STEP 1

In this tutorial we will be adding a Visual Search Task to a Psychexp project.

Let us begin by firstly logging in to psychexp and then select "Add New Project" from the menu.

Enter a project name and click submit. (We will call our project "PROJECT 1")

STEP 2

You will be returned to the dashboard, so then find the project you just created in the project list and click "Open".

STEP 3

You are now on the project home page, so click on the "Edit Project" button from the side menu.

STEP 4

When you first create a project in Psychexp a block with one single choice question is inserted by default.

We are going to add the Visual Search Task below this default block by simply clicking the "ADD EXPERIMENT" button and selecting "VISUAL SEARCH TASK" from the list that is displayed.

Build a Visual Search Task in 30 seconds step 4

STEP 5

A fully functional Visual Search Task has now been inserted.

Let's take a look at the structure of the default experiment, and then see how you can customize it to make it your own.

The entire experiment is housed inside of a single block named "Default Block". You can change the name of the block by clicking on the edit (pencil) icon next to the block name.

By clicking on the experiment block settings (cog) icon, you can make changes to the following settings of the experiment;

Left Key
Right Key
Left Target Name
Right Target Name
Max grid cell size [pixels]
Stimulus Font Size
Font Color [Hexadecimal]
Background Color [Hexadecimal]
Feedback Font Size
Heading Font Size
Fixation Point Size
Display Result Page

Next you will see a text only information page that is shown to the participant before the experiment begins. This page is fully customizable by clicking the edit (pencil) icon. You can also add extra pages by clicking the "Add Text Only Page" Button.

Following the information page there are four sections. These four sections include all the components that will be used to build the flow of the experiment.

TARGET: You can add as many text or image stimulus as you require to the target category.
DISTRACTOR: You can add as many text or image stimulus as you require to the distractor category.
MESSAGES: You can create as many messages as is required. These messages will be displayed to the participant during the experiment. At what point they will be displayed during the expeirment is set in the FLOW SECTION explained below.
FIXATION POINT: The fixation point is displayed prior to the stimulus being shown (optional). You can add as many text or image fixation points as you wish here and then allocate them in the FLOW SECTION explained below.

STEP 6

Now we will look at the flow of the Visual Search Task. The flow comprises of Flow blocks and sub-flow blocks. The sub-flow blocks within a flow block can be randomized by clicking the Flow Block settings (cog) icon

You can add as many blocks or sub-flow blocks as you wish to create your desired experiment.

The sub-flow block contains the following components.

Start Message: The start message is shown prior to the group of trials set in this sub-flow block. (optional)
Display Target above start message: The target you select from the dropdown menu will be displayed above the start message. Caution: If the target you select is not being used in any of the sets within this sub-flow block, the experiment will break.
Reverse Headings: Setting this to yes will put the Left Target Name on the right hand side and the Right Target Name on the left hand side. (The left and right target names are set in the experiment block which is at the very top of the experiment)
Fixation Point: Set the number of milliseconds to display by clicking the settings (cog) icon.
Multiple sets: The contents of each set is explained in detail below.

Each set contains the following components.

Target: Set the target #id and the number of targets to include in the set from the two dropdowns.
Distractor: You can set up to 3 types of distractors in the same set. Set the distractor #id and the number of distractors to include in the set from the six dropdowns.

If the total of all targets and distractors selected in one set is greater than the X and Y axis grid, the set will display red and the experiment will break. (example: X axis = 3, Y axis = 4, Grid Total = 12. Number of Targets set = 1, Distractors set = 12, Total = 13)

If a target or distractor #id is selected but the number is set to zero, the set will display yellow and the experiment will break. The same will happen if the reverse is set (#id = None, but a number other than zero is selected)

By clicking the sub-flow block settings (cog) icon, you can change the following settings.

Practice: Unchecking this box will make the sets displayed in this sub-flow block a test. The average response time for test sets only are included in the dataset.
Interstimulus interval (ms): This is the number of millseconds a blank interval is displayed prior to each fixation point being displayed.
Feedback interval (ms): The feedback interval sets the length of time a red cross or green circle is displayed to let the respondent know if they got the answer correct or not. Setting this to zero will stop any feedback from being displayed.
Correct value: This value is used to calculate a correct or incorrect answer. (Possible combinations: > N, >= N, < N, <= N, = N)

After you have made changes to the default experiment, you can see a live preview of the experiment by clicking the "Preview" button at the bottom of the page. You can preview the project as many times as you want. The preview screens are identical to the screens your participants will see when you distribute your project, however the data from a preview is not saved in the dataset.

Build a Visual Search Task in 30 seconds step 6

STEP 7

Once you are happy with the design of your experiment you can then adjust the flow of your entire project by editing or deleting the default survey question block that was inserted when you initially made the project. You can also add more survey question blocks or even other experiment blocks under your current experiment by simply clicking on the "ADD BLOCK" or "ADD EXPERIMENT" buttons at the bottom of the page. The combination of experiments and survey questions that you can achieve is only limited by your own imagination!

PRO TIP: Changing the order of the flow of survey question blocks and experiment blocks in your project is as easy as using the up and down arrow buttons that can be found at the top of each survey question or experiment block.

Before distributing your project to your participants be sure to adjust the project settings by clicking on "Project Settings" in the menu.

These are just a few of the many settings you can adjust:

Single or multiple time project participation
Require email registration
Set start and finish dates for participation
Record geolocation
Registration Page Logo

Build a Visual Search Task in 30 seconds step 9

STEP 8

When you are ready to distribute your project to your participants, click on "QR code" in the menu to get the URL link or QR code for this project

PRO TIP: Once a participant has responded to your survey or experiment, you are no longer able to make changes to the project in the "Edit Project" screen. Use the project "PREVIEW" button extensively to check your project prior to distributing it to any participants.

To view the data collected from your participants, click on "Dataset" in the menu.

The dataset will be downloaded in excel format

The default procedure for the visual search task refers to the following paper. However, partial changes have been made to the experimental procedures and stimulus:
Horstmann, G. (2009). Visual search for schematic affective faces: Stability and variability of search slopes with different instances. Cognition and Emotion, 23(2), 355-379.

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Build a Visual Search Task in 30 seconds Fully Customizable