Chapter 1. Attentional Blink

1.1 Introduction

Cognitive Tool Kit

Attentional Blink

In this experiment, you will be presented with a string of letters, one at a time, in the same place on the screen. The letters will come at you rapidly, so be ready. In the midst of this string of letters, a J or a K or both will be presented. Your job will be to report if you see a J, a K, or both a J and a K. Can you see these letters? Good luck!

1.2 Experiment Setup

1.3 Instructions


You will need to press the space bar to begin the experiment. At the beginning of each trial, a fixation mark will appear. Please look at this mark. After it is removed, letters will be presented rapidly in the same location as the fixation mark. There are two targets: J and K.

Either one or both can be present in each trial. After the sequence is done, type the J key if you saw the J and type the K key if you saw the K. If you see neither letter, you do not need to type either letter and may just press Enter. You may type the letters you see in any order. Your responses will be displayed at the bottom of the screen. If you make a mistake, you may use the delete key to remove a letter. If you need to repeat a trial because something distracted you, press the R key and the trial will be repeated at a random time later. Press the space bar to proceed to the next trial.

1.4 Experiment

Begin Experiment

1.5 Results


1.6 Debriefing


We cannot process everything coming at us. Our cognitive mechanisms must select some stimuli to process. This selection is called attention. The limits that influence our attentional ability are a fundamental fact of the way we experience the world and a key area of study in cognitive psychology. Think of how different your experience would be if you could process all of the conversations going on at a party around you.

This experiment is designed to examine one limit on attention. As a simple example, it is easy to see that if I am looking to the left, I will not clearly see and probably not pay attention to what is going on to the right of me. The focus of this experiment is on a different aspect of attention. All of the stimuli were presented, rapidly, right in front of you. The presentation of stimuli is called Rapid Visual Serial Presentation (RSVP). You don’t move your eyes and the stimuli always fall on your fovea, where you have your best vision.

In this experiment, the trials when both the J and the K are presented are the trials we are most interested in. Let us consider the two following sequences of letters (remember that they would be always presented in the same place):

L R T J K P ….
L R T J P D I F V M K ….

In the first list, the K immediately follows the J. In the second list, the K follows a good long while after the J in the list. From the findings above, the K in the first list is a lot harder to detect than the K in the second list! Thinking through these results suggests that when you see the J, you have to do some mental processing to note that you detected the J so that you remember to type it in at the end of the trial. This processing takes time; ; as a result, you miss the K. There are different theories about what this processing is, but it requires attention to do this processing, and while you are doing that processing, you cannot do the additional processing needed to note that you saw the K. That is why this response is called an attentional blink.


Raymond, J. E., Shapiro, K. L., & Arnell, K. M. (1992). Temporary suppression of visual processing in an RSVP task: An attentional blink? Journal of Experimental Psychology: Human Perception and Performance,18(3), 849-860.

Raymond, J. E., Shapiro, K. L., & Arnell, K. M. (1995). Similarity determines the attentional blink. Journal of Experimental Psychology: Human Perception and Performance, 21(3), 653-662.

1.7 Quiz


Question 1.1

The independent variable is the value that is changed by the experimenter. In this experiment, this variable is the time between the presentation of the two targets.

Question 1.2

The dependent variable is the value the experimenter collects to indicate how you performed in the experiment. In this case, we determined how many targets you correctly reported having seen. So the correct answer is percent correct.

Question 1.3

This experiment examines how we are able to process only some stimuli at a time. The ability to select some stimuli to process and not others is called attention.

Question 1.4

The standard finding is that the longer the separation between targets, the more often the second target is recalled.

Question 1.5

Raymond and colleagues (1992) proposed the name attentional blink for this effect in the title of their paper.