38  Formative PsychoPy quiz

🏠 Self-study

This is a formative PsychoPy quiz about content covered in Lab 6. You might find it helpful to return to these questions when revising for the January exam.

What is the relationship between “conditions” and “parameters” in a PsychoPy condition file?

Parameters are columns defining information about conditions. Conditions are the rows below the header.Parameters and conditions are different names for the same thing.Conditions are columns defining information about parameters. Parameters are the rows below the header.Parameters and conditions must always be equal in number.

The correct answer is that parameters are columns defining information about conditions, and conditions are the rows below the header. For example, parameters like ‘stim’ or ‘corrAns’ provide information about each condition (trial) in the experiment.

Which of the following names can you use in the header row of a conditions file? Select all that apply.

1st_stimstim(1)stimmy_stimmyStimstim 1stim1my-stim

Only letters, numbers, and underscores are allowed. In addition, numbers must not come first.

You want this Image component to present images in your experiment:

Your images are inside a folder called “images” in the main experiment folder. The images are called left.png and right.png.

What is the correct setup for the input file?:

The correct option is:

ABCDEF

Variable names in the Excel file header row must not use the dollar sign. The Image component uses “stim” as variable name, so the corresponding column in the Excel file must use “stim” as well. The images are in a subfolder, so the path to that subfolder must be added. The subfolder is called “images”, not “image”.

What is the main advantage of using loops in PsychoPy compared to creating individual routines for each trial? Select all that apply.

Loops make the experiment run faster on the computer.Loops allow for efficient experiment creation by defining a trial template that can be repeated while updating information.Loops allow you to skip certain routines during the experiment.Loops automatically randomise all components within each routine.

On the one hand, loops allow for efficient experiment creation by defining a trial template that can be repeated while updating information. Rather than creating hundreds of individual trial routines, loops let you create one template and repeat it with different parameters. On the other hand, they also make it easy to skip parts of the experiment by surrounding these parts with a loop and setting “Num. repeats” to 0.

You present three different geometric shapes in an experiment, one on each trial. The shapes defined in your input file are: circle, square, triangle. There are two repetitions of the input file, so six trials overall. The shapes are presented in the following order: circle, square, triangle, triangle, circle, square. What can you conclude about the “Loop type” settings? Select all that apply.

Loop type cannot be sequential.Loop type might be sequential.Loop type must be sequential.Loop type cannot be random.Loop type might be random.Loop type must be random.Loop type cannot be fullRandom.Loop type might be fullRandom.Loop type must be fullRandom.

Loop type cannot be sequential as the order for the two repeats is not the same. Loop type might be random as the shapes are presented in groups: (circle, square, triangle) and (triangle, circle, square). Loop type might also be fullRandom, because a fullRandom order could of course result in a grouped order (there is just no guarantee that it will).

You want to present the letter K on half of your trials. The other half of the trials should present the letter G. These are your Text component properties:

Will this work?

Yes, I just need to add a second Text component that presents the letter G.No, because the Text field should say “$K”.No, the Text field is not using a variable. This Text component will always present the letter K.Yes, I’m using “set every repeat”, so the letter can be changed.

This will not work because the Text field is not using a variable. Using “set every repeat” is necessary, but not sufficient. Adding a second Text component will not solve the problem either (it would simply present an additional letter). Using “$K” will also not help as the relevant part is to use a dollar sign and a variable name, not to prepend the actual stimulus with a dollar sign.

To modify the text presented by a Text component from one trial to the next, you must do the following:

1. The variable name in the Text field must be preceded by: A dollar sign ($).A percent sign (%).An ampersand (&).
2. The variable name in the Text field must match: The file name of the input file.The name of the Text component.A column header in the input file.
3. You should select the following option: Constant.Set every repeat.Set every frame.

The variable name in the Text field must be immediately preceded by a $ sign, with no space in between. The variable name must match the relevant column header in the input file. “Set every repeat” should be selected. While “Set every frame” would also work, it is a poor choice if a stimulus only needs to be updated only once at the beginning of the trial.

Which of the following statements about component properties in PsychoPy are true? Select all that apply.

Constants can be used for properties that change across trials.If you want to change a component property across trials, it must be defined using a variable.Properties that stay the same across all trials must always be variables.Using variables allows for dynamic changes in component properties during the experiment.

The correct answers are that if you want to change a component property across trials, it must be defined using a variable, and using variables allows for dynamic changes in component properties during the experiment.