Change in reaction times due to alcohol consumption.

AS BIOLOGY

THE EFFECTS OF ALCOHOL ON REACTION TIME

HYPOTHESIS

INTOXICATION will slow down your reaction time, as the amount of alcohol consumed increases, reaction time will increase. (Your body will take longer to respond)

BIOLOGICAL KNOWLEADE

REACTION TIME

The experiment tests how long it takes the brain to translate visual information (falling ruler) into your voluntary (or conscious) motor commands and actions (grasping finger movements) that lead to the ruler being caught. The shorter the time, the faster your reactions. That’s if you were paying attention in the first place! Indeed practice specifically affects the ‘associative centers’ in the brain, so that you can respond faster to what’s happening in your visual world. The flow of information along the ‘visual’ and ‘motor’ nerve pathways is relatively constant even with lots of practice.

ALCOHOL CONSUMTION

Alcohol is classified as a depressant because it slows down the central nervous system, causing a decrease in motor coordination, reaction time and intellectual performance. At high doses, the respiratory system slows down drastically and can cause a coma or death.

Alcohol can be taken up by any body surface but is most efficiently taken up as it is usually consumed; after drinking an alcoholic beverage. Alcohol is absorbed over almost the entire length of the digestive tract. Absorption from the mouth and oesophagus (canal between mouth and stomach) is minimal. Ethanol absorption from the stomach may vary between 10 and 30 %. The remainder of the ethanol is absorbed from the duodenum and small intestine. Overall, more than 90% of all alcohol consumed is absorbed, irrespective of the presence of food in the stomach. Uptake is slowed down in the presence of food and uptake is faster-- when alcohol concentrations are higher.

After uptake alcohol distributes over all body parts, specifically those parts that are highly perfused with blood, such as brain and liver. Therefore, these parts will reach high blood alcohol levels relatively quickly. Alcohol distributes through body water mainly. This means that men, who have on average more body water then women, generally achieve lower alcohol concentration. Men have more body water for two reasons: they are heavier and they have less body fat per kilogram of body weight. Consequently, the same quantity of alcohol per person usually results in a higher blood alcohol concentration in women as compared to men.

Alcohol is primarily broken down or metabolized in the liver through two steps mainly: firstly, it is broken down or oxidized to acetaldehyde by an enzyme called alcohol dehydrogenises. Acetaldehyde is very toxic and held responsible for most of the harmful effects of excessive alcohol consumption. Secondly, acetaldehyde is efficiently converted into acetate by an enzyme called acetaldehyde dehydrogenises. Acetate is a harmless compound, which is used for energy generation. The total amount of ethanol broken down per hour is estimated in the range of 0,1-0,3 gram per kilogram body weight per hour. This is usually translated into 6 – 9 gram ethanol per hour for a healthy subject. These fundamental processes are common to all human beings and sufficient to break down moderate quantities of alcohol. However, environmental factors (drinking habits) and genetic factors (activities of the enzymes involved) may affect the rate of alcohol metabolism.
Specific groups, like about 30-50% of Asians, have an inactive acetaldehyde dehydrogenises enzyme, which results in higher acetaldehyde levels in the blood upon alcohol consumption. These high acetaldehyde concentrations cause facial flushing, cardiac arrhythmia, headache and vomiting.
When more alcohol is drunk than the above mentioned enzymes can break down, other enzymes will start breaking down alcohol as well. The relative importance of these enzymes is therefore determined by the dose and the duration of alcohol consumption. The activity of the alternative enzymes contributes to toxicity and possibly carcinogenicity in alcoholics.

Only a small proportion of alcohol is excreted with urine, breath, sweat and tears, in other words: practically all alcohol is broken down. Generally speaking: 90-98% is broken down, 1-5% is excreted via the lungs by expiration, and 1-3% is excreted via the other routes, like urine (0.5- 2.0%) and sweat (up to 0.5%).

Alcohol depresses the functioning of the body's cells and organs, making them less efficient. Alcohol's effect on the brain is dangerous, as the brain is responsible for coordinating critical body functions such as the senses, perception, speech, and judgment. Socially, drinking is dangerous in that emotions are more freely expressed when one is intoxicated. This is because the part of the brain that allows us to control our actions and behavior is relaxed. There is a loss of self-restraint. This results in things such as slower reaction times.

In addition to the effects that alcohol has on your body from just one night of drinking, there are serious long-term effects for heavy drinkers. Due to the irritant action of alcohol, high consumption increases the risk of cancers of the mouth, tongues, and oesophagus. There is also the risk of liver diseases such as hepatitis, cirrhosis, and liver cancer. Heavy drinkers are also at risk for coronary heart disease, high blood pressure, and stroke. For those who drink only occasionally, the body is able to adjust to the depressant effects of alcohol. However, frequent alcohol consumption does not allow ...

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APPARATUS

5 Participants, (All in the age group of (18-19 and all female)
Meter Ruler (for first reaction time test)
Calculator (to work out reaction time)
Computer (for second reaction time test)
Alcohol (I will need 25 units of alcohol to carry out my experiment)
Mixer (coke) this will be 2 mixes with the alcohol.
Glasses (to drink the alcohol from)

PROCEDURES

Five participants (over the age of 18) will each do a series of reaction time tests. (One by one)
No participants will already have any alcohol in their system
I am going to of made sure that each participants have got an empty stomach because if some of them have ate before hand then this will absorb the alcohol quicker.
Firstly the ruler drop test
I will hold a meter ruler at the zero end, and I will ask my first participant to place a hand close to the ruler, between there finger and thumb at either side, but not actually touching it.
I will then let the ruler drop, with no warning and the participant must catch the ruler between their thumb and first finger.
Then I can work out how far the ruler has dropped before it was caught by counting how many cm it has fallen from the zero.
Each participant will do this test three times and then I will take an average of the three results. The experiment will then be repeated with each participant.
The second reaction time test, which I am going to be using, is on a computer screen.
On the screen there will be a red light and a green light and the red light will be lit up.
The participant has to concentrate on the red light and as soon as it switches to the green light they have to press a button immediately.
This will then give an automatic reading of how quick their response time is.
Again this test will be repeated three times and an average will be taken. And this will be repeated with each participant.
I will then give each participant 1 unit of alcohol to drink and do the same tests exactly the same as I have just described.
I will repeat this after 2units, 3units, and 4 units and then finally 5 units of alcohol have been consumed each time being mixed with the same amount of coke (mixer). I will use 100 ml of coke each time.
I am going to do my experiment over a 5 day period. On day 1 I am going to test the response time of each participant after 0 units of alcohol and then after 1 unit of alcohol.
Second day I will test after 2 units of alcohol
Third day 3 units, etc.
I am also going to measure each participant on after each unit of alcohol after 0 minutes, 20 minutes, 40 minutes, etc. to check if over time the reaction time increases or decreases.

BELOW IS A TABLE OF HOW I AM GOING TO RECORD MY RESULTS.

VARIABLES

Alcohol amounts – This the variable that I am going to chance. It will vary from 0 units of alcohol to 5 units of alcohol.

Mixer amounts – (I will the same vol of coke with each unit of alcohol consumed)

Keep the same 5 participants throughout the whole experiment.

Participants with empty stomachs- (each participant has to have an empty stomach so the alcohol won’t get absorbed quicker)

Participants have to have had no alcohol in system before hand. – (Making sure by doing my participants know the riles and procedures before the experiment)

Gender of participants will stay the same throuout the experiment.

Time- Keep the same time distance between intoxication and doing the response time tests. (0 minutes, 20 minutes)

Same equipment – same ruler for the ruler drop test with each participant and after each unit of alcohol has been consumed.

Environment - the experiment will take place in the same room; I will use the same conditions for all the participants. I will not alter the lighting or the temperature of the room. As this could effect someone’s concentration.

Age- I will make sure that all the participants are all of the same age. I will have to make sure that all the participants are over the age of 18, because it is illegal to buy alcohol under the age of 18.

Time of day- this will be kept constant by just doing the test in the morning. The accepted best time to do this experiment is in the morning due to the stresses of the day haven’t taken place yet and you have just rested from a nights sleep so your reaction times will most probably be better.

Briefing- Before the participant takes part in my experiment I am going to give those detailed instructions of what I am doing and why I am doing it.

I will do this experiment when I am in control so that I no that no participants will be driving.

ANALYSIS

Changes to original method

I decided that I wanted more reliable results so I decided to do 5 repeats on each participant rather then 3 so that I no the final results will be more accurate. I also decided to just do the one reaction time test which was the ruler drop one because I found my second reaction time test wasn’t very accurate. And do to lack of time I only repeated my experiment before intoxication and then 30 minutes after, rather then every 20 minutes. I also discovered that my results table wasn’t going to work o I have also changed the design of that.

Results

Below are my results for the ruler drop test, off 5 different participants being tested after consuming between 0-5 unit of alcohol at 0 minutes and 30 minutes after consumption?

The table below is a table of all my results but averaged so that you can see the comparisons of each participant a little easier. I have also averaged but all the participants’ scores together for each unit of alcohol consumed, which is the results I am going to be making into a graph.

Trends

My results followed a general pattern, which is that the higher intake of alcohol the worse reaction time and also the longer the alcohol has had to be absorbed by your body the worse reaction time is. As I discovered this from measuring reaction time after 0 minutes and 30 minutes. As you can see from the graphs each participant has slightly different results due to personal differences. but they all still follow the same general pattern, which is that each participants reaction time was below 1.0m/s after having no units of alcohol and it gradually increases after intoxication, which I expected, but I also found that when the participants reaction time was measured after having 4 units and 5 units, There was a greater increase in reaction time. For example on graph 1 the line measuring reaction time after 0 minutes you can see that between 0-3 units the reaction time has increase by 0.77ms. Whereas between 3-5 the reaction time has increased by 1.31ms. Proving that the more you drink the less aware you are, and the slower your brain is at translating visual information. (The ruler dropping)

Anomalies

In this experiment I was expecting there to be quite a lot of anomalies. Due to human error. The main reason why there was a variation in results is that each participant has a different sense of reaction time to start with soom may have very poor reaction time, where as others maybe have generally very good reaction time. This is why I decided to do so many repeats. I have indicated on my tables where I got some dramatic anomalies. Each anomaly, 2.53, 2.894, 3.481, 3.481.They seemed too high to compare All increased the averages making the trend less obvious. But I think that the reason of each one of these was due to lack of concentration by the participants or getting distracted as the ruler is about to be dropped. I decided to still include these results into my experiment because although it lack of concentration doesn’t have anything to do with reaction in could still be a result of intoxication. I.e. easier to distract. The other anomie I found was that the results for participant 3 where a lot lower then the rest. The participant’s reaction time hadn’t increased as rapidly as each other participants. Compared to the other

Results for that participant which were, 2.83, 2.97, 2.8, and 2.87. I think the reasoning for this is because the participant has a better general reaction time then the other participants or their have a higher consumption of alcohol in day to day life, and so resulting in 5 units of alcohol not have such a great effect on their bodily actions and systems.

Explanation

The result of intoxication on the human body’s reaction time is that it increases your reaction time. And the more alcohol taken in by the body the more your reaction time will increase, due to the brain not being able to function as quickly as it would before intoxication.

And in addition the longer the body has to absorb the alcohol the slower your reaction will be, due to the body having longer to process the alcohol and for full absorption to take place. Because all your reaction time is, is the interval between the presentation of a signal and the observer’s response to that signal. And they are many factors which could effect it, alcohol just being one of them number of factors. As I have found out by my experiment alcohol varies how it works on everyone differently, because some of my participant’s reaction time after 5 units of alcohol was a lot slower then others. For example participant 3’s reaction time was a lot better then participant 5’s. Other factors which alcohol does to people are loss of coordination, balance, and motor skills. Heavy drinkers stagger when they walk, have slurred speech, fall over things, and cannot control when they urinate. All this plus slower reaction times are due to the breakdown of the nervous system. Because it slows down the passing of messages and because the messages are travelling slower this is why our reaction time is slowing down. My conclusion can be backed up by my Biological knowledge in my plan.

Evaluation

Variability

From previous knowledge I expected that the greater the intoxication the slower the reaction time would be. But I wasn’t sure after what period of time your reaction time would be worse. My results are pretty consistent, apart from the anomalous which I have stated in the analysis, Results such as anomaly, 2.53, 2.894, 3.481, 3.481 were all to high for me to compare o I clearly stated them in on the tables and I think the main reasons for these results were the variation in people I used, and also lack of concentration, all due to personally differences, which is what I was expected anyway. I decided not to remove my anomalous results out of my coursework I think I got a move true measure by keeping them in and my results still followed a pattern. And they did relate to what I was expecting.

Reliability

I am generally happy with my results I have achieved, I do think that my results do show the true effect of alcohol on a person’s reaction time as it confirms the background knowledge I already had. And my conclusion backs up my hypothesis. In my conclusion I have related my results into every day life, and also what other effects alcohol could have on the human body. I feel that the experiment was a fair test and so the results were precise. But I do think that they could have been a little more accurate if I had of had more time to do some extra repeats so that I could of deleted my anomalies. And also if there was a more precise test that you could do to asses’ reaction time, as I think you can make quite a lot of human errors in a ruler drop test. Another problem with the design of my experiment was that I hadn’t stated at all in my procedures anything to do with how fast each drink had to be consumed because this could also be a reason as to why different participants got different readings. Because it has been said that if you drink a drink fast you get drunk quicker. So I would defiantly take this into account if I ever decided to take this experiment further.

Criticism and Limitations

My experiment could have been planned a lot better. If I had stuck to my original plan I think my results could have been a lot more accurate and be more reliable. As it had stated I would be doing two different reaction time tests. This means I would have got a wider variety of results. And also I could have got a lot more readings if I had off taken a recording after every 20 minutes like I said I would of. But due to lack of time I couldn’t do this. Other problems I encountered while taking out this experiment was to measure out the units of alcohol correctly in comparison to the mixer, due to the equipment I was using, so this means my measurements could have been slightly wrong resulting in some participants getting slightly more or less alcohol then another, which could defiantly of had an influence on the results. Although I don’t think this could really account for any of the anomalies though because the anomalies were just one of readings and they weren’t consistent to one person as they would have been if they hadn’t of consumed as much alcohol as the other participants. Other then this I think that the experiment was conducted well, I followed my procedures as far as possible and I was happy with my results.

Suggestions

To expand on my Conclusions I could have done various different things, such as, more repeats, do a variety of different reaction time tests, I should of took more time, and planned my experiment better And also as I stated earlier took into account how long each participant took to drink each drink. I was aiming to do all these things in my investigation, if I had of done this my conclusion would be more detailed and defiantly more reliable as I would have got rid of the anomalies and be able to expand on my explanation.

If I was to extend my study, to get a wider range of results I think that I would like to investigate what other effects alcohol has on the body. Such as does it affect heart rate, etc. or the other root I could take is to investigate what other things effect someone’s reaction time, such as drugs and caffeine. Another interesting study which I would like to investigate further is to do an investigation similar to this but give each participant the same amount of alcohol but then change it so one participant hasn’t eaten anything and then that each of my other participants have eaten the same thing but at different times throughout the day, and see if this has any effect on how the body absorbs the alcohol after food consumption. Then this could be modified by giving participants different types of food. For example bread. Because this is mend to absorb alcohol quicker.

Danielle Robinson Page 5/2/2007