The effects of caffeine on reaction time

So, instead of slowing down the cell activity, it speeds up.

Caffeine effects part of the nervous system that controls respiration so that more oxygen is pumped through the lungs.

Caffeine also causes the brain blood vessels to constrict because it blocks adenosine ability to dilate them. This causes you to have an increased neuron firing in the brain. The pituitary gland sees all of the activity and as some sort of emergency occuring so it causes the adrenal glands to produce adrenaline.

Adrenaline causes the breathing rate to increase, breaks down glycogen to glucose in the liver to provide energy for the metabolic processes, blood flow to the stomach slows and muscles tighten up ready for action.

This explains why after consuming caffeine the hands get cold , heart beat increases and gives an excited feeling.

Caffeine increases dopamine levels in the same way that the amphetamines do-heroine, cocoaine manipulate dopamine levels by slowing down the rate of dopamine uptake. However the effect of caffeine is much lower than that of heroine’s but the mechanism is the same.

Dopamine is a neuron transmitter that activates the pleasure center in the thalamusof the forebrain.

It also stimulates reward pathways.

Caffeine is good in the short term, it gives the feeling of alertness and activeness. But the problem is in the long term.

Once the adrenaline wears off, most people face depression and fatigue, to overs ome that one must consume more caffeine. When comsumed too much it might cause confusion, headaches, irritability and an increase in the pulse rate. Caffeine tolerance however varies from person to person due to factos such as stress, behaviour, age, weight.

Sleep is the most effected by caffeine consumption. Adenosine reception is important to deep sleep. The half-life of caffeine in the human body is 6 hours so if 200 mg of caffeine is consumed at 2pm, by 8pm 100 mg of it will still be present. A person will sleep but the body will not benefit a deep sleep causing one to feel tired and worn out even after a long sleep. This deficit adds up till the next day and so on.

Variables:

My independent variable is the reaction time taken for the students to do the maths problems. This is a continuous variable.

My dependent variables are qualitative variables: age group and emotional state.

I took the age group 15-18. I took 5 people of each group so 20 individuals in all.

I took care to test the students at a time when they haven’t been doing any exercise, sports or going through any stress.

Outline method:

I will make two maths test papers and give it to the students when they have no caffeine consumed and after caffeine consumption.

I will then record the reaction time, no. of correct, wrong, and not attempted answers.

Caffeine source:

There are a variety of food products that I can use as a caffeine source.

From the products available Red Bull the energy drink has the most concentration of caffeine but it has other substances like taurine which effect the raction time and the bodies activities. Chocolate is a very easy product to find and consume but the concentration of caffeine is very less, same goes for beverated drinks. So between the tea and coffee available to me I choose Nescafe Instant Coffee because the concentration of caffeine is higher and it is more favoured by the volunteering people.

 

Replicates:   

I will carry out my investigation with 20 students os 4 ages, 5 of each age group.

Control:

I made sure the individuals didn’t ingest any source of caffeine in their diet for at least a day(coffee, tea, chocolate, fizzy drinks).

When testing the students I will be giving all the students the same maths test paper.

Safety procedure:

There are no harmful chemicals that I will be using or any sharp instruments so there are no safety problems.

However while dealing with hot coffee I will take care not to spill it on myself or the students.

I will use clean and disposable cups and spoons for each student.

Ethics and law:

Since I  carried out my investigation on the school students I was careful in choosing them. My experiment doesn’t harm them physically or mentally but I had to be careful like the people will all be fit and healthy and so not have any medical problems like asthma, any allergic reactions that would put their health at risk.

I carried out the experiment with the permission and supervision of a teacher.

Equipment required:

1 bottle Nescafe Instant coffee

sugar

disposable glasses

disposable spoons

stopwatch

Method:

I did the test for each student separately. Before giving the students the test I made them not do any kindof work, just sit down in their chair and relax for 5 minutes so that they wont get tensed abd stressed.

First I did a test for all the students when they had consumed no caffeine. I gave them the test and timed each individual separately using a stopwatch. I made sure the stopwatch was set to zero before I started timing.

For test 2 I made sure that they didn’t have any caffeine taken for at least a day. I made black coffee for each individual(no milk). I waited 10 minutes and then gave them the test. I timed them again as done before using a stopwatch.

When the students were doing the test I made sure that they were not disturbed or distracted by anything. They were not allowed to use calculators because this would be wrong for investigating the reaction time.

(The tests 1 and 2 are given in the appendix.)

Results and analysis:

Table 1 shows the results for Test 1 without ingesting caffeine.

     

Table 2 shows the results for test 2 with ingesting caffeine.

Analysis:

Table 3 shows the reaction times 1, 2 and their difference:

Anomalous results:

There are some anomalous results where the difference in reaction time is very less as in person 2-23seconds, and person 6-11seconds.

When looking at the marking of both the tests. It can be seen that there are 2 anomalous result, where the marks were less aafter consuming coffee-person 19 and 20. but their reaction time is much lesser with difference of 215 and 119 seconds.

Overall while looking at the tables it is seen that ther is a difference in the reaction times. It is almost halved which does show some effect of caffeine on the reaction time. To further test the reliability and accuracy I carried out a statistical test: Z test for matched samples.

Statistics:

I chose this test because my samples are matched(paired), my data is interval and my values are large in number.

In my invetigation-the effect of caffeine on reaction time was involving recording the reaction times of 20 people given maths problems, both before and after ingesting caffeine.

The table shows the reaction time of the 20 people before and after ingesting caffeine and the difference in reaction time.

Calculations:

Difference in reaction time= x

Average= y

Mean difference= d

Standard deviation= s

The Z test value=

Z = d√n

        s

                       

Z = 126.65 X √20

           56.73

    = 9.98

        10

   test value  =2

For a Z test, halve the significance level and substract the result from 100%= Probability

Significance level: 9.98 = 5

                              2

Probability: 100-5 =95

                             = 0.95%

 From the critical value table, the Z critical value is between 1.644853 which is less than the Z test value 9.98 so I reject my null hypothesis.

Final conclusion:

I now come to my final conclusion that caffeine does have an effect on the reaction time. It decreases it therfore making the student slove the problem faster. Caffeine being a stimulant gives an ‘alert’ and ‘fresh’ feeling which makes the student mentally active and also makes them solve the mathematical problems correctly.

Evaluation:

Using the tables, some effect of caffeine on the reaction time is seen. This is further proved by the statistical Z test performed. So I say that my results were reliable and that caffeine does have an effect on reaction time of an idividual.

Explanation of Charts:

From the test 1 chart, it is seen that the range of the reaction time is between 300-550 with some anomalous results below 300.

From the rest 2 chart, it is seen that the range for reaction time is between 200-400 with some anomalous results above 400.

While looking at these results, it has to be kept in mind that the mental ability and mathematical skills vary greatly from person to person.

Experimental Limitations:

If I was to repeat the investigation again I would do it with individuals of a wider age group including 20,40,60 year old individuals also.

I would repeat the investigation with another and a higher concentration of caffeine.

Bibliography:

Appendix:

Maths Test Paper 1

1. 256 + 375
2. 142 X 16
3. 1501 +621
4. 634 – 155
5. 68901 – 48112
6. 156 X 21
7. 810 – 210
8. 610 X 31
9. 561 / 3
10. 890 + 615
11. 728/2
12. 555/15
13. 134 X 212
14. 103 X 42
15. 25 – 10

Maths Test Paper 2

1. 266 + 782
2. 1610 – 210
3. 43 X 33
4. 630 – 153
5. 704 + 990
6. 3907 + 2630
7. 1547 X 57
8. 102 X 2
9. 8699 +213
10. 300/ 20
11. 1850 +1670
12. 182 + 163 + 21
13. 1094 – 123
14. 1567 – 248
15. 160 X 12