AN EXPERIMENT WITH TIME PERCEPTION

EFFECT OF COLOR AND STIMULUS ANIMATION ON TIME PERCEPTION KARMA GURUNG AND TED JAEGER Westminster College Abstract This study examined the impact of color and stimulus animation on the perception of short term intervals. Grey and yellowish green stimuli were presented in either steady or flickering for a period of 3 or 6 seconds. It is predicted that colored or highly animated stimulus will seem longer time than animated stimulus less movement or no movement. The result showed that the effect of animated stimulus with greater movement had a significant lengthening effect on the perceptual time. There was no significant effect of color on perceived time. This study demonstrates that the perceived time is affected by the amount of movement of things that we see. This may occur because of the effect of stimulus on the magnocellular neurons which detect motion stimuli. Keywords: time, chromatic, achromatic, interval, light, duration, variation, perception, static, motion, flicker EFFECT OF COLOR AND STIMULUS ANIMATION ON TIME PERCEPTION The notion of time dates back to the beginning of everything; evolution, universe and the human civilization. However, Time has remained as one of the most mysterious topics in almost every field of study, even today. Time is mischievous as it has been confusing philosophers, physicists, psychologists and the general public for centuries. One challenge to understanding time is that there is no identifiable stimulus or sensory organ that corresponds to our perception of time. Moreover, the meaning and the existence of time also seem to vary as we go from one discipline to another as following. Physics Physicists have been able to calculate time with such preciseness that they even calculated the speed of light and can predict the planetary motions. Yet, questions such as "Does time exist?" often lead scientists to confusions to whether it does or does not exist. On one hand, the study of time beyond the "Plank Time" suggests that time may not exist in a physical way. On the other hand, Quantum Mechanics requires time. However, General Relativity state that time is relative to the observer and supports the non existence of global time (Craig, 2010). To resolve the issue on the existence of time, in the late 1960s, when physicists John Wheeler and Bryce DeWitt attempted to rewrite Einstein’s equations for gravity in the same way as the quantum theory of electromagnetism had been developed, the symbol of time t completely vanished from the equation (Craig, 2010). In other words, time did not seem to exist according to John and Bryce’s equation (Wheeler-DeWitt equation). According to physics, time may not exist in the physical world. If that is the case, why do we feel constricted to carry some form of clock every day, finish our work in time and if time does not exist, for god’s sake why do we grow? This may lead to the interpretation that time may be more bio-psychological than physical. Biology From the biological point of view, although at first it may seem that biological processes have nothing to do with our notion of time; several biological experiments have shown that there is a strong correlation between the perception of time and pacemakers such as heart beats, metabolism, and body temperature. An interesting demonstration of the biological clock was done by Hoagland (1933). He showed that at higher body temperature, physical activity increased, the biological pacemaker ticked faster. While his wife was sick and was asked to interpret the time, she consistently interpreted a one minute time interval longer as her body temperature increased. A study on alteration of body temperature in rats shows similar results (Shurtleff, Raslear, & Simmons, 1990). Psychology From a psychologist’s point of view, time is an aspect of our perceptual world rather than being a physical condition such as atoms, waves, or dark matter. However, most perceptual experiences are more or less related to some physical stimulus. Since we have a conscious sense of the passage of time, psychologists conclude that it is clearly a perceptual experience. Incorporating the knowledge of the three disciplines, Physics, Biology, and Psychology related to time; we know that in Physics time is the measurement of change, and that in Biology, the sensory organs detect the changes, and that in Psychology the physical stimulus is not always fully or accurately represented in experience. The following illustration gives an example of how the physical world, the biological world, and the psychological world are intertwined to give a sense of how time is perceived. Change (stimulus) --> detection (sensation) --> perception (experience) The above illustration suggests that sensation (detection) of change plays a crucial role in determining perceived duration or time to understand the perpetual flow of time. However, change (stimulus) can only be sensed by sensory organs. Sensory organs play a vital role in the determination of time and the rate of its flow. However, we don’t really know precisely how stimulus variation such as a slow moving body and a fast flickering light (either colored or black and white) can impact our perception of short term interval. On one hand, the parvocellular neurons which are spread throughout retina of an eye are well suited to detect visual details and are responsive to color. On the other hand, the magnocellular neurons are the large bodies with larger cell bodies and receptive fields. The magnocellular neurons are distributed fairly evenly throughout retina and are strongly responsive to moving stimuli and to large over all patterns but not to details. However, they are not color sensitive (Kalat, 1998). In this experiment, we are using yellowish-green color as chromatic stimulus and black & white (grey) as achromatic stimulus to test the effect of ocular stimulus variation in the perception of short term time interval. In addition, Brigner's (1980) experiment, "Effect of perceived brightness on perceived time" shows that when light intensity demarcating a 1-sec. interval was increased, there was an increase in the perceived duration of the interval. The increase in perceived duration remained unaffected whether the intensity of light was increased by perceptual means or physically. The research on “Effect of Color and Stimulus Animation on Time Perception” will further help to give insight on Brigner’s experiment, it will explore how motion and flicker in color and non color stimulus can change the effect of increase in the intensity of light can affect the perception of short term duration. The purpose of this research project is to understand the impact of stimulus variation on the perception of short term intervals. This research project will help to understand how we as human beings perceive time for slow moving objects and colored objects. The hypotheses are that greater stimulus variation leads to a perception of longer time interval for short term stimulus. In addition, the six seconds interval is perceived longer than the three seconds interval and the chromatic stimuli (yellowish green) creates a perceptually longer interval than the achromatic (blackish white) stimuli. Method Participants Twenty participants were tested in the experiment out of which 10 were male and 10 were female. Participants were randomly chosen Psychology students and volunteers ranging from age 18-25 years. Materials Dell computer with Super Lab software and a key board is used for the experiment. Yellowish-green, blackish-white and flickering block images are incorporated to make animation videos. The yellowish-green and blackish-white block videos run at the rate of eight frames per second, and the flickering block image video runs at sixteen frames per second. The animation videos are displayed on the computer screen to the participants will be dealt as optical stimulus for the experiment. Finally, the clock used to make time estimation is a different animation video made under similar principle that runs a yellowish-green irregular block images that runs at a varying rate of frames per second. The spacebar on the dell key board is used as a control to judge interval and to end interval, thus making an estimation of how long one of the yellow-green or black-white stimuli lasted. Design and Procedure The study utilizes a 3 x 2 x 2 design with three levels of stimulus variation a static image (Steady), moving image (Block), or flickering image (Flicker). The variable is crossed with the two time duration, three seconds and six seconds and crossed with two levels of stimuli, chromatic and achromatic (Figure 1). Figure 1 The experiment for each participant is carried out anytime from 2-4 pm on Wednesday or on Thursday. The experiment test is done consecutively from male to female participant on Wednesday and consequently from female to male on Thursday. The participants during the research experiment will observe the variables (static, moving and flickering image videos) either yellowish-green or blackish-white on a computer screen. Each variable is presented to the participant for 3 seconds and then 6 seconds. The participants will then estimate the duration of time taken for each variable by starting and stopping the clock (animation video with irregular block images). Results In conclusion, the t-test value of color motion stimulus was 0.007 and black and white motion stimulus was 0.085. Therefore, the t-test value was significant for color motion stimulus and while the black and white motion stimulus was marginally significant. The result supports our hypothesis that greater stimulus variation leads to a greater perceptual interval of time. Significance Table Color Static 0.350 Color Motion 0.007 Color Flicker 0.130 Black and White Static 0.514 Black and White Motion 0.085 Black and White Flicker 0.210 Discussion Brigner's (1980) study of "Effect of Light Intensity on Time Perception" shows that higher light intensity increases the length of perceptual time. From our study, we now know that stimulus animation can also make significant differences in time estimation. The effect of stimulus in motion was significant since the estimated value of time interval exceeded far greater than the original time interval the stimulus had been exposed. While comparing the effect of stimulus animation in between three seconds and six seconds time intervals the result of the experiment indicates that the longer time interval gives similar effect but in greater amount. The static or steady stimulus had the least amount of effect on the time interval, and was most accurate while estimating the time interval of the stimulus presented. Hence, one could interpret that anything that is static or has the least amount of change could be a better frame of reference for time judgment than any random stimulus in motion. In addition, since greater amount of animated stimulus resulted in longer estimation, this means that when our eyes see greater movements we perceive an event being longer. Reference Brigner, W. L. (1986). Effect of perceived brightness on perceived time. Perceptual & Motor Skills, 63427-430. Chin-Chiuan, L. (2003). EFFECTS OF ILLUMINATION, VIEWING DISTANCE, AND LIGHTING COLOR ON PERCEPTION TIME. Perceptual & Motor Skills, 96(3), 817. James, W.K. (2007). Biological Psychology (9th ed.). Canada: Thomson Learning, Inc. Geddes, L. (2011). The clock in your head. New Scientist, 212(2833), 44. Callender, C. (2010). Is Time an ILLUSION?. Scientific American, 302(6), 58-65.