The Psychophysics of Retrospective and Prospective Timing

Perception ◽  
1988 ◽  
Vol 17 (3) ◽  
pp. 297-310 ◽  
Author(s):  
Scott W Brown ◽  
D Alan Stubbs

In two experiments, different groups of subjects heard four musical selections and then estimated the duration of each selection. Some groups made retrospective time estimates while others made prospective estimates. In both experiments, analyses of the psychophysical relation between perceived and actual duration showed that the slopes of straight-line fits were flatter and accounted for a smaller proportion of the variance under retrospective as compared with prospective conditions. In addition, in experiment 1, retrospective subjects were less accurate in rank ordering the selections from longest to shortest. There was also a serial-order effect, with selections estimated longer when they occurred early in the sequence. In experiment 2 the slopes decreased as the selections in a series became longer. Both retrospective and prospective estimates also exhibited a context effect, in that estimates of a given selection were influenced by the relative durations of the other three selections in the series. The results on inaccurate retrospective judgments raise questions about prior research on stimulus factors and retrospective timing. However, similarities under retrospective and prospective conditions suggest that timing under these conditions, although different in some respects, reflects a similar process.

2013 ◽  
Vol 36 (3) ◽  
pp. 293-294 ◽  
Author(s):  
Elias L. Khalil

AbstractAlthough the quantum probability (QP) can be useful to model the context effect, it is not relevant to the order effect, conjunction fallacy, and other related biases. Although the issue of potentiality, which is the intuition behind QP, is involved in the context effect, it is not involved in the other biases.


1878 ◽  
Vol 28 (2) ◽  
pp. 633-671 ◽  
Author(s):  
Alexander Macfarlane

The experiments to which I shall refer were carried out in the physical laboratory of the University during the late summer session. I was ably assisted in conducting the experiments by three students of the laboratory,—Messrs H. A. Salvesen, G. M. Connor, and D. E. Stewart. The method which was used of measuring the difference of potential required to produce a disruptive discharge of electricity under given conditions, is that described in a paper communicated to the Royal Society of Edinburgh in 1876 in the names of Mr J. A. Paton, M. A., and myself, and was suggested to me by Professor Tait as a means of attacking the experimental problems mentioned below.The above sketch which I took of the apparatus in situ may facilitate tha description of the method. The receiver of an air-pump, having a rod capable of being moved air-tight up and down through the neck, was attached to one of the conductors of a Holtz machine in such a manner that the conductor of the machine and the rod formed one conducting system. Projecting from the bottom of the receiver was a short metallic rod, forming one conductor with the metallic parts of the air-pump, and by means of a chain with the uninsulated conductor of the Holtz machine. Brass balls and discs of various sizes were made to order, capable of being screwed on to the ends of the rods. On the table, and at a distance of about six feet from the receiver, was a stand supporting two insulated brass balls, the one fixed, the other having one degree of freedom, viz., of moving in a straight line in the plane of the table. The fixed insulated ball A was made one conductor with the insulated conductor of the Holtz and the rod of the receiver, by means of a copper wire insulated with gutta percha, having one end stuck firmly into a hole in the collar of the receiver, and having the other fitted in between the glass stem and the hollow in the ball, by which it fitted on to the stem tightly. A thin wire similarly fitted in between the ball B and its insulating stem connected the ball with the insulated half ring of a divided ring reflecting electrometer.


2013 ◽  
Vol 834-836 ◽  
pp. 1290-1294
Author(s):  
Xin Qin Liu

Mechanicalmethods were employed to study the motion and force transmission performance ofa kind of connecting rod slider mechanism with a curved edge driving component.The deduction methods and the computation formulae of the slider displacement,velocity, acceleration and the executive force gain coefficient were given.Considering two cases of the driving components with straight line edge andexponential function edge, the numerical examples was computed respectively,the results show that the former one is suitable for the force transmission andcan be used in the grip design and the other one is suitable for the motiontransmission which can be used in the fast moving mechanism


1851 ◽  
Vol 1 (1) ◽  
pp. 40-46
Author(s):  
Edwin James Farren

The term scholar, as current in the English language, has two extreme acceptations, tyro and proficient; or what the later Greeks fancifully termed the alpha and omega of acquirement. If we attempt to trace the steps by which even the adult student of any especial branch of professional or literary knowledge has fairly passed the boundary defined by the one meaning in passing on to that position denoted by the other, it will commonly be found, that in place of that lucid order, that straight line from point to point, which theory and resolve generally premise, the real order of acquirement has been desultory—the real line of progression, circuitous and uncertain.


2010 ◽  
Vol 69 (3) ◽  
Author(s):  
W. F. Harris

For a dioptric system with elements which may be heterocentric and astigmatic an optical axis has been defined to be a straight line along which a ray both enters and emerges from the system.  Previous work shows that the dioptric system may or may not have an optical axis and that, if it does have one, then that optical axis may or may not be unique.  Formulae were derived for the locations of any optical axes.  The purpose of this paper is to extend those results to allow for reflecting surfaces in the system in addition to refracting elements.  Thus the paper locates any optical axes in catadioptric systems (including dioptric systems as a special case).  The reflecting surfaces may be astigmatic and decentred or tilted.  The theory is illustrated by means of numerical examples.  The locations of the optical axes are calculated for seven optical systems associated with a particular heterocentric astigmatic model eye.  The optical systems are the visual system, the four Purkinje systems and two other nonvisual systems of the eye.  The Purkinje systems each have an infinity of optical axes whereas the other nonvisual systems, and the visual system, each have a unique optical axis. (S Afr Optom 2010 69(3) 152-160)


An attempt is made in this paper to gain the flexibility of movement of robots around the boundary of the workspace, where in many robots are moving at a time in the presence of the static curved obstacles. The boundary of the workspace may be a straight line or curve shaped. The obstacle may be polygonal or curved shaped. A program is developed for the motion of the multiple robots to move from its origin location to the desired location without colliding with the boundary, the other moving robots and the static obstacles. The program is based on the curve fitting technique. As and when the robot comes close to the curved boundary or curved barrier, it will trace the path formed by the curve equation using the technique of curve fitting. Since there are multiple robots, the path planning ensures the robots to reach their targets in minimum time. During tracing the path, if more than one robot is following the same path, priority is assigned to such robots. Multiple robots finds application in assembly operations, medical supplies and meals to patients, disinfecting the rooms for patients etc.


Author(s):  
Toplica Stojanović ◽  
Slobodan Goranović ◽  
Aleksandar Šakanović ◽  
Darko Stojanović

In order to determine at which level is the specific performance and technical and tactical efficiency of young players of different level of competition, and whether the level of competition can be an indicator of level differences of these abilities, a research was conducted on the sample of young football players aged 14 to 16 from the eight clubs, half of them competing in the higher and the other half in the lower level of competition. A sample of measuring instruments consisted of 13 tests for evaluation of five factors of specific endurance: starting endurance, stamina in maintaining the shallow formation, endurance during fast dribbling, ball pressing endurance, and evaluation of technical and tactical efficiency of football players. The results of the research showed that the young players of higher level of competition had significantly greater technical and tactical efficiency, as well as specific performance in tests which included curvilinear movement and dribbling, as well as control and passing the ball in motion, but the difference is not recorded with straight-line movements and sprints.


1805 ◽  
Vol 5 (2) ◽  
pp. 271-293

It is now generally understood, that by the rectification of a curve line, is meant, not only the method of finding a straight line exactly equal to it, but also the method of expressing it by certain functions of the other lines, whether straight lines or circles, by which the nature of the curve is defined. It is evidently in the latter sense that we must understand the term rectification, when applied to the arches of conic sections, seeing that it has hitherto been found impossible, either to exhibit straight lines equal to them, or to express their relation to their co-ordinates, by algebraic equations, consisting of a finite number of terms.


1967 ◽  
Vol 25 (1) ◽  
pp. 189-202 ◽  
Author(s):  
Kristian Holt-Hansen

An attempt was made to present an electronic model of the neural correlate to the experiences of straightness and circularity on the basis of experimental data. Two sets of experiments were described. In one Ss had numerous kinds of experience when the stimulus object was a straight line or a circle. These experiments demonstrated a close relationship between a straight line and a circle in experience. The other set of experiments consisted of adjusting the electric voltages fed into a cathode ray oscilloscope so that the displays on the screen corresponded closely to some of the experiences reported by subjects in the first set of experiments. A plausible working hypothesis was put forward on the basis that the electronic functions underlying the working of a cathode ray oscilloscope suggest a close analogy with the brain function underlying the experiences obtained when the stimulus object is a straight line or a circle.


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