Introduction

The Attentional Blink (AB) phenomenon was first described by Raymond, Shapiro and Arnell in 1992.

In short, this is what the task is about:

  • People are told to find a specific stimulus, the target stimulus (e.g., the letter L).

  • The target stimulus is not always shown.

  • Multiple stimuli are shown very briefly.

The AB phenomenon is the following: People have a difficulty observing the target when it follows a non-target and the time between the first and second stimulus is between 0 and 300 ms (Experiment 2., Duncan et al., 1994).

About this implementation

This implementation is close to experiment 2 of Duncan, Ward & Shapiro (1994) in Nature.

This implementation has a long table. Read below why.

There are two ways in PsyToolkit of managing conditions.

  1. You have a line for each possible stimulus/response association in the table, like in this, or in library version of the visual search task. This is easier to program, but if you have many different combinations of stimuli and responses or times, you need an efficient piece of code to create the table (although you can type it in all manually). In this task, the file ab-table.r creates that using the statistical programming language R (which has its own PsyToolkit lesson).

  2. You can create trial conditions ad hoc using some coding. This can create more efficient code, but it really depends on the type of paradigm. If you do this, it will be hard to have exactly the same number of trials in all conditions.

No matter what, programming cognitive psychological experiments require some coding. Of course, you can just use a library example.

Run the demo

In this example, you will use the keys b and n to indicate if you have seen the target stimulus (an L shape) or not. You will get feedback if you did it correctly or not and if the L shape was there or not. It is actually quite a difficult task.

Click here to run a demo

Data output file

In PsyToolkit, the data output file is simply a textfile. The save line of the PsyToolkit experiment script determines what is being saved in the data output file. Typically, for each experimental trial, you would have exactly one line in your text file, and each number/word on that line gives you the information you need for your data analysis, such as the condition, response speed, and whether an error was made.

Meaning of the columns in the output datafile. You need this information for your data analysis.

Colum Meaning

1

Time between stimulus 1 and 2. Negative numbers mean that the target came first (if a t all). The negative numbers follow the convention of Duncan et al., 1994.

2

Stimulus 1

3

Stimulus 2

4

x pos of stimulus 1

5

y pos of stimulus 2

6

target present (1) or not (2)

7

response time (ms)

8

status (1=correct, 2=wrong, 3=slow)

PsyToolkit code

Click to expand the PsyToolkit script code (part of zip file below) 
# attentional blink
# based on experiment 2 of Duncan, Ward & Shapiro (1994) in Nature.

options
  bitmapdir stimuli  # location of the bitmaps

fonts
  arial 18
  
bitmaps
  t1                 # target
  n1                 # nontarget1
  n2                 # nontarget2
  n3                 # nontarget3
  box                # box stimulus appear in
  mask               # mask
  fix                # fixation point
  info1              # title and information screens
  info2
  info3
  help               # gives help following error
  correct_l
  wrong_l  
  correct_no_l
  wrong_no_l  

## note, the negate time means that the target comes first, at least
## if there is a target. It is really about the stimulus order.

table abtable # table created with the provided R file ab-table.r
  0   n1 t1 -200 -200 1 "0 n1 t1 -200 -200 1" 
  100 n1 t1 -200 -200 1 "100 n1 t1 -200 -200 1" 
  100 t1 n1 -200 -200 1 "-100 t1 n1 -200 -200 1" 
  196 n1 t1 -200 -200 1 "196 n1 t1 -200 -200 1" 
  196 t1 n1 -200 -200 1 "-196 t1 n1 -200 -200 1" 
  280 n1 t1 -200 -200 1 "280 n1 t1 -200 -200 1" 
  280 t1 n1 -200 -200 1 "-280 t1 n1 -200 -200 1" 
  430 n1 t1 -200 -200 1 "430 n1 t1 -200 -200 1" 
  430 t1 n1 -200 -200 1 "-430 t1 n1 -200 -200 1" 
  590 n1 t1 -200 -200 1 "590 n1 t1 -200 -200 1" 
  590 t1 n1 -200 -200 1 "-590 t1 n1 -200 -200 1" 
  900 n1 t1 -200 -200 1 "900 n1 t1 -200 -200 1" 
  900 t1 n1 -200 -200 1 "-900 t1 n1 -200 -200 1" 
  0   n1 t1 -200 200 1 "0 n1 t1 -200 200 1" 
  100 n1 t1 -200 200 1 "100 n1 t1 -200 200 1" 
  100 t1 n1 -200 200 1 "-100 t1 n1 -200 200 1" 
  196 n1 t1 -200 200 1 "196 n1 t1 -200 200 1" 
  196 t1 n1 -200 200 1 "-196 t1 n1 -200 200 1" 
  280 n1 t1 -200 200 1 "280 n1 t1 -200 200 1" 
  280 t1 n1 -200 200 1 "-280 t1 n1 -200 200 1" 
  430 n1 t1 -200 200 1 "430 n1 t1 -200 200 1" 
  430 t1 n1 -200 200 1 "-430 t1 n1 -200 200 1" 
  590 n1 t1 -200 200 1 "590 n1 t1 -200 200 1" 
  590 t1 n1 -200 200 1 "-590 t1 n1 -200 200 1" 
  900 n1 t1 -200 200 1 "900 n1 t1 -200 200 1" 
  900 t1 n1 -200 200 1 "-900 t1 n1 -200 200 1" 
  0   n1 t1 200 -200 1 "0 n1 t1 200 -200 1" 
  100 n1 t1 200 -200 1 "100 n1 t1 200 -200 1" 
  100 t1 n1 200 -200 1 "-100 t1 n1 200 -200 1" 
  196 n1 t1 200 -200 1 "196 n1 t1 200 -200 1" 
  196 t1 n1 200 -200 1 "-196 t1 n1 200 -200 1" 
  280 n1 t1 200 -200 1 "280 n1 t1 200 -200 1" 
  280 t1 n1 200 -200 1 "-280 t1 n1 200 -200 1" 
  430 n1 t1 200 -200 1 "430 n1 t1 200 -200 1" 
  430 t1 n1 200 -200 1 "-430 t1 n1 200 -200 1" 
  590 n1 t1 200 -200 1 "590 n1 t1 200 -200 1" 
  590 t1 n1 200 -200 1 "-590 t1 n1 200 -200 1" 
  900 n1 t1 200 -200 1 "900 n1 t1 200 -200 1" 
  900 t1 n1 200 -200 1 "-900 t1 n1 200 -200 1" 
  0   n1 t1 200 200 1 "0 n1 t1 200 200 1" 
  100 n1 t1 200 200 1 "100 n1 t1 200 200 1" 
  100 t1 n1 200 200 1 "-100 t1 n1 200 200 1" 
  196 n1 t1 200 200 1 "196 n1 t1 200 200 1" 
  196 t1 n1 200 200 1 "-196 t1 n1 200 200 1" 
  280 n1 t1 200 200 1 "280 n1 t1 200 200 1" 
  280 t1 n1 200 200 1 "-280 t1 n1 200 200 1" 
  430 n1 t1 200 200 1 "430 n1 t1 200 200 1" 
  430 t1 n1 200 200 1 "-430 t1 n1 200 200 1" 
  590 n1 t1 200 200 1 "590 n1 t1 200 200 1" 
  590 t1 n1 200 200 1 "-590 t1 n1 200 200 1" 
  900 n1 t1 200 200 1 "900 n1 t1 200 200 1" 
  900 t1 n1 200 200 1 "-900 t1 n1 200 200 1" 
  0   n2 t1 -200 -200 1 "0 n2 t1 -200 -200 1" 
  100 n2 t1 -200 -200 1 "100 n2 t1 -200 -200 1" 
  100 t1 n2 -200 -200 1 "-100 t1 n2 -200 -200 1" 
  196 n2 t1 -200 -200 1 "196 n2 t1 -200 -200 1" 
  196 t1 n2 -200 -200 1 "-196 t1 n2 -200 -200 1" 
  280 n2 t1 -200 -200 1 "280 n2 t1 -200 -200 1" 
  280 t1 n2 -200 -200 1 "-280 t1 n2 -200 -200 1" 
  430 n2 t1 -200 -200 1 "430 n2 t1 -200 -200 1" 
  430 t1 n2 -200 -200 1 "-430 t1 n2 -200 -200 1" 
  590 n2 t1 -200 -200 1 "590 n2 t1 -200 -200 1" 
  590 t1 n2 -200 -200 1 "-590 t1 n2 -200 -200 1" 
  900 n2 t1 -200 -200 1 "900 n2 t1 -200 -200 1" 
  900 t1 n2 -200 -200 1 "-900 t1 n2 -200 -200 1" 
  0   n2 t1 -200 200 1 "0 n2 t1 -200 200 1" 
  100 n2 t1 -200 200 1 "100 n2 t1 -200 200 1" 
  100 t1 n2 -200 200 1 "-100 t1 n2 -200 200 1" 
  196 n2 t1 -200 200 1 "196 n2 t1 -200 200 1" 
  196 t1 n2 -200 200 1 "-196 t1 n2 -200 200 1" 
  280 n2 t1 -200 200 1 "280 n2 t1 -200 200 1" 
  280 t1 n2 -200 200 1 "-280 t1 n2 -200 200 1" 
  430 n2 t1 -200 200 1 "430 n2 t1 -200 200 1" 
  430 t1 n2 -200 200 1 "-430 t1 n2 -200 200 1" 
  590 n2 t1 -200 200 1 "590 n2 t1 -200 200 1" 
  590 t1 n2 -200 200 1 "-590 t1 n2 -200 200 1" 
  900 n2 t1 -200 200 1 "900 n2 t1 -200 200 1" 
  900 t1 n2 -200 200 1 "-900 t1 n2 -200 200 1" 
  0   n2 t1 200 -200 1 "0 n2 t1 200 -200 1" 
  100 n2 t1 200 -200 1 "100 n2 t1 200 -200 1" 
  100 t1 n2 200 -200 1 "-100 t1 n2 200 -200 1" 
  196 n2 t1 200 -200 1 "196 n2 t1 200 -200 1" 
  196 t1 n2 200 -200 1 "-196 t1 n2 200 -200 1" 
  280 n2 t1 200 -200 1 "280 n2 t1 200 -200 1" 
  280 t1 n2 200 -200 1 "-280 t1 n2 200 -200 1" 
  430 n2 t1 200 -200 1 "430 n2 t1 200 -200 1" 
  430 t1 n2 200 -200 1 "-430 t1 n2 200 -200 1" 
  590 n2 t1 200 -200 1 "590 n2 t1 200 -200 1" 
  590 t1 n2 200 -200 1 "-590 t1 n2 200 -200 1" 
  900 n2 t1 200 -200 1 "900 n2 t1 200 -200 1" 
  900 t1 n2 200 -200 1 "-900 t1 n2 200 -200 1" 
  0   n2 t1 200 200 1 "0 n2 t1 200 200 1" 
  100 n2 t1 200 200 1 "100 n2 t1 200 200 1" 
  100 t1 n2 200 200 1 "-100 t1 n2 200 200 1" 
  196 n2 t1 200 200 1 "196 n2 t1 200 200 1" 
  196 t1 n2 200 200 1 "-196 t1 n2 200 200 1" 
  280 n2 t1 200 200 1 "280 n2 t1 200 200 1" 
  280 t1 n2 200 200 1 "-280 t1 n2 200 200 1" 
  430 n2 t1 200 200 1 "430 n2 t1 200 200 1" 
  430 t1 n2 200 200 1 "-430 t1 n2 200 200 1" 
  590 n2 t1 200 200 1 "590 n2 t1 200 200 1" 
  590 t1 n2 200 200 1 "-590 t1 n2 200 200 1" 
  900 n2 t1 200 200 1 "900 n2 t1 200 200 1" 
  900 t1 n2 200 200 1 "-900 t1 n2 200 200 1" 
  0   n3 t1 -200 -200 1 "0 n3 t1 -200 -200 1" 
  100 n3 t1 -200 -200 1 "100 n3 t1 -200 -200 1" 
  100 t1 n3 -200 -200 1 "-100 t1 n3 -200 -200 1" 
  196 n3 t1 -200 -200 1 "196 n3 t1 -200 -200 1" 
  196 t1 n3 -200 -200 1 "-196 t1 n3 -200 -200 1" 
  280 n3 t1 -200 -200 1 "280 n3 t1 -200 -200 1" 
  280 t1 n3 -200 -200 1 "-280 t1 n3 -200 -200 1" 
  430 n3 t1 -200 -200 1 "430 n3 t1 -200 -200 1" 
  430 t1 n3 -200 -200 1 "-430 t1 n3 -200 -200 1" 
  590 n3 t1 -200 -200 1 "590 n3 t1 -200 -200 1" 
  590 t1 n3 -200 -200 1 "-590 t1 n3 -200 -200 1" 
  900 n3 t1 -200 -200 1 "900 n3 t1 -200 -200 1" 
  900 t1 n3 -200 -200 1 "-900 t1 n3 -200 -200 1" 
  0   n3 t1 -200 200 1 "0 n3 t1 -200 200 1" 
  100 n3 t1 -200 200 1 "100 n3 t1 -200 200 1" 
  100 t1 n3 -200 200 1 "-100 t1 n3 -200 200 1" 
  196 n3 t1 -200 200 1 "196 n3 t1 -200 200 1" 
  196 t1 n3 -200 200 1 "-196 t1 n3 -200 200 1" 
  280 n3 t1 -200 200 1 "280 n3 t1 -200 200 1" 
  280 t1 n3 -200 200 1 "-280 t1 n3 -200 200 1" 
  430 n3 t1 -200 200 1 "430 n3 t1 -200 200 1" 
  430 t1 n3 -200 200 1 "-430 t1 n3 -200 200 1" 
  590 n3 t1 -200 200 1 "590 n3 t1 -200 200 1" 
  590 t1 n3 -200 200 1 "-590 t1 n3 -200 200 1" 
  900 n3 t1 -200 200 1 "900 n3 t1 -200 200 1" 
  900 t1 n3 -200 200 1 "-900 t1 n3 -200 200 1" 
  0   n3 t1 200 -200 1 "0 n3 t1 200 -200 1" 
  100 n3 t1 200 -200 1 "100 n3 t1 200 -200 1" 
  100 t1 n3 200 -200 1 "-100 t1 n3 200 -200 1" 
  196 n3 t1 200 -200 1 "196 n3 t1 200 -200 1" 
  196 t1 n3 200 -200 1 "-196 t1 n3 200 -200 1" 
  280 n3 t1 200 -200 1 "280 n3 t1 200 -200 1" 
  280 t1 n3 200 -200 1 "-280 t1 n3 200 -200 1" 
  430 n3 t1 200 -200 1 "430 n3 t1 200 -200 1" 
  430 t1 n3 200 -200 1 "-430 t1 n3 200 -200 1" 
  590 n3 t1 200 -200 1 "590 n3 t1 200 -200 1" 
  590 t1 n3 200 -200 1 "-590 t1 n3 200 -200 1" 
  900 n3 t1 200 -200 1 "900 n3 t1 200 -200 1" 
  900 t1 n3 200 -200 1 "-900 t1 n3 200 -200 1" 
  0   n3 t1 200 200 1 "0 n3 t1 200 200 1" 
  100 n3 t1 200 200 1 "100 n3 t1 200 200 1" 
  100 t1 n3 200 200 1 "-100 t1 n3 200 200 1" 
  196 n3 t1 200 200 1 "196 n3 t1 200 200 1" 
  196 t1 n3 200 200 1 "-196 t1 n3 200 200 1" 
  280 n3 t1 200 200 1 "280 n3 t1 200 200 1" 
  280 t1 n3 200 200 1 "-280 t1 n3 200 200 1" 
  430 n3 t1 200 200 1 "430 n3 t1 200 200 1" 
  430 t1 n3 200 200 1 "-430 t1 n3 200 200 1" 
  590 n3 t1 200 200 1 "590 n3 t1 200 200 1" 
  590 t1 n3 200 200 1 "-590 t1 n3 200 200 1" 
  900 n3 t1 200 200 1 "900 n3 t1 200 200 1" 
  900 t1 n3 200 200 1 "-900 t1 n3 200 200 1" 
  0   n1 n2 -200 -200 2 "0 n1 n2 -200 -200 2" 
  100 n1 n2 -200 -200 2 "100 n1 n2 -200 -200 2" 
  100 n2 n1 -200 -200 2 "-100 n2 n1 -200 -200 2" 
  196 n1 n2 -200 -200 2 "196 n1 n2 -200 -200 2" 
  196 n2 n1 -200 -200 2 "-196 n2 n1 -200 -200 2" 
  280 n1 n2 -200 -200 2 "280 n1 n2 -200 -200 2" 
  280 n2 n1 -200 -200 2 "-280 n2 n1 -200 -200 2" 
  430 n1 n2 -200 -200 2 "430 n1 n2 -200 -200 2" 
  430 n2 n1 -200 -200 2 "-430 n2 n1 -200 -200 2" 
  590 n1 n2 -200 -200 2 "590 n1 n2 -200 -200 2" 
  590 n2 n1 -200 -200 2 "-590 n2 n1 -200 -200 2" 
  900 n1 n2 -200 -200 2 "900 n1 n2 -200 -200 2" 
  900 n2 n1 -200 -200 2 "-900 n2 n1 -200 -200 2" 
  0   n1 n2 -200 200 2 "0 n1 n2 -200 200 2" 
  100 n1 n2 -200 200 2 "100 n1 n2 -200 200 2" 
  100 n2 n1 -200 200 2 "-100 n2 n1 -200 200 2" 
  196 n1 n2 -200 200 2 "196 n1 n2 -200 200 2" 
  196 n2 n1 -200 200 2 "-196 n2 n1 -200 200 2" 
  280 n1 n2 -200 200 2 "280 n1 n2 -200 200 2" 
  280 n2 n1 -200 200 2 "-280 n2 n1 -200 200 2" 
  430 n1 n2 -200 200 2 "430 n1 n2 -200 200 2" 
  430 n2 n1 -200 200 2 "-430 n2 n1 -200 200 2" 
  590 n1 n2 -200 200 2 "590 n1 n2 -200 200 2" 
  590 n2 n1 -200 200 2 "-590 n2 n1 -200 200 2" 
  900 n1 n2 -200 200 2 "900 n1 n2 -200 200 2" 
  900 n2 n1 -200 200 2 "-900 n2 n1 -200 200 2" 
  0   n1 n2 200 -200 2 "0 n1 n2 200 -200 2" 
  100 n1 n2 200 -200 2 "100 n1 n2 200 -200 2" 
  100 n2 n1 200 -200 2 "-100 n2 n1 200 -200 2" 
  196 n1 n2 200 -200 2 "196 n1 n2 200 -200 2" 
  196 n2 n1 200 -200 2 "-196 n2 n1 200 -200 2" 
  280 n1 n2 200 -200 2 "280 n1 n2 200 -200 2" 
  280 n2 n1 200 -200 2 "-280 n2 n1 200 -200 2" 
  430 n1 n2 200 -200 2 "430 n1 n2 200 -200 2" 
  430 n2 n1 200 -200 2 "-430 n2 n1 200 -200 2" 
  590 n1 n2 200 -200 2 "590 n1 n2 200 -200 2" 
  590 n2 n1 200 -200 2 "-590 n2 n1 200 -200 2" 
  900 n1 n2 200 -200 2 "900 n1 n2 200 -200 2" 
  900 n2 n1 200 -200 2 "-900 n2 n1 200 -200 2" 
  0   n1 n2 200 200 2 "0 n1 n2 200 200 2" 
  100 n1 n2 200 200 2 "100 n1 n2 200 200 2" 
  100 n2 n1 200 200 2 "-100 n2 n1 200 200 2" 
  196 n1 n2 200 200 2 "196 n1 n2 200 200 2" 
  196 n2 n1 200 200 2 "-196 n2 n1 200 200 2" 
  280 n1 n2 200 200 2 "280 n1 n2 200 200 2" 
  280 n2 n1 200 200 2 "-280 n2 n1 200 200 2" 
  430 n1 n2 200 200 2 "430 n1 n2 200 200 2" 
  430 n2 n1 200 200 2 "-430 n2 n1 200 200 2" 
  590 n1 n2 200 200 2 "590 n1 n2 200 200 2" 
  590 n2 n1 200 200 2 "-590 n2 n1 200 200 2" 
  900 n1 n2 200 200 2 "900 n1 n2 200 200 2" 
  900 n2 n1 200 200 2 "-900 n2 n1 200 200 2" 
  0   n1 n3 -200 -200 2 "0 n1 n3 -200 -200 2" 
  100 n1 n3 -200 -200 2 "100 n1 n3 -200 -200 2" 
  100 n3 n1 -200 -200 2 "-100 n3 n1 -200 -200 2" 
  196 n1 n3 -200 -200 2 "196 n1 n3 -200 -200 2" 
  196 n3 n1 -200 -200 2 "-196 n3 n1 -200 -200 2" 
  280 n1 n3 -200 -200 2 "280 n1 n3 -200 -200 2" 
  280 n3 n1 -200 -200 2 "-280 n3 n1 -200 -200 2" 
  430 n1 n3 -200 -200 2 "430 n1 n3 -200 -200 2" 
  430 n3 n1 -200 -200 2 "-430 n3 n1 -200 -200 2" 
  590 n1 n3 -200 -200 2 "590 n1 n3 -200 -200 2" 
  590 n3 n1 -200 -200 2 "-590 n3 n1 -200 -200 2" 
  900 n1 n3 -200 -200 2 "900 n1 n3 -200 -200 2" 
  900 n3 n1 -200 -200 2 "-900 n3 n1 -200 -200 2" 
  0   n1 n3 -200 200 2 "0 n1 n3 -200 200 2" 
  100 n1 n3 -200 200 2 "100 n1 n3 -200 200 2" 
  100 n3 n1 -200 200 2 "-100 n3 n1 -200 200 2" 
  196 n1 n3 -200 200 2 "196 n1 n3 -200 200 2" 
  196 n3 n1 -200 200 2 "-196 n3 n1 -200 200 2" 
  280 n1 n3 -200 200 2 "280 n1 n3 -200 200 2" 
  280 n3 n1 -200 200 2 "-280 n3 n1 -200 200 2" 
  430 n1 n3 -200 200 2 "430 n1 n3 -200 200 2" 
  430 n3 n1 -200 200 2 "-430 n3 n1 -200 200 2" 
  590 n1 n3 -200 200 2 "590 n1 n3 -200 200 2" 
  590 n3 n1 -200 200 2 "-590 n3 n1 -200 200 2" 
  900 n1 n3 -200 200 2 "900 n1 n3 -200 200 2" 
  900 n3 n1 -200 200 2 "-900 n3 n1 -200 200 2" 
  0   n1 n3 200 -200 2 "0 n1 n3 200 -200 2" 
  100 n1 n3 200 -200 2 "100 n1 n3 200 -200 2" 
  100 n3 n1 200 -200 2 "-100 n3 n1 200 -200 2" 
  196 n1 n3 200 -200 2 "196 n1 n3 200 -200 2" 
  196 n3 n1 200 -200 2 "-196 n3 n1 200 -200 2" 
  280 n1 n3 200 -200 2 "280 n1 n3 200 -200 2" 
  280 n3 n1 200 -200 2 "-280 n3 n1 200 -200 2" 
  430 n1 n3 200 -200 2 "430 n1 n3 200 -200 2" 
  430 n3 n1 200 -200 2 "-430 n3 n1 200 -200 2" 
  590 n1 n3 200 -200 2 "590 n1 n3 200 -200 2" 
  590 n3 n1 200 -200 2 "-590 n3 n1 200 -200 2" 
  900 n1 n3 200 -200 2 "900 n1 n3 200 -200 2" 
  900 n3 n1 200 -200 2 "-900 n3 n1 200 -200 2" 
  0   n1 n3 200 200 2 "0 n1 n3 200 200 2" 
  100 n1 n3 200 200 2 "100 n1 n3 200 200 2" 
  100 n3 n1 200 200 2 "-100 n3 n1 200 200 2" 
  196 n1 n3 200 200 2 "196 n1 n3 200 200 2" 
  196 n3 n1 200 200 2 "-196 n3 n1 200 200 2" 
  280 n1 n3 200 200 2 "280 n1 n3 200 200 2" 
  280 n3 n1 200 200 2 "-280 n3 n1 200 200 2" 
  430 n1 n3 200 200 2 "430 n1 n3 200 200 2" 
  430 n3 n1 200 200 2 "-430 n3 n1 200 200 2" 
  590 n1 n3 200 200 2 "590 n1 n3 200 200 2" 
  590 n3 n1 200 200 2 "-590 n3 n1 200 200 2" 
  900 n1 n3 200 200 2 "900 n1 n3 200 200 2" 
  900 n3 n1 200 200 2 "-900 n3 n1 200 200 2" 
  0   n2 n3 -200 -200 2 "0 n2 n3 -200 -200 2" 
  100 n2 n3 -200 -200 2 "100 n2 n3 -200 -200 2" 
  100 n3 n2 -200 -200 2 "-100 n3 n2 -200 -200 2" 
  196 n2 n3 -200 -200 2 "196 n2 n3 -200 -200 2" 
  196 n3 n2 -200 -200 2 "-196 n3 n2 -200 -200 2" 
  280 n2 n3 -200 -200 2 "280 n2 n3 -200 -200 2" 
  280 n3 n2 -200 -200 2 "-280 n3 n2 -200 -200 2" 
  430 n2 n3 -200 -200 2 "430 n2 n3 -200 -200 2" 
  430 n3 n2 -200 -200 2 "-430 n3 n2 -200 -200 2" 
  590 n2 n3 -200 -200 2 "590 n2 n3 -200 -200 2" 
  590 n3 n2 -200 -200 2 "-590 n3 n2 -200 -200 2" 
  900 n2 n3 -200 -200 2 "900 n2 n3 -200 -200 2" 
  900 n3 n2 -200 -200 2 "-900 n3 n2 -200 -200 2" 
  0   n2 n3 -200 200 2 "0 n2 n3 -200 200 2" 
  100 n2 n3 -200 200 2 "100 n2 n3 -200 200 2" 
  100 n3 n2 -200 200 2 "-100 n3 n2 -200 200 2" 
  196 n2 n3 -200 200 2 "196 n2 n3 -200 200 2" 
  196 n3 n2 -200 200 2 "-196 n3 n2 -200 200 2" 
  280 n2 n3 -200 200 2 "280 n2 n3 -200 200 2" 
  280 n3 n2 -200 200 2 "-280 n3 n2 -200 200 2" 
  430 n2 n3 -200 200 2 "430 n2 n3 -200 200 2" 
  430 n3 n2 -200 200 2 "-430 n3 n2 -200 200 2" 
  590 n2 n3 -200 200 2 "590 n2 n3 -200 200 2" 
  590 n3 n2 -200 200 2 "-590 n3 n2 -200 200 2" 
  900 n2 n3 -200 200 2 "900 n2 n3 -200 200 2" 
  900 n3 n2 -200 200 2 "-900 n3 n2 -200 200 2" 
  0   n2 n3 200 -200 2 "0 n2 n3 200 -200 2" 
  100 n2 n3 200 -200 2 "100 n2 n3 200 -200 2" 
  100 n3 n2 200 -200 2 "-100 n3 n2 200 -200 2" 
  196 n2 n3 200 -200 2 "196 n2 n3 200 -200 2" 
  196 n3 n2 200 -200 2 "-196 n3 n2 200 -200 2" 
  280 n2 n3 200 -200 2 "280 n2 n3 200 -200 2" 
  280 n3 n2 200 -200 2 "-280 n3 n2 200 -200 2" 
  430 n2 n3 200 -200 2 "430 n2 n3 200 -200 2" 
  430 n3 n2 200 -200 2 "-430 n3 n2 200 -200 2" 
  590 n2 n3 200 -200 2 "590 n2 n3 200 -200 2" 
  590 n3 n2 200 -200 2 "-590 n3 n2 200 -200 2" 
  900 n2 n3 200 -200 2 "900 n2 n3 200 -200 2" 
  900 n3 n2 200 -200 2 "-900 n3 n2 200 -200 2" 
  0   n2 n3 200 200 2 "0 n2 n3 200 200 2" 
  100 n2 n3 200 200 2 "100 n2 n3 200 200 2" 
  100 n3 n2 200 200 2 "-100 n3 n2 200 200 2" 
  196 n2 n3 200 200 2 "196 n2 n3 200 200 2" 
  196 n3 n2 200 200 2 "-196 n3 n2 200 200 2" 
  280 n2 n3 200 200 2 "280 n2 n3 200 200 2" 
  280 n3 n2 200 200 2 "-280 n3 n2 200 200 2" 
  430 n2 n3 200 200 2 "430 n2 n3 200 200 2" 
  430 n3 n2 200 200 2 "-430 n3 n2 200 200 2" 
  590 n2 n3 200 200 2 "590 n2 n3 200 200 2" 
  590 n3 n2 200 200 2 "-590 n3 n2 200 200 2" 
  900 n2 n3 200 200 2 "900 n2 n3 200 200 2" 
  900 n3 n2 200 200 2 "-900 n3 n2 200 200 2" 

task ab
  table abtable            # use the table abtable
  keys b n space           # keys to be used, x and m are chosen for a reason
  show bitmap fix         # draw fix point and 4 boxes
  show bitmap box -200 0    
  show bitmap box 200 0    
  show bitmap box 0 200 
  show bitmap box 0 -200
  delay 500                # and wait for 500 ms
  readkey 1 120000         # wait up to 2 minutes for any key to start task
  delay 1000
  show bitmap @2 @4 0      # show stimulus 1 (left or right)
  delay 50                 # presentation time of stimulus 1
  show  bitmap mask @4 0   # show mask over stimulus 1
  delay @1                 # delay between stimuli (which is shorter than SOA)
  show  bitmap @3 0 @5     # show stimlus 2 (top or bottom)
  delay 50                 # presentation time of stimulus 2
  show  bitmap mask 0 @5   # show mask over stimulus 1
  readkey @6 5000          # wait for response up to 5s
  clear 1                  # erase fixpoint
  ## now there are four feedback types --------------------
  if STATUS == CORRECT & @6 == 1 # correct and present
    show bitmap correct_l
    delay 500              
    clear -1               
  fi
  if STATUS == CORRECT & @6 == 2 # correct and not present
    show bitmap correct_no_l  
    delay 500              
    clear -1               
  fi                       
  if STATUS != CORRECT & @6 == 1 # not correct and present
    show bitmap wrong_l
    delay 500              
    clear -1               
  fi
  if STATUS != CORRECT & @6 == 2 # correct and not present
    show bitmap wrong_no_l  
    delay 500              
    clear -1               
  fi                       
  ## feedback done-----------------------------------------
  delay 500                # wait 500 ms
  clear 2 3 4 5 6 7 8 9    # clear all remaining stimuli
  save  @7 RT STATUS       # save trial information to disk 

block abblock
  pager info1 info2 info3
  tasklist 
    ab 100
  end
  ## times are 0 100 196 280 430 590 900
  feedback
    set &i0correct count c6 ; select c1 == 0 && c8 == 1
    set &i0total   count c6 ; select c1 == 0
    set &i0perc expression &i0correct / &i0total * 100
    #
    set &i100correct count c6 ; select c1 == 0 && c8 == 1
    set &i100total   count c6 ; select c1 == 0
    set &i100perc expression &i100correct / &i100total * 100
    #
    set &i196correct count c6 ; select c1 == 196 && c8 == 1
    set &i196total   count c6 ; select c1 == 196
    set &i196perc expression &i196correct / &i196total * 100
    #
    set &i280correct count c6 ; select c1 == 280 && c8 == 1
    set &i280total   count c6 ; select c1 == 280
    set &i280perc expression &i280correct / &i280total * 100
    #
    set &i430correct count c6 ; select c1 == 430 && c8 == 1
    set &i430total   count c6 ; select c1 == 430
    set &i430perc expression &i430correct / &i430total * 100
    #
    set &i590correct count c6 ; select c1 == 590 && c8 == 1
    set &i590total   count c6 ; select c1 == 590
    set &i590perc expression &i590correct / &i590total * 100
    #
    set &i900correct count c6 ; select c1 == 900 && c8 == 1
    set &i900total   count c6 ; select c1 == 900
    set &i900perc expression &i900correct / &i900total * 100
    # 
    text 0 -300 "Percentage correct target detections depending on interval:"
    text 0 -200 &i0perc   ; prefix "Interval   0:" ; postfix "%"
    text 0 -150 &i100perc ; prefix "Interval 100:" ; postfix "%"
    text 0 -50 &i196perc ; prefix "Interval 196:" ; postfix "%"    
    text 0  0 &i280perc ; prefix "Interval 280:" ; postfix "%"
    text 0  50  &i430perc ; prefix "Interval 430:" ; postfix "%"
    text 0  100 &i590perc ; prefix "Interval 590:" ; postfix "%"    
    text 0  150 &i900perc ; prefix "Interval 900:" ; postfix "%"
    text 0  250 "Press space bar"
  end

Download

If you have a PsyToolkit account, you can upload the zipfile directly to your PsyToolkit account. Watch a video on how to do that. If you want to upload the zipfile into your PsyToolkit account, make sure the file is not automatically uncompressed (some browsers, especially Mac Safari, by default uncompress zip files). Read here how to easily deal with this.

Further reading

  • Duncan, J., Ward, R., & Shapiro, K. (1994). Direct measurement of attentional dwell time in human vision. Nature, 396, 313-315.

  • 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, 849–860.