Introduction

Ian Deary is a famous professor in psychology, in particular known for his work in differential psychology and general intelligence. Together with members of his Edingburgh (Scotland) research group, he published an article about a four-choice response task.

Given that we know that response times correlate with general intelligence, it is useful to have an agreed standard procedure, and the Deary-Liewald task provides this (in a similar way as the Jensen task, Jensen, 2006).

About this implementation

  • The task follows the paper by Deary and colleagues (2011) as closely as possible.

If you have a German or French style keyboard, it makes sense to use different keys! Look at the lesson about simple and choice reaction time tasks, where this task has been modified to use the x,c,b, and n keys (which works on English/US/German/French-style keyboards). Click here to go to that lesson.

Run the demo

In this example, you will do a simple response time task and a choice response time task (for an explanation, read this in the PsyToolkit lessons).

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

blockname

2

training (1=training, 0=real data collection)

3

number of choices (1 in simple block, 4 in choice block)

4

time between response and next trial (between 1 and 3 seconds)

5

the x-coordinate of the target stimulus

6

the response time (ms)

7

status (1=correct, 2=error, 3=too slow)

PsyToolkit code

Click to expand the PsyToolkit script code (part of zip file below) 
options
  bitmapdir stimuli
  set &dummy 0
  set &maxResponseTime 3000
  set &minInterval 1000
  set &maxInterval 3000  

fonts
  arial 18
  
bitmaps
  instruction_simple_task
  instruction_choice_task1
  instruction_choice_task2
  instruction_choice_task3
  readytraining
  readyreal
  thankyou
  title
  too_slow
  wrong_key
  reminder
  box_empty
  box_cross

table dl_choice
  4 -150 1
  4 -50  2
  4  50  3
  4 150  4

task dl_task_simple
  keys space
  set $num_choices 1
  show background 0 0 100
  show bitmap box_empty
  set $randomdelay random &minInterval &maxInterval
  delay $randomdelay
  show bitmap box_cross
  readkey 1 &maxResponseTime
  clear 3
  save BLOCKNAME &training $num_choices $randomdelay &dummy RT STATUS

task dl_task_choice
  table dl_choice
  keys z x comma period
  show background 0 0 100
  show bitmap box_empty -150 0
  show bitmap box_empty -50 0
  show bitmap box_empty  50 0
  show bitmap box_empty  150 0
  set $randomdelay random &minInterval &maxInterval
  delay $randomdelay
  show bitmap box_cross  @2 0
  readkey @3 &maxResponseTime
  clear 6
  if &training == 1 && STATUS != CORRECT ## only during training give feedback
    if STATUS == WRONG
      show bitmap wrong_key
    fi
    if STATUS == TIMEOUT
      show bitmap too_slow
    fi
    delay 700
    clear -1
    show bitmap reminder
    delay 2000
    clear -1
  fi
  save BLOCKNAME &training @1 $randomdelay @2 RT STATUS

######################################################################
## blocks start here

block dlsimple_training
  set &training 1
  message title
  message instruction_simple_task
  message readytraining
  tasklist
    dl_task_simple 8
  end
  delay 1000

block dlsimple_real
  set &training 0
  message readyreal
  tasklist
    dl_task_simple 20
  end
  delay 1000

block dlchoice_training
  set &training 1
  message instruction_choice_task1
  message instruction_choice_task2
  message instruction_choice_task3  
  message readytraining
  tasklist
    dl_task_choice 8 no_repeat
  end
  delay 1000
  
block dlchoice_real
  set &training 0
  message readyreal
  tasklist
    dl_task_choice 40 no_repeat
  end
  feedback
    set &simpleRt mean c6 ; select c2 == 0 && c7 == 1 && c3 == 1
    set &choiceRt mean c6 ; select c2 == 0 && c7 == 1 && c3 == 4
    text 0 -200 "Your response speed in correct trials, training not included:"
    text 0 -100 &simpleRt ; prefix "In simple task:" ; postfix "ms"
    text 0    0 &choiceRt ; prefix "In choice task:" ; postfix "ms"
    text 0 100 "Write numbers down, and press space bar to continue"
  end
  
message thankyou

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

  • Deary, Liewald & Nissan (2011). Behaviour Research Methods, 43, 258-268.

  • Jensen, A. R. (2006). Clocking the mind: mental chronometry and individual differences. Amsterdam, The Netherlands: Elsevier.