A Further Experiment on the Discrimination of Open and Closed Shapes by Rats

1964 ◽  
Vol 16 (3) ◽  
pp. 268-271
Author(s):  
N. S. Sutherland
Keyword(s):  
Visual Discrimination ◽  
Present Experiment ◽  
Previous Experiment ◽  
Strong Preference ◽  
Different Shapes ◽  
Open Shape

In a previous experiment on the visual discrimination of open and closed shapes by rats (Sutherland, Carr, and Mackintosh, 1962) it was found that (1) at the beginning of training the animals exhibited a strong preference for the more open shape; (2) shapes differing in their horizontal projections only were more discriminable than shapes differing in their vertical projections only. The present experiment is a replication of the earlier one using different shapes and different apparatus. The first result was fully confirmed and some confirmation was obtained for the second, although late in training the differences between groups trained with shapes differing on opposite projections were not statistically significant.

The Effect of Operating Lamps on the Protected Area of a Unidirectional Down Flow (UDF) System

2016 ◽  
Vol 10 (3) ◽  
pp. 40-50 ◽  
Author(s):  
A. A. L. Traversari ◽  
C. Bottenheft ◽  
R. Louman ◽  
S. P. M. van Heumen ◽  
J. Böggemann
Keyword(s):  
Protected Area ◽  
Airborne Particles ◽  
Operating Theater ◽  
Degree Of Protection ◽  
Early Entry ◽  
Different Shapes ◽  
Open Shape ◽  
Positive Effect

Background: Operating lamps are often seen as the most disruptive factors within the protective area in the operating theater (OT). The effect of the operation lamps (with different shapes) should be demonstrated in an OT by trial, since research on the effects of the lamps is still limited. Objectives: The main aim of this study was to determine the effects of a skirt, different lamps, and the position of the lamp on the protected area. Methods: The concentration of airborne particles was measured under different circumstances, in order to determine the size and quality of the protected area. This entrainment/segregation test is based on the deliberate and controlled emission of particles outside the zone that is protected. Findings and Conclusions: The degree of protection (DP) at the center of the protected area was higher for the case with the skirt. This skirt stimulates more down flow and prevents the early entry of particles into the protected area. It can also be concluded that Lamp Y, due to its open shape, has the most positive effect on the DP at the center. It has also been shown that the position of the lamp has an effect on the protected area.

Quantitative Tactual-Kinesthetic Judgment

1965 ◽  
Vol 20 (3_suppl) ◽  
pp. 1147-1148 ◽  
Author(s):  
A. V. Churchill
Keyword(s):  
Present Experiment ◽  
Previous Experiment ◽  
Directional Bias ◽  
Left And Right

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.

Hemispheric Competence and Perceptual Confusability

1983 ◽  
Vol 35 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Justine Sergent
Keyword(s):  
Visual Field ◽  
Opposite Direction ◽  
Present Experiment ◽  
Significant Interaction ◽  
Left Visual Field ◽  
Previous Experiment ◽  
Right Visual Field ◽  
Methodological Procedures ◽  
Visual Field Superiority ◽  
Exact Replication

Hemispheric competence in performing easy and difficult letter classification was examined in an exact replication of a previous experiment by Jonides (1979). The present experiment failed to confirm Jonides's finding of right visual field advantage in conditions of perceptual confusability and left visual field superiority when the stimuli were easily discriminable. The results showed a trend in the opposite direction, but no significant interaction. This divergence is discussed with respect to existing evidence and methodological procedures.

Short-Term Memory for Colors and Color Names in the Absence of Vocalization

1984 ◽  
Vol 59 (1) ◽  
pp. 263-266 ◽  
Author(s):  
Charles K. Allen
Keyword(s):  
Present Experiment ◽  
Short Term Memory ◽  
Previous Experiment ◽  
Verbal Label ◽  
Stimulus Presentation ◽  
Proactive Inhibition ◽  
Short Term ◽  
Term Memory ◽  
No Release ◽  
Encoding Strategy

In a previous experiment, Allen found no release from proactive inhibition using the Brown-Peterson procedure in a group who were shifted from recalling colors to recalling the names of colors. The lack of release suggests that colors and color names are encoded in similar ways. It was argued that the similarity of encoding might have been caused by the procedure of requiring the subjects to say out loud the names of the colors at the time of stimulus presentation and recall. In the present experiment, a procedure was devised that eliminated the need for verbalization of the colors. The same pattern of results was obtained, namely, release from proactive inhibition in the group shifted from recalling color names to colors but not in the group shifted in the opposite direction. It was concluded that if subjects encode colors as a verbal label, then this encoding strategy is not caused by the procedure of requiring the subjects to verbalize the colors.

scholarly journals Further experiments on the behaviour of single crystals of zinc subjected to alternating torsional stresses

1930 ◽  
Vol 127 (805) ◽  
pp. 453-479 ◽  
Keyword(s):  
Single Crystal ◽  
Normal Stress ◽  
Single Crystals ◽  
Basal Plane ◽  
Present Experiment ◽  
Previous Experiment ◽  
Relative Orientation ◽  
Normal Stresses ◽  
Slip Direction ◽  
Twinning Plane

Object of Experiment .—From the results of a previous experiment on a single crystal of zinc, it was concluded that the formation of twins in zinc occurred on planes of the 101 ˉ 2 type and that the particular operative twinning plane (of the six available) was determined chiefly by the direction of slip on the original basal plane and possibly, to some extent, by the relative magnitudes of the normal stresses on the possible twinning planes. In this previous experiment the orientation of the crystal was such that slip on the original basal plane occurred in one direction only and one pair of complementary twins only was observed. From the results it was predicted that if a test were made on a crystal of suitable relative orientation of the crystallographic and straining axes such that all three slip directions became operative, then the operative twinning planes should change with the slip direction. The present experiment was planned in order to test this prediction. Again, in the previous experiment, of the two possible pairs of complementary twinning planes associated with any one slip direction, it appeared probable that the choice of the operative pair was influenced by considerations of normal stress on the twinning plane. The present experiment would, it was hoped, throw further light on this aspect of twinning.

Feeding sorghum stover to Ethiopian, yearling cattle: effects of amount of stover offered and cottonseed cake supplement on intake and growth

1992 ◽  
Vol 1992 ◽  
pp. 197-197
Author(s):  
E L K Osafo ◽  
E Owen ◽  
A N Said ◽  
M Gill ◽  
A B McAllan ◽  
...  
Keyword(s):  
Present Experiment ◽  
Dry Matter ◽  
Previous Experiment ◽  
Cottonseed Cake ◽  
Growth Responses

The experiment forms part of a study to investigate methods of improving the use of sorghum stover as a feed for ruminants in Ethiopia. A previous experiment (Osafo, Owen, Said, Gill and McAllan, 1991) showed that intake and growth of cattle were improved when the amount of sorghum stover offered was increased from 25 to 50 g dry matter [DM] per kg weight [M] daily [d], and when the stover was offered unchopped rather than chopped. The present experiment investigated the intake and growth responses of yearling cattle to increasing the amount of stover offered, and to supplementing with cottonseed cake.

The effects of formic acid and rate of drying in the field on the efficiency of conservation and on energy and protein retention of growing steers given grass silage

1984 ◽  
Vol 1984 ◽  
pp. 114-114
Author(s):  
E. Charmley ◽  
C. Thomas
Keyword(s):  
Formic Acid ◽  
Present Experiment ◽  
Dry Matter ◽  
Previous Experiment ◽  
Animal Production ◽  
Protein Retention ◽  
Grass Silage ◽  
65 H

In a previous experiment the wilting of herbage prior to ensiling had no effect on the efficiency of utilisation of silage for animal production. The direct-cut material was conserved with formic acid and wilting was relatively prolonged (65 h) to achieve an increase in dry matter (DM) content of 226 g DM/kg. The objective of the present experiment was to examine the effect of formic acid with direct-cut silage and the rate of wilting of herbage on losses in conservation and on energy and protein retention by growing steers.

The Time-Course of Preparation with Regular and Irregular Foreperiods

1968 ◽  
Vol 20 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Paul Bertelson ◽  
FrançOise Tisseyre
Keyword(s):  
Present Experiment ◽  
Time Course ◽  
Previous Experiment ◽  
Warning Signal ◽  
Temporal Information ◽  
Visual Signal ◽  
The Subject

A previous experiment (Bertelson, 1967) had shown that the temporal information brought by a warning signal affected RT even after very short foreperiods (FPs). The present experiment was carried out to examine whether this result was contingent on the predictability of the FP. After a 5 sec. waiting delay, the subject heard a warning click which was followed after a predictable (regular procedure) or unpredictable FP (irregular procedure) by the visual signal calling for a choice reaction. The range of FPs was 0–300 msec, again. The time course of the adjustments triggered by the click was found to be similar under both procedures. The main conclusion is that a shift from preparation to reaction can occur at any time and need not be programmed before preparation is started.

Topological Structure in the Perception of Apparent Motion

Perception ◽  
1985 ◽  
Vol 14 (2) ◽  
pp. 197-208 ◽  
Author(s):  
Lin Chen
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Apparent Motion ◽  
Topological Structure ◽  
Strong Preference ◽  
Topological Invariants ◽  
Plastic Deformations ◽  
Central Figure ◽  
Different Shapes

Not only translations and rotations, but also intriguing ‘plastic deformations’ are observed in apparent motion. What kinds of invariants does the visual system depend on during these transformations to determine that two figures of different shapes nevertheless represent the same object? Experiments are reported in which seven pairs of stimuli with topological differences were used. The evidence suggests that topological invariants may be used in the perception of apparent motion. In spite of variations in other factors, such as brightness, spatial frequency, terminators, etc, subjects displayed a strong preference for motion from a central figure to a figure with the same topological invariants. The results emphasize the importance of topological structure in figure perception.

Effect of Head Movement in Visual-Kinesthetic Localization

1969 ◽  
Vol 28 (3) ◽  
pp. 785-786 ◽  
Author(s):  
A. V. Churchill
Keyword(s):  
Head Movement ◽  
Present Experiment ◽  
Previous Experiment ◽  
Visual Localization

The results of a previous experiment showed that visual estimates of kinesthetic localization and kinesthetic estimates of visual localization were equally accurate, but with errors in opposite directions, when S was free to move his head. The present experiment was designed to measure the contribution of head movement to the accuracy of visual and kinesthetic localization. Results indicate that performance is equivalent under the “free-head” and “fixed-head” conditions.

Sign in / Sign up

Export Citation Format

Share Document