The wording of the task given to a person has a strong influence on their behavior and eye movements which affects the results of the study.
You get what you ask for
In Alfred Yarbus's research, the same person examined the reproduction of Ilya Repin's painting “Unexpected visitor” given different instructions for each trial. Analysis of eye movements shows that the observer's attention is focused on those elements that contain or may contain, in their opinion, the necessary information for the current task.
1 — free examination, no instructions given.
2 — evaluate the material situation of the family.
3 — determine the age of the people pictured.
4 — figure out what the family was doing before the arrival of the visitor.
5 — remember how people were dressed.
6 — remember the location of people and objects in the room.
7 — estimate how much time the visitor was absent from the family.
Start with the goal
The very first step in writing better instructions is clearly defining the goal of your study. What is the purpose of your experiment? What exactly are you trying to find out and why?
Think about the circumstances under which your test participant would see your media in real life. How long is your customer intended to interact with your product? Are you wondering if it's noticeable out of the corner of your eye or do you care about how informative your packaging is? Do you want to know how long your customers actually watch your advertisement video before pressing skip?
Answering even simple questions like these will make it much easier to come up with precise and easy to understand instructions.
Make the task realistic
In all our studies we strive to recreate settings that are as close to real life as possible. When your test participants understand the context, they behave in a more realistic manner and provide more useful feedback.
Although free examination may seem like a no-brainer at first glance, it is important to remember that people very rarely do anything without a goal or motivation in mind. Therefore, even a simple task like "examine the painting" may be more representative of a real life situation in which a customer interacts with your product unprompted.
Consider the difference:
Please look at this web page as you normally would.
You are looking for a gift for your friend. See if anything catches your eye.
Clarity over clutter
Don’t make anything more complicated than it needs to be. Remember, if your scenario needs an elaborate explanation, it is probably not a realistic scenario.
Keep your instructions short and to the point, avoiding marketing language and overly complicated scenarios. Make sure that you are using language that is appropriate for your audience. Do not use professional terminology if your intended audience is the general public.
Consider the difference:
Soon you will see a product page in an e-commerce store.
Look at the web page.
Consider providing the participants with an outline of the experiment, informing them about the nature of the task and the time given to complete it. However, depending on the goal of your experiment, you might choose to not reveal the time constraint to your participants.
Conducting a pilot study
The temptation to publish your experiment the second you are done writing up the instructions is great, but it is important to take a minute to test and a get a second opinion first. Try running the experiment on yourself or ask a colleague to take a look; this way you will see if your instructions are lacking something or are simply too long to finish reading in time before exposure begins.