Experiment on Square-Wave versus Sine-Wave Audiovisual Events - Lab Report Example

Experimental Report Name Institution Course Professor Date Abstract This report presents a visual research experiment on Square-wave vs. sine-wave audiovisual events. The research methodology focuses on illustrating that visual and auditory components may attain a temporal coincidence at audiovisual interaction. The visual search experiment involved temporal modulation of both square and sine wave. The research makes a conclusion that benefits in visual search are attained only when temporal alignment of audiovisual is attained when component signals are transient and synchronized. This leads to a recommendation that transient signals are vital in the overall process of synchrony in order to avoid interactions of unrelated signals. Table of Contents Abstract 2 Title 4 Introduction 4 Hypothesis 5 Method 5 Participants 5 Design 5 Equipment 6 Stimulus 6 Procedure 7 Results 7 Discussion 10 Conclusion 12 References 13 List of Tables Table 1: Averages for the square-wave 8 Table 2: Averages for the sine wave 9 List of Figures Figure 1: Combined bar graph of square and sine waveforms 8 Figure 2: bar graph of the main effect of square waveform 9 Figure 3: bar graph of the main effect of the sine waveform 10 Title Square-wave vs. sine-wave audiovisual events Introduction Most of the events and objects, which occur in our natural environment, are associated with production of sound and light energy, which can be detected by auditory and visual sensory systems (Van der Burg et al., 2010). As such, studies have been conducted, which have evidenced that there is a domination of perception of audiovisual by vision in special tasks while domination for audition occurs in temporal tasks (Thomas, 1941). Nevertheless, this condition is reversible by degrading of information at the context of a dominant sense. Audiovisual integration is perceived to occur when there is a temporal coincident of signals. However, one of the recently conducted studies did not attain any evidence, which indicates that in visual search audiovisual integration occurs at audiovisual events synchronization (Van der Burg et al., 2010). This poses a question on what information is vital for the audiovisual integration to be observed. This experiment had the objectives of finding out how vision could be improved under certain circumstances and whether certain parts of the visual field attain a better performance than others. Since Van der Burg et al. (2010) was able to establish evidence of audiovisual interaction while Fujisaki et al (2006), did not attain success, this paper focuses on attaining the above objectives to identify the gap between Van der Burg et al. (2010) and Fujisaki et al. (2006). Fixation in this experiment depicts the process by which participants were obsessed to an inanimate object and provide a response on the same. Synchronizing represents the situation of causing events in the experiment to have a similar time of operation. On the other hand, modulation indicates the process of regulating and causing events to attain a similar occurrence. On the other hand, events indicate occurrences that took place during the experiment. Hypothesis Hypothesis 1: square-wave modulation leads to attainment of visual search benefits. Hypothesis 2: sine-wave modulation does not yield any benefits in visual search. Hypothesis 2: modulation of signals improves vision and leads to attainment of better performance. In review of the results obtained in this experiment, it is evident that sine-wave modulations have no ability to attain any benefits in visual search for audiovisual synchronization while the square-wave modulations attain benefits in visual search of synchronization of audiovisual events. This illustrates that square-wave and sine-wave benefits are attributed to synchronization of auditory stimulus and the transient luminance event, but not due to amplitude or discrete and continuous variation. Method Participants This experiment included 23 participants where 19 were females while 4 were males. The participants enjoyed a course credit with reference to their participation in this research. Design The stimulus type, which was the independent variable for this experiment was either a square-wave modulation or a sine-wave modulation. The other independent variable was the target visual field location north, south, east, and west. The dependent variable for the experiment was the ability of the participants to accurately detect the target and their reaction time. Reaction time was characterized of the time interval between onset of the display and attainment of the response for this target. Equipment The following apparatus were used in order to run this experiment: PC running E-Prime software, a dark room, standard computer keyboard, Sennheiser headphones, and computer monitor (Mitsubishi Diamond Pro of 1024 × 768 pixel of resolution with a running frequency of 100 Hz at refresh rate). Stimulus A fixation point was predetermined at the center of the screen. Each trial comprised of nineteen luminance-modulating disks. These disks were equidistantly placed on an imaginary circle from the fixation at visual angle of 15 degrees. Each disk had its diameter subtending a 0.5 degrees visual angle. The disk had a luminance variation in the range between 0.1 at minimum to 165 cd/m2 at maximum. Periodic modulation was achieved for each disk at a modulation cycle of 1 second. Each trial comprised of two cycles of modulation. The modulation phases for the disks were different (the disks had different times of attaining their maximum and minimum luminance), but the rate of luminance for disk modulation was the same (1 cycle per second or 1 Hz). Temporary adjacent disks had a phase difference of 50 ms. Individual disks had a maximum luminance at 0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850 & 900 ms. The temporal phases were randomly allocated for each trial at the 19 possible spatial locations. Either a square-wave or sinusoidal wave was attained as the modulation profile for temporal luminance for a given trial. Determination of this occurred randomly for the trials. Each trial indicated a 500 Hz tone, which had a closer resemblance to the visual elements modulation rate. A single visual element was used to synchronize the tone of each phase. There was a random variation in the temporal phase of the events of audio-visual synchronization. Appearance of the synchronized visual element occurred approximately 20 times for the location of sinusoidal and square-wave modulation conditions (760 trials were conducted for each of the participants). Procedure The participants were requested to maintain a fixation, which was determined by a centrally located fixation point. The participants were at a distance of 80 cm from the monitor of the computer. Each participant was required to provide a report, which identified at least one of the nineteen modulations of disk luminance that had a tone synchronize. A standard computer keyboard was used to type numbers to a dialogue box, which corresponded to the identified disk. Results After the experiment was conducted the results were tabulated in excel spreadsheet for data analysis. Analysis of Variance (ANOVA) for the results obtained was conducted with reference to the time of reaction. The design was a 2 × 4 repeated ANOVA measures, which had the ability of indicating whether the attained means had any similarities. Tukey’s HSD was used as a tool for making a comparison of the factors. The results illustrated that there was a significant interaction for the fixation (waveform × location) of F (3, 22) = 27.5, at P 0.05 Averages for the sine wave Table 2: Averages for the sine wave Location N S E W Average 0.1047 0.1155 0.1405 0.1276 STDEV 0.0622 0.0701 0.0633 0.0935 Figure 3: bar graph of the main effect of the sine waveform Discussion The results suggest that sine waveforms and square waveforms were quite different as illustrated in figures 2 and 3. The standard deviations for both sine and square waves are also different. The standard deviations obtained illustrates that sine wave has a smaller relationship with respect to location and proportion. From figure 2, it was evident that square wave is periodic and results in a sudden change of the amplitude. Figure 3 indicates that sine wave is periodic and has a gradual change in amplitude. For the square wave, the ANOVA yielded F (3, 22) = 43.83, p < 0.001, which was a clear indication that there was an improvement in the tone synchronization with respect to the target annulus in comparison to conditions when such a target never existed. On the other hand, when the events of audiovisual were at sine-wave modulation, such interaction of audiovisual could not be observed as depicted by the ANOVA results F (3, 22) = 1.35, p > 0.05. Moreover, the presence of the tone main effect was not reliable at F < 1. Search slopes on the conducted experiment leads to suggestions that the event of visual did not have the ability to attain the desired attention in an automatic fashion (Fujisaki et al., 2006). This could be true, however, classical studies that suggest that there is a visibility of the salient singleton up to the making of the response, but for the present case salient event (audiovisual event synchronization) was just present temporary. Therefore, missing of this event by the participants means that they had to wait until the next synchronization of the audiovisual event occurred (Yantis, & Jonides, 1984). This has a correlation to previous studies, which illustrate that attention in the synchronization of audiovisual event is captured, but the case does not happen for all trials. This is attributed to blinks and eye movements. Square-wave attained substantial search benefits, but the presentation of the audiovisual events never occurred simultaneously (Van de Burg et al., 2008). This sinusoidal condition could not be optimal. The stimulus effect for this experiment may be associated to the situation that sine-wave condition depicts a higher sensitivity to temporal synchrony in comparison to the condition of the square-wave. Further, sinusoidal modulation (as indicated in figure 1) led to generation of greater proportion of time and luminance correlations in comparison to the modulation of the square-wave (Van der Burg et al., 2009). This leads to making an argument that sinusoidal modulation has the potential to yield more of luminance temporal information when compared to the modulation of the square-wave. The main limitation of this experiment is that there was no control experiment, which could be used to determine the mean error rate, as well as individual harmonic conditions. This indicates that the results and analysis are reliant on just one experiment, which could have inherent errors due to internal human conditions of the participants. Moreover, the auditory and visual response rates of human beings are different. As such, it was difficult for this experiment to determine accurately the auditory and visual rates of the participants. In addition, the experiment could not determine the reliability of the 2 × 4 repeated ANOVA measures for the interactions since there was no seclusion of the harmonic conditions. Conclusion The results obtained from this experiment illustrate that temporal alignment of audiovisual leads to attainment of success in audio search if component signals changes are transient and synchronized. Further, synchronization of audiovisual events under sinusoidal led to attainment of no benefits for this research while modulations of audiovisual events at square-wave promoted attainment of benefits for visual search (Van der Bur et al., 2010). The findings compel the experimenter to make a proposition that transient signals needs synchronization for the case of avoid interactions of signals that are not related. References Fujisaki W, Koene A, Arnold D, Johnston A, & Nishida, S. (2006). “Visual search for a target changing in synchrony with an auditory signal.” Proceedings of the Royal Society B: Biological Sciences. 273: 865–874. Thomas, GJ. (1941). “Experimental study of the influence of vision on sound localization.” Journal of Experimental Psychology 28: 167–177. Van der Burg E, Olivers CNL, Bronkhorst AW, T & heeuwes, J. (2008). “Pip and pop: Non spatial auditory signals improve spatial visual search.” Journal of Experimental Psychology: Human Perception and Performance 34: 1053–1065. Van der Burg E, Olivers CNL, Bronkhorst AW, & Theeuwes, J. (2009). “Poke and pop: Tactile-visual synchrony increases visual saliency.” Neuroscience Letters 450: 60–64. Van der Burg, E, Cass, J, Olivers, C, Theeuwes, J, & Alais, D. (2010). “Efficient Visual Search from Synchronized Auditory Signals Requires Transient Audiovisual Events”. PLoS ONE, 5 (5). Yantis S, & Jonides, J. (1984). “Abrupt visual onsets and selective attention: Evidence from visual search.” Journal of Experimental Psychology: Human Perception and Performance 10: 601–621. Read More

Hypothesis 2: modulation of signals improves vision and leads to attainment of better performance. In review of the results obtained in this experiment, it is evident that sine-wave modulations have no ability to attain any benefits in visual search for audiovisual synchronization while the square-wave modulations attain benefits in visual search of synchronization of audiovisual events. This illustrates that square-wave and sine-wave benefits are attributed to synchronization of auditory stimulus and the transient luminance event, but not due to amplitude or discrete and continuous variation.

Method Participants This experiment included 23 participants where 19 were females while 4 were males. The participants enjoyed a course credit with reference to their participation in this research. Design The stimulus type, which was the independent variable for this experiment was either a square-wave modulation or a sine-wave modulation. The other independent variable was the target visual field location north, south, east, and west. The dependent variable for the experiment was the ability of the participants to accurately detect the target and their reaction time.

Reaction time was characterized of the time interval between onset of the display and attainment of the response for this target. Equipment The following apparatus were used in order to run this experiment: PC running E-Prime software, a dark room, standard computer keyboard, Sennheiser headphones, and computer monitor (Mitsubishi Diamond Pro of 1024 × 768 pixel of resolution with a running frequency of 100 Hz at refresh rate). Stimulus A fixation point was predetermined at the center of the screen.

Each trial comprised of nineteen luminance-modulating disks. These disks were equidistantly placed on an imaginary circle from the fixation at visual angle of 15 degrees. Each disk had its diameter subtending a 0.5 degrees visual angle. The disk had a luminance variation in the range between 0.1 at minimum to 165 cd/m2 at maximum. Periodic modulation was achieved for each disk at a modulation cycle of 1 second. Each trial comprised of two cycles of modulation. The modulation phases for the disks were different (the disks had different times of attaining their maximum and minimum luminance), but the rate of luminance for disk modulation was the same (1 cycle per second or 1 Hz).

Temporary adjacent disks had a phase difference of 50 ms. Individual disks had a maximum luminance at 0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850 & 900 ms. The temporal phases were randomly allocated for each trial at the 19 possible spatial locations. Either a square-wave or sinusoidal wave was attained as the modulation profile for temporal luminance for a given trial. Determination of this occurred randomly for the trials. Each trial indicated a 500 Hz tone, which had a closer resemblance to the visual elements modulation rate.

A single visual element was used to synchronize the tone of each phase. There was a random variation in the temporal phase of the events of audio-visual synchronization. Appearance of the synchronized visual element occurred approximately 20 times for the location of sinusoidal and square-wave modulation conditions (760 trials were conducted for each of the participants). Procedure The participants were requested to maintain a fixation, which was determined by a centrally located fixation point.

The participants were at a distance of 80 cm from the monitor of the computer. Each participant was required to provide a report, which identified at least one of the nineteen modulations of disk luminance that had a tone synchronize. A standard computer keyboard was used to type numbers to a dialogue box, which corresponded to the identified disk. Results After the experiment was conducted the results were tabulated in excel spreadsheet for data analysis. Analysis of Variance (ANOVA) for the results obtained was conducted with reference to the time of reaction.

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