initial tilt, i.e., the degree to which the subject was tilted before being moved toward the vertical, (2) the time held at initial tilt, (3) the direction of initial tilt, and (4) the angular velocity of return. The fourth variable investigated in the present experiments, velocity of return, had not been evaluated before, nor had any one of the other three variables been studied systematically in the sagittal plane. Immediately bearing on the present report are certain studies dealing with the non-visual perception of the upright, most of which were conducted using lateral tilt. Briefly these reveal that: (a) the error of judgment of the upright is directly determined by the degree of initial tilt, increasing as an underestimation of the upright as the magnitude of initial tilt increases. (b) the error of judgment, either as an underestimation or an over-estimation of the vertical, does not differ significantly for the two directions of initial tilt within any one plane. (c) the error of underestimation of the vertical increases as the time held at the initial tilt increases.

The variations in the real-ear sensitivity of a circumaural earphone due to individual differences in the acoustical impedance of the ear were determined. The results indicated that between-subject variances were significant in the one-third octave bands between 800 and 2500 c/s. At higher frequencies the experimental error of the measurements increased so that between-subject variances, although larger than the mid-frequency values, were not statistically significant. (Author)

Observers judged the slant and shape of a circle, a rectangle and a triangle binocularly under reduced viewing at 0 to 15, 30, 45, and 60 degrees geometric slant. In Exp. I they drew shape with drawing size unrestricted (Draw I) and matched shape with the horizontal axes of 14 comparison shapes constant (Match I). In Exp. II, a different group drew shape by the method of Draw I and with the horizontal axis of the drawing constant (Draw II) and matched shape with the areas of 14 compaison shapes variable (Match II). Slant was underestimated. Draw I and Match I produced about the same overall constancy in Exp. I, Draw I and Match II about the same in Exp. II. Draw II produced more constancy than Draw I and Match II in Exp. II. There was more constancy for the rectangle than for the circle and triangle. The results were contrary to the view that drawn shape is confounded with implicitly registered slant and were inconclusive for the invariance hypothesis. (Author)

Three Os, highly trained in observing visual phenomena, viewed a pair of Julesz Stereo Random Brightness Fields presented alternately to the same eye. Under no circumstances was there any report of stereoscopic depth arising from this mode of presentation. This finding contradicts recent reports of monocular stereoscopy obtained by alternately presenting both halves of a stereo pair to the same eye. It is concluded that impressions of depth gained in this way are not due to stereopsis but to the presence of monocular depth cues in the stimuli. Stereoscopic stimuli, such as Random Brightness Fields, which contain no monocular depth cues, do not give rise to the perception of depth. (Author)

24 Os viewed a rectangle and a triangle binocularly under reduced viewing conditions. The forms were shown in the frontal-parallel plane and at slants of 15, 30, 45, and 60 degrees in random, increasing and decreasing order of angles. Os judged shape by matching and by drawing. There was more constancy for decreasing order than for increasing order. The results for random order were inconclusive. The differences between the indices for drawing and matching were, in general, not significant. The rectangle produced more constancy than the triangle, especially at large slants. The series effect was contrary to prediction based on Helmholtzian and Gestaltist interpretations of the relation between phenomenal slant and phenomenal shape and was interpreted as consistent with adaptation-level theory on the assumption that the focal stimuli affected responses more than the residual stimuli. (Author)

The experiments show that there is a very large subject-to-subject variation in the time until onset of shivering and the time until development of severe continuous shivering. These times are increased by increasing the percentage of oxygen in the inspired gas mixture. The mechanism of the effect of oxygen on the shivering response requires further clarification. (Author)

The effect of intraperitoneal administration of aminooxyacetic acid and hydroxylamine on oxygen poisoning in rats, as measured by convulsions and deaths, was investigated. Amino-oxygacetic acid was without effect on the number of rats convulsing or dying from exposure to hyperbaric oxygen, although in some cases the number of animals severely convulsing was decreased. Hydroxylamine influenced the degree of oxygen poisoning, the direction of the change depending on the time between administration of the compound and the exposure of the animal. When the time interval was 5 min hydroxylamine enhanced oxygen poisoning, but when the interval was 60 min the amine reduced the toxic effects of oxygen at high pressure. This protection was maximal in the animals which had convulsed following the administration of hydroxylamine before being exposed to hyperbaric oxygen. The significance of the present findings is discussed with respect to theories put forward to account for oxygen poisoning. (Author), Pub. in Journal of Neurochemistry v12 p663-9 1965 (Copies available only to DDC users).

Results of a study of time sharing and vigilance reported by Wiener, et al. (1964) have been reanalysed from the viewpoint of signal detection theory. The reported decline in probability of detecting a signal is shown to be due entirely to a progressive change in the observers' response criteria and not to a change in the detectability of the signal. In contrast to the original report that time sharing had a non-significant effect on the probability of detecting a signal, the effect on the detectability of the signal is large. The importance of considering detectability rather than detection measures in vigilance studies is stressed. (Author), Pub. in Perceptual and Motor Skills, v20 p1217-21 1965 (Copies not available to DDC or Clearinghouse customers).

Ten mg. of dl-amphetamine sulphate or placebo were given to 56 Ss in three successive runs on a vigilance task requiring detection of a brief pause in the steady movement of a clock hand. Signals occurred at a rate of three a minute. Amphetamine had the same effect on the percentage of signals detected as on the detectability of the signals, as measured by d'. The initial level was unchanged, but the decrement was reduced. No evidence of learning was found in later runs. The effects of amphetamine and knowledge of results were additive. (Author), Pub. in Canad. J. Psychol./Rev. Canad. Psychol. v19 n2 p104-10 1965 (Copies are available only to DDC users).

Test results indicate that, at least in the MuellerLyer figure, it is impossible to infer the relations of large perceived distances from the relations of their component perceived distances, and hence that there is no single functional relationship (e.g., a power law) between perceived and physical distance., Pub. in Perceptual and Motor Skills v20 p1064 1965 (Copies not available to DDC or Clearinghouse customers).

Following unilateral labyrinthectomy or inactivation of one horizontal semicircular canal in cats, a horizontal positional nystagmus was observed when the cat, after ingesting alcohol, was held with the head up or with the head down. This nystagmus was toward the operated ear in the head-up position and away from the operated ear in the head-down position. It disappeared following inactivation of the horizontal canal of the other ear. In cats with both horizontal canals discretely inactivated, there was no horizontal alcohol nystagmus in any position, but the vertical and rotary components of positional alcohol nystagmus were still present. It was concluded that positional alcohol nystagmus is initiated by the action of gravity on receptors of the semicircular canals. No conclusion could be drawn concerning the site or mechanism of the action of alcohol. (Author), Pub. in American Journal of Physiology v208 n6 p1065-70 Jun 1965. (Copies not available to DDC or Clearinghouse customers).

Groups of 24 Os estimated the slant of a circle and a rectangle (Groups I, II, and III) or a circle and a square (Group IV) by setting a tilt-rod. The forms were viewed at 45 degrees slant, monocularly and binocularly, with fixed head, under reduced conditions. Exposure durations were: for Groups I, II, and IV, 5, 4, 3, 2, and 1 sec., imposed in descending order; and for Group III, five 3-sec. exposures. Groups I and III left the tilt-rod at the response setting, and Groups II and IV returned it to vertical, after each response. With reduced exposure, over-all estimates of slant decreased for the response setting (Group I), but decreased less (Group IV), or did not change significantly (Group II) for the vertical setting. The difference between the estimates for the circle and rectangle or square increased with reduced exposure time due mainly to decrement for the angular forms. The discussion relates the over-all result to an anchor effect of tilt-rod position, and the trend difference for form to differential salience of projective outline distortion and convergence. (Author), Pub. in Perceptual and Motor Skills v20 p481-90 1965 (Copies not available to DDC or Clearinghouse customers).

It was hypothesized that the speed and direction of movement are monitored by proprioceptive feedback and that extent is edetermined by integrating the rate signals in time (Gibbs, 1954). Consideration of analogous servo mechanisms leads to the following predictions that were tested and confirmed (p < 0.01) in tests using 6 female and 4 male Ss. Input data from vision or proprioception alone or from both senses will produce rapid, primary adjustments of equal accuracy. Terminal accuracy was measured to show that the end-points of most residual errors lie in a limited zone of clear central vision, as required by hypotheses. Various previous estimates alleging gross inaccuracy of proprioceptors (Ludvigh, 1952; Crawford, 1960) are shown to be erroneous and irrelevant. (Author), Pub. in Perceptual and Motor Skills v20 p433-42 1965 (Copies not available to DDC or Clearinghouse customers).

The removal of the posterior part of the pituitary gland in the rat leads to an elevation in blood pressure. The production of an anterior-posterior pituitary imbalance in hypophysectomized animals by the administration of certain hormones of target glands influenced by the anterior pituitary (thyroxine, testosterone, cortisone (TTC) also produces an increase in mean arterial blood pressure. In the intact animal, too, the administration of the hormones of the target organs (TTC) will lead to an elevation of blood pressure, and 1 week after the cessation of this treatment the blood pressure is as high or higher than at the end of the administration period. Administration of anterior pituitary hormones TSH, LH, and ACTH both in hypophysectomized and in intact rats also produced elevations in blood pressure. It is concluded that an imbalance between the influences of the anterior and posterior parts of the pituitary gland can lead to a significant elevation in blood pressure., Pub. in Canadian Journal of Physiology and Pharmacology v43 p269-78 1965 (Copies available only to DDC users).

Two experiments were carried out to determine the functional relation between the critical flicker frequency (CFF) of two identical intermittent targets, binocularly superimposed, and the phase difference between the targets. Binocular CFF is a monotonic decreasing function of phase difference, positively accelerated for phase differences between 0 and 180 degrees, and negatively accelerated for phase differences between 360 and 180 degrees. It is postulated that the results can be accounted for by assuming the existence of something akin to the 'isodynamic' cells of Cajal, and that more weight is attached to the input to these cells from one eye than from the other. (Author), Pub. in Canadian Journal of Psychology v19 n1 p47-55 1965 (Copies available only to DDC users). Abstract in French and English.

It is suggested that perceived distance is a function of behaviour that is quantitatively adjusted to the distances of objects. This behaviour is conditioned to compound stimuli whose components include changes of stimulation due to movement. If some of the cues, and particularly those that depend on movement, are eliminated experimentally, there is a quantitative decrease in the behaviour that tends to be evoked, with a consequent shrinkage in perceived distance. This accounts for the common finding that perceived distance is a negatively accelerated increasing function of distance. Perceived size is a function of behaviour quantitatively adjusted to the dimensions of objects. If this behaviour can be evoked by objects at a distance we get size constancy. In this case the cues include those that are conditioned to distance responses, and the result is size-distance invariance. This invariance is disrupted by cue reduction. For example, elimination of distance cues dependent on motion results in increasing overestimation of size as distance increases. Two size illusions are explained in terms of the theory. (Author), Pub. in Candian Journal of Psychology v19 n1 p1-14 1965. (Copies available only to DDC users). Abstract in French and English.

Immediate recall of sets of digits, letters, and colour or shape names presented aurally resembled recall of visual material in the effects of material and message length, but more items were recalled when the messages were presented faster, in contrast to visual presentation. Vocal rehearsal during presentation reduced recall. Ten Ss were tested for each comparison. (Author), Pub. in Canadian Journal of Psychology v18 n4 p292-303 1964 (Copies available only to DDC users).

Four experiments were conducted comparing the effect of message length on the recall of simple and mixed messages of digits, letters, colors, and shapes, presented visually. (Thirty-five housewives served as S2). The total correct recall was inversely related to the message length, with slope independent of composition but with intercept determined by the materials presented. The amount lost due to the second kind of material in a message was related to the time taken to read this material. (Author), Pub. in Journal of Verbal Learning and Verbal Behavior (U. S.) v3 n4 p300-08 Aug 1964 (Copies not available to DDC or Clearinghouse customers).

Data recently published by Graham provide a new test of a theoretical equation for the amount of displacement in a simple figural after-effect, for the condition in which the acuity for the inspection figure is varied without alteration in the spatial relationships of the inspection and test figures. (Author)

When intact rats are cooled, the blood pressure is well maintained down to a body temperature of 22 C, below which it rapidly falls. When hypophysectomized rats are cooled the reduction in blood pressure bears a linear relation to the body temperature. The infusion of Pitressin into hypophysectomized animals during the cooling procedure restores the blood pressure-body temperature relationship to that seen in intact rats. This occurs whether or not the renal vessels are ligated and hence appears to be independent of renal factors. However, when the kidneys are exteriorized and warmed and, at the same time, Pitressin is infused into the hypophysectomized cooled rats, there is an excellent maintenance of blood pressure at the lower body temperatures, the blood pressure being 110 mm Hg when the body temperature is 12 C. Infusions of angiotensin II and of renin also are effective in maintaining blood pressure in hypothermic hypophysectomized animals. This effect of renin is not influenced by exteriorizing and warming the kidneys, hence the enhancement of the effect of pitressin by this procedure is not a consequence of the warming alone. Warming the exteriorized kidneys may release some factor or cause some change which, in the presence of Pitressin, effectively maintains blood pressure at low body temperatures. (Author)

Plasma and liver cholesterol levels were compared in male Wistar rats kept at environmental temperatures of 2 and 23 C on various dietaryyregimens. Cold exposure had little or no effect on the tissue cholesterol levels provided the diet contained appreciable amounts of choline and inositol, the only statistically significant change observed being a small difference in the liver cholesterol concentration in rats maintained on a cholesterol-free diet. A choline- and inositol-deficient diet produced a hypocholesterolemic effect in rats at 23 C but this effect was counteracted by exposing the rats to a cold environment. The possible significance of this observation with regard to the biochemical defect in choline deficient fatty livers is discussed. (Author), No Foreign.

Gamma-aminobutyric acid (GABA) is found in appreciable amounts in mammals only in the central nervous system, where it is believed to play important roles in oxidative metabolism and in the regulation and transmission of nerve impulses. GABA in the brain is formed from glutamic acid by decarboxylation and is catabolized by a transamination reaction with alphaketoglutaric acid, the latter enzyme forming part of the well-known GABA shunt pathway. The level of GABA in the brain may therefore be regulated by varying the relative reaction rates of these two enzyme systems referred to as GAD and GABA-T respectively. Since no data are available concerning the relative sensitivity of GAD and GABA-T to oxygen the present investigation was initiated to study this aspect of the problem. (Author), Reprint from Canadian Jnl. of Physiology and Pharmacology, 42, pp. 277-279, 1964. (Copies not supplied by DDC)

The discrete surgical inactivation of all six semicircular canals were found to be equivalent to bilateral labyrinthectomy in eliminating motion sickness in dogs, even though the otolith organs remained functional. Inactivation of fewer than six of the canals reduced the susceptibility of dogs to motion sickness, but to a lesser degree than did inactivation of all six canals. These findings are consistent with the theory that stimulation of the semicircular canals causes motion sickness. Rotatory tests of the horizontal and vertical semicircular canals and tests of an otolith reflex, preoperatively and postoperatively, yielded information about the basic functions of the semicircular canals and confirmed that the surgical procedures had accomplished their objectives without unintended damage to other vestibular receptors. (Author)

This experiment attempted to determine the effect on retention of varying the amount of information contained in knowledge of results (KR) and the cues inherent in a task. The literature suggests that precision of KR affects acquisition but not retention (McGuigan, 1959). Previous attempts to measure the effect of KR precision did not, however, vary the degree of information contained in the task itself. There is evidence that, with sufficient information in the task, retention is better when the KR precision is increased (Lavery, 1964). Thirty-six housewives from 21 to 35 yr. of age were Ss; 12 were trained under each gain condition for 120 trials (with KR) and then given 80 retention trials (without KR) on the first day and 120 additional retention trials 1 wk. later. The results showed no difference between groups on the first 80 retention trials on Day 1. The 2:1- and 1:1-ratio groups were clearly superior, however, to the 0.5:1-ratio group on the second retention series (F = 7.06 and 4.45, respectively; df = 1/22). Retention can be influenced by precision of KR if the degree of information in the task is great enough. Work is now under way to find out how this relationship depends upon inherent task information. The possibility of using this task to study retroactive inhibition is also being investigated., Pub. in Perceptual and Motor Skills (U. S.) v19 p626 1964 (Copies not available to DDC or Clearinghouse customers).

The effect of cold exposure and choline deficiency on the levels of liver lipids of male albino rats was studied at four dietary intakes of methionine (20-100 mg per rat per day). After exposure of the animals to cold (2-3 degrees C) for a 10-day period, the liver lipids were analyzed for total and free cholesterol, phospholipid, and triglyceride. In choline-fed animals, cold exposure did not affect triglyceride or total cholesterol levels but elevated phospholipid and free cholesterol and decreased ester cholesterol. The increase in phospholipid levels occurred at all methionine intakes with the changes in the cholesterol fractions occurring only at methionine intakes >40 mg per day. In choline-deficient rats, there was evidence that the lipotropic action of cold exposure was related to dietary methionine intake. At methionine intakes <60 mg per rat per day, fatty infiltration of the livers of the choline-deficient cold-exposed rats occurred, as evidenced by the accumulation of triglyceride and ester cholesterol. Concomitantly, phospholipid levels decreased. The data suggest that cold increases the capacity of the animal to synthesize choline from endogenous sources. (Author), Pub. in Canadian Journal of Physiology and Pharmacology v42 p769-77 1964 (Copies available only to DDC users).

The results of a previous experiment showed that a bilateral kinesthetic difference did not obtain when tactual-kinesthetic judgments were made with the left and right hands. The present experiment was designed to eliminate the possible contribution of visual and kinesthetic figural aftereffects to the directional bias of errors. Results indicate that performance was equivalent with the left and right hands. (Author), Pub. Perceptual and Motor Skills v20 p1147-8 1965 (Copies not available to DDC or Clearinghouse customers).

Ten subjects were used in comparative tests of pressure and free-moving control levers in a task of pursuit tracking, using a positional control system with zero lag. Pressure control was superior to that free-moving lever at the p<0.01 level of confidence. Data are provided on the subjects' delays in responding to a step change of uniform velocity. (Author), Pub. in Ergonomics v8 n1 p23-9 Jan 1965 (Copies available only to DDC users). Abstract in French, German and English.