THE INFLUENCE OF ENERGY DRINKS ON RACTIVITY TO MULTIPLE STIMULY-A PILOT STUDY DAISY MONALISA GRANSCA a, MIHAI ANITEI b a,b University of Bucharest, Department of Psychology Abstract The experimental study represents a pilot study focused on highlighting the influence of energy drinks consumption (1000mg taurine) on reactivity to multiple stimuli. The stimuli are visual colures and auditory signals. Method: The participants are 60 undergraduate students at psychology, Faculty of Psychology and Educational Sciences, University of Bucharest, age between 19 and 22 years old (M=20.48; 0.76), rural and urban area. Instruments and materials: DT test (Vienna Tests System, 2012) and energy drinks with 1000mg taurine for each portion. Dependent variables are: correct, incorrect and omitted. Results: Applying T student statistical test for mean differences the statistical hypotheses were confirmed (p<0.05). Furthermore, the experimental group with 1000 mg taurine consume obtained a number of correct, incorrect and omitted statistically significant lower than the control group. Conclusions: Consuming energy drinks with taurine may offer a powerful sensation of energy on one side, but on the other side may reduce the cognitive capacity of the brain, attention to the visual and auditory stimuli measured by the number of correct to visual and auditory stimuli. Cuvinte cheie: stimuli vizuali, stimuli auditivi, băuturi energizante, număr de reacţii corecte, număr de reacţii incorecte. Keywords: visual stimuli, auditory stimuli, energy drinks, number of correct, number of incorrect. * Corresponding author: Mihai Aniţei. Email: mihai.anitei@unibuc.ro 32
1. INTRODUCTION One of the first studies conducted by Serfling Hetzel & Ykema (2008), University of Winona State, proposed to verify the affirmations of an energy drink producer has made to promote his product. They included 38 subjects to their study and have tested their cognitive processes by applying the Stroop Effects Test. The resulting scores have shown that the hypothesis could not be confirmed, namely that the cognitive processes were not perfected following consuming energy drinks which played the role of independent variable. Warburton, Bersellini & Sweeney, (2001) were interested in studying the energy drink consume containing caffeine and taurin on mood, memory and information processing. Another interesting study has also shown the variety of physiological and psychological effects which were attributed to energy drinks and their ingredients. În this way, Chraif & Aniţei (2011), have conducted a study on the benefit of the Faculty of Psychology and Educational Sciences in the attempt to demonstrate that consuming a certain doses of caffeine and energy drink might influence the reaction time related to peripheral visual stimuli and the number of correct answers and errors of visual stimuli of the central field. The obtained results have shown that consuming quantity of 165mg of caffeine rises the reaction speed of the visual stimuli, the statistic reaction time lowers (p<0.05), the correct speed and distance estimation of the visual stimuli showing significant statistic lower scores (p<0.05) both for periphery visual stimuli and central stimuli. Moreover, consuming energy drinks (2000 mg of taurine) has a reducing effect on the correct evaluation of moving visual stimuli in the central field (p<0.05). The conclusion of the study emphases the idea that consuming caffeine and energy drinks reduces the reaction time and increases the number of incorrect answers related to estimating the movement speed from the central and periphery field. Furthermore, Aniţei, Schuhfried, & Chraif, (2011) highlighted the effects of energy drinks consumption on reaction time and cognitive processes. The previous research conducted at the experimental psychology laboratory of the Faculty of Psychology and Educational Sciences of the University of Bucharest have focused on the motor reactivity and reaction speed (Aniţei, 2007; Chraif, 2013) after the caffeine drinking, the influence of caffeine drinking over estimating speed and distance, the influence of caffeine consume on the Stroop test results. Another study approaches the frequency with which nowadays, in the university campus, students of all educational domains use energy drinks as an ingredient for their alcoholic drinks and the time of day they choose to consume them. 33
The reason of consuming energy drinks in the morning is that they give the impression that the body will function during the rest of the day on full capacity in order to obtain high performances. The majority of people who consume energy drinks for this purpose are most likely to experience the placebo effect. Another study has briefly explained the results that demonstrate that excessively consuming energy drinks may lead to a low to moderate euphoria mostly caused by stimulating properties of caffeine and may also induce agitation, anxiety, irritability and insomnia (Alford, Cox & Wescott, 2001). 2. OBJECTIVE AND HYPOTHESES 2.1. OBJECTIVE The objective of the study is focused on demonstrating the influence of energy drinks that contain a higher level of caffeine and taurine on stress tolerance, attention and reaction speed and also on the perception of visual and auditive stimuli 2.2. HYPOTHESES The consume of 1000mg taurine from energy drink influences statistically significant the number of correct to stimuli at the experimental group comparing with the control group. The consume of 1000mg taurine from energy drink influences statistically significant the number of correct to stimuli at the experimental group comparing with the control group. The consume of 1000mg taurine from energy drink influences statistically significant the number of correct to stimuli at the experimental group comparing with the control group. 3. METHOD 3.1. PARTICIPANTS/SUBJECTS In order to verify the research hypothesis a number of 60 students have been selected from the Faculty of Psychology and Educational Sciences, 15 of them being male and 45 of them female, aged between 20 and 27 years old, coming both from rural and urban environments. 34
The participants have been divided into 2 groups. The first group, namely the control group was composed of 30 students and the second group composed of the same number of students, the experimental group which received the energy drink treatment. N-60 participants, male and female, randomly selected from the population of undergraduate students, first grade. 30 participants Control Group 30 participants, Experimental Group with energy drink consume, 1000 mg taurine Figure 1. The groups design used to test the hypotheses 3.2. INSTRUMENTS Determination test (Vienna Tests System, 2012) is a test that evaluates to multiple stimuli consisting of simultaneously presenting colored stimuli and acoustic signals. The subject responds by pressing buttons placed next to the response panel and by using the foot pedals. The objective of the Determination test is to measure the reactive tolerance to stress and the reaction speed. Using this test involves the following cognitive acquisitions: - discriminating the colors and sounds; - the ability to remember relevant characteristics of the stimuli features, the response buttons and the indicated rules and patterns; - selecting the relevant response according to the rules indicated to the instructions or taught during the test; - motor skills which represent operating buttons and foot pedals. 35
Figure 2. Item stimuli from the testing procedure The difficulty of Determination Test comes from the need on maintaining constant, fast and various responses to a rapid switch of stimuli. The difficulty level thus depends mostly on two variables: the speed of change in stimuli and the number of stimuli and responses that the subject is supposed to move. Presenting the stimuli might take place in three different ways, depending on the application mode and the time given: Reaction mode (the time settles in the presentation for each stimuli). Each stimuli is displayed in a settled period of time; the next stimuli is shown, independently to the presence or absence of the reaction. The exact number of correct answers depends on the length on presentation time. Because the presentation time of each version of the test is fixed, we may say that the test measures primarily the ability of the subject to adapt the reaction speed so he misses as few stimuli as possible while, at the same time, he keeps the cognitive accuracy; the action mode unlimited time of display of stimuli, the settled duration of the test. The following stimulus shows up when a correct response was given by the subject, the speed of stimuli display is determined by the subject; the adaptive mode (automatic variation of display time); In the adaptive mode the speed of stimuli display depends on the work rhythm of the subject. The duration of each stimulus is calculated as a mean of the last eight scores of reaction time. If the response to a stimulus was not correct, the reaction time will be doubled in order to calculate the duration of the following stimuli. The form of presentation assures that the subject is constantly concerned about the limit of his abilities and that the tolerance to stress reaction is thus fairly evaluated. The speed of stimuli presentation is continuously adjusted to the work speed of the subject. 36
In order to conduct this research the S1 version of the Determination test was used, which is also named the adaptive method, and has duration of 8 minutes. 3.3. PROCEDURE The participants completed the consent certificate form and started the test administration procedure. The language was Romanian. Figure 3 shows a sequence of the applying procedure of the DT test version S1. Figure 3. Item stimuli from the test administration procedure During the actual testing phase, the respondent is presented colors and acoustic signals as stimuli. The subject reacts by pressing the allied buttons on the response panel. The stimuli are presented in the adaptive mode, while the display speed is adjusted to the performance level of the subject. The subject is asked to use the headphones in the equipment to make sure that the exclusion of sounds might distract his attention. 3.4. EXPERIMENTAL DESIGN The independent variable is represented by the quantity of energy drink containing 1000mg of taurine, glucoronolactona, vitamine B complex and sugar. In the case of the DT test the dependent variables are represented by: the number of correct, the number of incorrect, the number of missed ; the number of stimuli which the subject has been exposed to and the number of his. 37
Control group 30 participants No variable independent Data collection as responses to DT test form S1 control group Experimental group 30 participants Consume of 1000mg of taurine as energy drink Data collection as responses to DT test form S1 Experimental group Figue 4. Experimenta design for hypotheses testing (Chraif, 2013) Figure 4 shows the procedure of hypothesis testing for the three variables measured using the DT test: the number of correct, the number of incorrect, the number of omitted. The taurine consumed in 1000mg is applied only on the experimental group. 4. RESULTS In order to determine thenature of data distribution the Kolmogorov-Smirnov test was applied. If the data is normally distributed than the p value is higher than the 0.05 limit. Table 1. One-Sample Kolmogorov-Smirnov Test for the control group Corecct Incorect Number of Number of Omitted stimuli N 30 30 30 30 30 Normal Mean 440.40 34.23 50.97 504.77 474.63 Parameters a,b Std. Deviation 88.697 17.242 21.147 88.737 91.594 Most Extreme Differences Absolute.108.109.109.167.127 Positive.063.109.079.108.065 Negative -.108 -.064 -.109 -.167 -.127 Kolmogorov-Smirnov Z.590.599.598.916.698 Asymp. Sig. (2-tailed).877.866.867.371.714 38
In table 1 we notice that Kolmogorov-Smirnov test for verifying the normal distribution of data applied for each dependent variable, confirm the normality of the distribution for each variable (p>0.05). Table 2. One-Sample Kolmogorov-Smirnov Test for the experimental group with energy drink Number Corecct Incorect Number of Omitted of stimuli N 30 30 30 30 30 Normal Parameters a,b Most Extreme Differences Mean 274.20 21.90 18.00 299.27 296.10 Std. Deviation 34.013 15.895 8.179 34.009 38.186 Absolute.149.164.104.135.117 Positive.149.164.104.135.117 Negative -.094 -.125 -.090 -.085 -.064 Kolmogorov-Smirnov Z.817.896.569.737.643 Asymp. Sig. (2-tailed).517.398.903.648.803 In table 2 we notice there is a normal distrubution of the data (p<0.05) for the DT test to applying the Kolgomorov-Smirnov test, thus applying the student T test on independent groups. Table 3. Descriptive Statistics Correct Incorrect Omitted Number of stimuli Number of Group type N Mean Std. Deviation Std. Error Mean Control 30 440.40 88.697 16.194 Experimental 30 274.20 34.013 6.210 Control 30 34.23 17.242 3.148 Experimental 30 21.90 15.895 2.902 Control 30 50.97 21.147 3.861 Experimental 30 18.00 8.179 1.493 Control 30 504.77 88.737 16.201 Experimental 30 299.27 34.009 6.209 Control 30 474.63 91.594 16.723 Experimental 30 296.10 38.186 6.972 39
In tablr 3 we notice the Mean, Standard deviation and error of the variable for the control group and the experimental group using energy drinks as an influence on all variables of the applied test. Table 4. Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means Mean Std. Error 95% Confidence Interval of the Difference F Sig. t df P value Difference Difference Lower Upper Corecte 11.691.001 9.583 58.000 166.20 17.34 131.48 200.91 9.583 37.348.000 166.20 17.34 131.07 201.33 Incorecte 1.852.179 2.881 58.006 12.33 4.28 3.76 20.90 2.881 57.620.006 12.33 4.28 3.76 20.90 Omise 22.480.000 7.964 58.000 32.96 4.14 24.68 41.25 7.964 37.486.000 32.96 4.14 24.58 41.35 Nr stimuli 8.521.005 11.844 58.000 205.50 17.35 170.77 240.23 11.844 37.340.000 205.50 17.35 170.35 240.64 Nr reactii 8.804.004 9.854 58.000 178.53 18.11 142.26 214.80 9.854 38.785.000 178.53 18.11 141.88 215.18 Table 4 shows the values of the T test and the limit of the statistical significance to testing hypothesis of differences between means. The results confirm the first hypothesis differentiating the means between the two groups: experimental and control. Hence, there is a significantly statistic difference regarding the variables such as correct between the experimental group which consumed energy drinks and the control group. Thus for the correct variable t= 9.583; p < 0,001) the mean energy drink group is significantly statistical lower than the control group mean (440.40>274.20). Thus the statistical hypothesis regarding the influence of consuming energy drinks on correct to visual and acoustic stimuli is confirmed. Therefore the experimental group which consumed an energy drink containing 1000mg of taurine has led to reducing the number of correct to visual and acoustic stimuli. 40
Figure 5. Histogram of the correct variable for the two groups: control and experimental In figure 5 we may analyze the histogram chart for the number of correct dependent variable for each separated group. For the incorrect variables there is also a significant difference between the control and experimental group. Thus the mean of the control group is higher than the one in the experimental group (34.23>21.90). The statistical hypothesis The consume of 1000mg taurine from energy drink influences statistically significant the number of correct to stimuli at the experimental group comparing with the control group is confirmed (t= 2.881; p=0.006<0.01). 41
Figure 6. Histogram of the incorrect variable for bothe groups: control and experimental In figure 6 we can analyze the histogram chart for the number of incorrect dependent variable for each separated group. For the omitted variables there is also a significant difference in the raw data between the control group and the experimental group. Thus the mean of the control group is higher than the one registered for the experimental group (50.97>18.00). The statistical hypothesis The consume of 1000mg taurine from energy drink influences statistically significant the number of correct to stimuli at the experimental group comparing with the control group is confirmed (t= 7.964; p<0.0001). 42
Figure 7. Histogram for the omitted variable for both groups: control and experimental In figure 7 we may analyze the histogram chart for the number of omitted dependent variable for each separated group. 5. CONCLUSIONS The objective of this pilot experimental study was to verify the possible influence of consuming energy drinks containing 1000mg of taurine on the number of correct, incorrect and omitted of the young students in the competence of the experimental group. After applying the student T test the statistical hypothesis have been confirmed (p<0.05). In addition, the experimental group which consumed energy drinks containing taurine has lead to a reduced number of correct, incorrect and omitted to visual and auditory stimuli. Hence, the results highlight that the number of correct, incorrect and omitted decreased for the experimental group comparing with the control group statistically significant (p<0.05). In this way we can underline that the consume of energy drink with 1000 mg taurine reduce the capacity of multiple stimuli reaction in the way of reducing attention to the visual and acoustic stimuli an also the decision capacity in choosing the correct stimuli to response. Received at: 21.09. 2013, Accepted for publication on: 05.10.2013 43
REFERENCES Alford, C., Cox, H., Wescott, R. (2001). The effects of red bull energy drink on human performance and mood. Amino Acids, 21 (2), 139 50. doi:10.1007/s007260170021. PMID 11665810. Aniței, M.(2007). Psihologie experimentală [Experimental psychology], Editura Polirom, Iaşi. Aniţei, M. (2010). Fundamentele Psihologiei [Handbook of psychology], Editura Universitară, Bucureşti. Aniţei, M., Schuhfried, G. & Chraif, M. (2011). The influence of energy drinks and caffeine on time reaction and cognitive processes in Demet Erol Öngen, Çiğdem Hürsen, Melahat Halat and Hayat Boz (Eds.) Elsevier, Science Journal (ISSN: 1877-0428), Procedia - Social and Behavioral Sciences Elsevier, 30, 2011, 662-670. Chraif, M. & Aniţei, M. (2011). The influence of energy drinks and caffeine on peripheral perception and estimation of speed and distance for the young Romanian students, in Chen, Dan (Edt) International Proceedings of Economics Development & Research, 23, 2011, 104-109. Chraif, M. (2013). Psihologie experimentală, suport de curs [Experimental psychology, handbook], Editura Universitară, Bucureşti. Serfling, A., Hetzel, B. & Ykema, L. (2008). Party Like a Rockstar: The Effect of Energy Drinks on Cognitive Ability. Psychology Student Journal, Winona State University, Retrieved June, 27, 2013, http://course1.winona.edu/cfried/journal/2008.html. Warburton, D.M., Bersellini, E., & Sweeney, E. (2001). An evaluation of a caffeinated taurin drink on mood, memory and information processing in healthy volunteers without caffeine abstinence. Psychopharmacology, 158, 322-328. Vienna Tests System (2012) DT test software REZUMAT Experimentul pilot de faţă este direcţionat spre a demonstra influenţa consumului băuturilor energizante cu 1000mg taurină asupra percepţiei stimulilor vizuali şi auditivi, mai precis asupra reacţiilor la stimuli vizuali şi auditivi.metoda: Participanţii sunt un grup de 60 de studenţi la psihologie, Facultatea de Psihologie şi Ştiinţele Educaţiei, Universitatea din Bucureşti. Vârsta subiecţilor este cuprinsă între 19 şi 22 de ani (M=20.48; 0.76), din mediul rural şi urban. Instrumente şi materiale: testul DT forma S1 (Vienna Tests System, 2012) şi cutii cu băuturi energizante fiecare cu 1000mg taurină. Rezultate: În urma aplicării testului T student s-au confirmat ipotezele statistice (p<0.05). Mai mult decât atât, grupul experimental care a consumat băutură energizantă cu 1000mg taurină a dus la reducerea numărului de reacţii corecte, incorecte şi omise la stimulii vizuali şi auditivi. Concluzii: Consumul de băuturi energizante poate oferi senzaţia de energie, rezistenţă fizică dar pe de altă parte reduce capaciatea de concentrare ceea ce reiese din numărul de reacţii corecte reduce pentru grupul experimental. 44