Within-Subject Design Experiments

A在主题设计中是一种实验设计，所有参与者都暴露于每种治疗或条件。

术语“治疗”用于描述不同的levels of the independent variable, the variable that's controlled by the experimenter. In other words, all of the subjects in the study are treated with the critical variable in question.

概要

Let's imagine that you are doing an experiment on exercise and记忆。For your independent variable, you decide to try two different types of exercise: yoga and jogging.

Instead of breaking participants up into two groups, you have all the participants try yoga before taking a memory test. Then, you have all the participants try jogging before taking a memory test. Next, you compare the test scores to determine which type of exercise had the greatest effect on performance on the memory tests.

Advantages

Why exactly would researchers want to use a within-subject design? One of the most significant benefits of this type of experimental design is that it does not require a large pool of participants. A similar experiment in a between-subject design, which is when two or more groups of participants are tested with different factors, would require twice as many participants as a within-subject design.

A within-subject design can also help reduce errors associated with individual differences. In a between-subject design where individuals arerandomly assigned弗吉尼亚州的独立riable or treatment, there is still a possibility that there may be fundamental differences between the groups that could impact the experiment's results.

缺点

This type of experimental design can be advantageous in some cases, but there are some potential drawbacks to consider. A major drawback of using a within-subject design is that the sheer act of having participants take part in one condition can impact the performance or behavior on all other conditions, a problem known as a carryover effect.

So for instance in our earlier example, having participants take part in yoga might have an impact on their later performance in jogging and may even affect their performance on later memory tests.

Finally, performance on subsequent tests can also be affected by practice effects. Taking part in different levels of the treatment or taking the measurement tests several times might help the participants become more skilled.

这意味着它们可能能够弄清楚如何游戏结果，以便在实验上做得更好。这可以歪斜结果并使难以确定任何效果是否是由于治疗的不同或仅仅是实践的结果。