What we’ll cover
- What is the Posner cueing task and how can you use it in your research
- How to run the Posner cueing task in Testable starting from our ready-made template
- How you can customise key parameters and play around with different options
- How to collect data and interpret the results
If you never worked with Testable before, you can check out our 3-minute introduction here
What is the Posner cueing task and how can you use it in your own research
We have become used to talk about attention in terms of the forces that act on it. We may say that the sound or sight of a Twitter notification ‘pulled’ our attention away from our work. Or we might be ‘glued’ to a captivating story in a book.
Almost as if subject to physical forces, our attention seems to have a ‘ballistic’ quality, as Martin Posner (1980) himself expressed it. Even though orienting our attention often coincides with the gaze of our eyes, it intuitively seems that we can focus it independently and move it around our visual field, even if our eyes remain still. This is what we mean when we say we are glancing ‘from the corner of our eyes’.
The aim of the Posner cueing task is to demonstrate and measure the movement of attention across the visual field without moving the eyes. This particular demo of the Posner cueing tasks is an example of an exogenous cueing paradigm. It allows you to measure the pull of attention due to external, visual stimuli (a flashing cue). In this guide, you will also learn how to adapt the template to create an endogenous version to measure attentional movement caused by mental (endogenous) cues.
The Posner cueing task and its variations have become a staple tool in understanding the spatial attention of healthy individuals. It also helps pinpointing specific attentional deficits in individuals with neural damage.
The Posner cueing task measures how attention can move across our visual field even when our eyes remain fixated.
How does the Posner cueing task work?
In this task participants need to indicate which side a target appears on by pressing the corresponding arrow key as quickly as possible. Before the target appears, one or both of the squares light up, thereby ‘cueing’ one or both locations. Participants are told to ignore this cue. This task measures the degree to which participants get distracted by the cue anyway. This can be beneficial when the cue is predictive, and harmful when it is not.
At the beginning of each trial, the two empty boxes with a central fixation cross are shown for a time varying between 500-1000ms. Then the cue flashes up for 100ms. The target is then immediately shown in one of the locations for a time between 100 and 500ms. The timing variations help to avoid anticipated responses and forces participants to pay more attention throughout the experiment.
In our demo task, participants get to practice the task first before doing the 120 experimental trials. In practice trials they receive feedback after their correct and incorrect responses.
During the experiment, there are three possible scenarios.
- The target appears in the same square that just lit up (valid cue condition).
- The target appears in the opposite square from the one that just lit up (invalid cue condition)
- Both squares light up, and the target appears in one of the squares (neutral condition)
The core prediction we make for performance in the Posner cueing task is that the cue will draw participants’ attention, even when instructed to ignore it. That means that we expect faster and more accurate responses for validly cued trials. Here the brain is given a head start to prepare a response for that side. Conversely, responses should be slower for invalidly cued trials. Here the brain needs to first suppress the incorrectly prepared response before initiating a response for the opposite side. Neutrally cued trials should be unbiased, so reaction times should fall in between.
What key behaviours does the Posner cueing task measure
The Posner cueing task is designed to measure the time it takes to re-orient attention from one side of the visual field to the other, when a misleading cue was given. It also measures how much time is saved if attention was already drawn to the side of the screen where the target will be shown. This allows to separately measure the following mental processes:
- Orienting attention (RT of valid trials – RT of neutral trials). How long does it take to move the attentional focus from a neutral, to a task-relevant point?
- Disengaging attention (RT of invalid trials – RT of neutral trials) – How long does it take to disengage attention from an irrelevant location, before being able to move to a relevant one?
- Moving attention across the visual field (RT of invalid trials – RT of valid trials) – How long does it take for the focus of attention to move to the relevant side of the visual field
Run this experiment in Testable from our ready made template
We have created a template for the Posner cueing task in Testable for you that you can access from our Library. It is set-up and ready to go and you can start collecting data straight away by sending the experiment link to your participant. Experiments in Testable will run in every browser, which makes it very easy to collect data both in the lab as well as online.
How to customise key parameters and play around with different options
Experiments in Testable are fully customisable and you will not need to write a single line of code to edit them. The heart of each experiment is what we call the trial file. The trial file contains all information that Testable needs to run the experiment in a simple spreadsheet, that you can edit with any spreadsheet editor you like, such as Google Sheets, Excel or Testable’s in-built preview editor.
To change any part of your experiment, you only need to change the values in the trial file.
Here are a few examples of changes you might want to make to the Posner cueing task:
Create an ‘endogenous’ version of the Posner cueing task
Our demo experiment is the exogenous version of the Posner cueing task. That means that the cue directs attention physically to (or away from) the space where the target will appear. Another way of using this paradigm is by using an arrow that flashes just above the central fixation cross (see below). This type of cue doesn’t directly capture visual attention, but instead suggests a position to the viewer. That means that the impulse to shift ones visual attention to either side is triggered by an internal (endogenous) mechanism.
To accomplish this in Testable you need to:
- Generate a new set of cueing stimuli, with an arrow that points either left or right above the central cross
- Upload the new stimuli to the projects’ stimuli library
- Change the filenames in the stim2 column in the trial file. As the cue is shown in second place during the trial (after the neutral fixation image, stored in column stim1), it is stored in column stim2
All remaining parameters, like randomisation, timings and responses remain the same.
Collect data by sending the experiment link to your participants
After importing this template to your library, you can collect data for your experiment by sharing the unique experiment link (i.e. tstbl.co/xxx-xxx) with your participants. Once participants complete the experiment, their results will appear in the ‘Results’ section of your experiment.
Working with results from the Posner cueing task
Result files from the Posner cueing task contain all information from your trial file and additional columns with participants’ responses. The column from the results that will be most useful for your analysis is the RT (response time) column and also the correct (accuracy) column.
In the trial file we have also defined one custom columns called condition1. We have used it to mark the trials either to have a valid cue (cue on the same side as target), invalid cue (cue on the opposite side as target) or neutral (cues on both sides). These columns do not affect the experiment in any way, but help us with data analysis as we can now easily group our results by their experimental condition.
There are different ways to look at the combination of accuracy and response time between the two relevant conditions. The simplest is to only include the data from correct trials:
- Using the correct column, filter out all incorrect trials (marked with 0)
- Using the condition1 column, group the results from the valid cue, invalid cue (counterbalanced left and right) and neutral trials
- Compute the average response time for each condition stored in the RT column
Reaction times should be fastest for validly cued trials. Attention has already been oriented to the correct target location and the target can be detected quickly. In the neutral condition, attention first needs to be oriented to the target location, after which the target can be detected and responded to. Finally, invalidly cue trials should have the slowest reaction times (and worst accuracy) as attention first needs to be disengaged from the inappropriate location, then deployed towards the correct target location before detection and response to the target can occur.
To allow participants to see their results instantly, you could also try Testable’s visualisation feature. You can find it in the ‘Visuals’ tab of your project setup. It allows you to plot or create a table for a key variable (in this case RT_correct, which is the response time for correct trials) that will be automatically grouped by the condition1 labels.
Once you have collected data from multiple participants, you can also use Testable’s ‘wide format’ feature, that allows you to automatically collate all individual result files into a single file. In wide format results every participant’s data is represented as one row in the data. This makes it easily compatible with statistical analysis packages like R or SPSS where you can assess the statistical significance of any differences you may find.
Posner, M. I. (1980). Orienting of attention. Quarterly journal of experimental psychology, 32(1), 3-25.
Posner, M. I. (2016). Orienting of Attention: Then and Now. Quarterly Journal of Experimental Psychology, 69(10), 1864–1875. doi:10.1080/17470218.2014.937446