If you wish to try one of our core tasks, please click on the task for an interactive demo.

• Simple Reaction Time
• Digit Vigilance
• Choice Reaction Time
• Numeric Working Memory
• Spatial Working Memory
• Word Presentation / Word Recognition
• Picture Presentation / Picture Recognition

The CDR tasks that are available:

• Immediate Word Recall
  A list of 15 words is presented on the screen at the rate of 1 every 2 seconds for the participant to remember. The participant is then given 1 minute to recall as many of the words as possible.
• Picture Presentation
  A series of 20 pictures is presented on the screen at the rate of 1 every 3 seconds for the participant to remember.
• Simple Reaction Time
  The participant is instructed to press the 'YES' response button as quickly as possible every time the word 'YES' is presented on the screen. Fifty stimuli are presented with a varying inter-stimulus interval.
• Digit Vigilance
  A target digit is randomly selected and constantly displayed to the right of the screen. A series of digits is then presented in the centre of the screen at the rate of 150 per minute and the participant is required to press the 'YES' button as quickly as possible every time the digit in the series matches the target digit. There are 45 targets in the series. The task lasts for 3 minutes.
• Choice Reaction Time
  Either the word 'NO' or the word 'YES' is presented on the screen and the participant is instructed to press the corresponding button as quickly as possible. There are 50 trials for which each stimulus word is chosen randomly with equal probability and there is a varying inter-stimulus interval.
• Spatial Working Memory
  A picture of a house is presented on the screen with 4 of its 9 windows lit. The participant has to memorise the position of the lit windows. For each of the 36 subsequent presentations of the house, the participant is required to decide whether or not the 1 window that is lit was also lit in the original presentation. The participant responds by pressing the 'YES' or 'NO' buttons as appropriate, as quickly as possible.
• Numeric Working Memory
  A series of 5 digits is presented for the participant to hold in memory. This is followed by a series of 30 probe digits for each of which the participant has to decide whether or not it is in the original series and press the 'YES' or 'NO' response button as appropriate, as quickly as possible.
• Delayed Word Recall
  The participant is again given 1 minute to recall as many of the words as possible from the original word presentation.
• Word Recognition
  The original words plus 15 distracter words are presented one at a time in a randomised order. For each word the participant is required to indicate whether or not the participant recognises it as being from the original list of words by pressing the 'YES' or 'NO' button as appropriate, as quickly as possible.
• Picture Recognition
  The original pictures plus 20 distracter pictures are presented one at a time in a randomised order. For each picture the participant has to indicate whether or not the participant recognises it as being from the original series by pressing the 'YES' or 'NO' button as appropriate, as quickly as possible.
• Bond-Lader Visual Analogue Scale of Mood and Alertness
  This questionnaire of 16 analogue scales derives 3 factors that assess change in Self-rated Alertness, Self-rated Calmness and Self-rated Contentment. It has proven sensitivity to a wide range of compounds. A computerised version of this test is employed, with the participant using the computer mouse.
• Trail Making test
  The test is composed of two parts, Parts A and B. Part A consists of 25 numbers which are randomly arranged on a sheet of white paper. participants are required to sequentially connect the numbers via drawn lines as quickly as possible until they reach the number 25. Part B consists of 13 numbers (i.e., 1 � 13) and 12 letters (i.e., A � L) which are randomly arranged on a sheet of white paper. Individuals are required to start with the number one and sequentially alternate between numbers and letters of the alphabet via drawn lines as quickly as possible until they reach the last number (i.e., 13). Both parts of the task are timed.
• Rapid Visual Information Processing (RVIP)
  A series of digits is presented on the screen at the rate of 100 per minute. The participant has to detect targets consisting of consecutive sequences of either 3 odd digits or 3 even digits, and to report them by pressing the 'YES' button as quickly as possible. There are 32 targets. The task lasts for 4 minutes.
• Tracking
  The participant uses a joystick to track a randomly moving target on the screen for 1 minute. The distance off-target per second is recorded.
• Logical Reasoning
  A statement is presented on the screen referring to a relationship between the pair of letters that followed it. The participant is required to press the 'YES' button as quickly as possible if the statement correctly describes the letter pair, or the 'NO' button if it does not.
• Digit Symbol Substitution Test (DSST)
  In this classic pen and paper test, the participant is given 90 seconds to complete as many substitutions of symbols as possible according to a code provided at the top of the sheet.
• Critical Flicker Fusion
  The participant performs a series of trials in which a pair of flickering lights are viewed. In the first three trials the frequency of flicker increases until imperceptible, at which point the participant has to press a button on the response box. In the second 3 trials the frequency of flicker decreases until perceptible, at which point the participant has to press a button on the response box. A threshold frequency value, which the participant is able to perceive, is calculated. Using this threshold frequency value a further 20 trials are then administered, in which the participant decides, using the response box, which of the 2 lights are flickering, with frequency increasing or decreasing dependent on correct or incorrect responses. The final value is then used as the measure of flicker frequency, which the participant is able to perceive. Pupil size is controlled using a 3mm artificial pupil.
• Morse Tapping Task
  The participant is required to continuously tap a button as quickly as possible. The participant responds with one hand for a 30 second period and then responds for another 30 second period using the opposite hand. The order in which the left and right hands are used is randomised.
• Postural Stability
  The ability to stand upright without moving is assessed using the CDR meter that is modelled on the Wright Ataxiameter (Wright, 1971). A cord from the meter is attached to the participant who is required to stand as still as possible with feet apart and eyes closed for 1 minute.
• The St. Mary's Sleep Questionnaire
  This self administered pen and paper questionnaire procedure has proven sensitivity to drug-induced alterations in self-rated sleep quality.
• Controlled Oral Word Association (COWAT)
  This task measures aspects of verbal fluency and working memory. The participant is given one minute to list as many words as they can which begin with a given letter. Validated sets of letters include: F, A, S; C, F, L & P, R, W. The participant completes the task on paper and the CDR computer controls the timing. This task requires one-to-one test administration.