Psychology homework question..?

Question

My teacher gave us homework that says "Idenitfy the mistakes" at the top and then it says...

Lets say that I am interested in the effects of caffeine on memory. In order to test the effects of caffeine, I divide the class in half. All the students on the right are given five cups of coffee to drink, and one hour later they are given a test of memory. The students on the left are dismissed. After the first group has been tested, the second group returns and is given the same memory test as the first group. The average scores are compared, and they show that the first group remembered more than the second group.


So...what does he want us to do? lol

What mistakes . . it sounds all right to me? lol

oh and he said there are 6 mistakes

Answer 1

The biggest problems are :
(a) group assignment,
(b) equality of conditions, and
(c) controls

1. One group is "dismissed." You don't know what the individuals in that group are doing when they are not in the room. Some might be taking advantage of the break to have a Coke. Maybe some left. . . who knows. . . but the point is, you don't have control over their behavior for that period of time.

2. Participants in the non-caffeinated group were in the room when the other group got their coffee. Maybe they got ticked off and wanted some coffee, too, and this impacted their performance. The point is, you don't know what the impact on performance was by having them view what was happening to the "experimental" group.

3. Participants were not randomly assigned to groups. Dividing in half is quasi-random, and while one might assume that individual differences are equally distributed, but you can't be sure. Maybe people who sit on the right side of the room are more motivated to perform well on tasks..

4. The second group is taking the test under different conditions than the 1st. . . the other people are present (perhaps making noiser conditions and impacting performance).

5. In addition to seeing what was happening to the 1st group, the 2nd group (discounting what we don't know that happened during the time they were dismissed) had nothing to drink.


So, ideally, the non-caffienated group would leave the room, go to a similar room with another experimenter and undergo the same condition without caffiene (i.e., drink decaf coffee to control for expectancy effects -- the decaf would be a placebo in this case). They, too, would wait one hour then take the test. OR you randomly divide the class into groups and hand out the coffee (some caf, some decaf). Then you wait the requisite amount of time and test all participants at the same time in the same locale.

Here's some other things to consider:

a. You don't have a pre-test measure. You don't know if caffiene has "increased" memory skills of those individual who did and did not consume the caffiene. (The pre/post tests would have to be alternate (comparable) tests, though, and not the same test to control for learning history).

b. The probability that 5 cups of coffee are consumed in one hour is improbable. . .you might also want to look at the time it take caffiene to enter the blood stream (i.e., produce any effect on the body). One cup of coffee has about 115 mg of caffeine, and takes about 20 min to enter the bloodstream -- effects can hang around for about 3 hours. Five cups would put someone's system into overload in an hour.

Answer 2

Your other group really isn't a good control because you have no idea what they've been doing with their time while the coffee drinkers have been under your nose so they can't be getting distracted by real life stuff. I would have the other group stay in a separate room and drink decaf or decaf tea or something. You want to keep things as similar as you possibly can.

You also want to test your groups at the same time if possible. The second group may have done worse simply because it was getting late.

The way the paragraph is written is a little confusing. It doesn't really say whether the test is for short-term memory or if it tests material presented before the groups were split. You need to be very precise in your wording because not all memory is the same.

The others are right about needing to control the caffeine intake prior to the experiment and to account for sex, age, weight in assigning groups. You may also want to give a short questionnaire to find possible confounding variables such as lack of sleep or food, medical problems, etc.

Answer 3

Were the 2nd group given the same time to prepare for the memory tests? Were the class free of caffeine in the first place? Were the 1st and 2nd group isolated? Were they in a controlled environment? Is the average accurate (i.e. outliers)? These could all lead to possible mistakes.

Answer 4

The first mistake is that the second half of the focus group was allowed to leave. Since you have no control over the forces of outside influence and cannot be certain the other group didn't receive any caffine, your study is inconclusive and inaccurate.

The second thing I see wrong is the way they were grouped. They should be of similiar height and weight. Caffine is absorbed into the body and takes affect alot faster in little people than in larger ones.

I'm sure if I picked this apart, I could be here all day, but since I've gotten you started, I hope this helps. Good luck!

Answer 5

well, you can't definatively say how caffeine effects certain people and male and females and the issues of weight (fat vs. skinny)......the test is biased because you have not equally divided the class according to correct proportions to obtain correct results. another could be that certain people have better memory than others and how caffeine would effect these 2 would be biased.....hmmm...6 mistakes...too much time elapsed between the 1st set given caffeine--taking the test--then the 2nd set took the test later....that would effect the findings because they should have been tested at the same moment..

Answer 6

the mistakes are that you have no control group in which to assure that the group that was dismissed didn't go have a cup of coffee, or does it state the time period elapsed between groups taking test.

Answer 7

The only thing I see is that he assumes that the process agrees with his argument. There is no empirical evidence to go by, as in test scores to back up his claim. But that's a guess.

Answer 8

My suggestion is to bail from the course now till now the drop-date. %. up something uncomplicated, like religious study. you will locate lots of tutors over interior the R&S section who might desire to offer help to out.