Test description
Predetermined sequences of numbers (as shown in the table below) are presented visually using images of blocks. On screen, each sequence of numbers is presented by making the corresponding boxes ‘glow’ yellow in turn. During the presentation of a sequence, each block glows for 1 second. Between numbers in a sequence, there is an interval of 1 second, during which the boxes are not glowing.
Immediately after each sequence has been presented, a text prompt appears on screen inviting the subject to start reproducing the sequence; they do this by clicking on the blocks in turn, using the mouse. As the subject clicks on each block, the clicked block glows yellow as before; it then remains yellow until the next block is clicked. Clicks in the black areas between blocks are not registered. Responses are irreversible – after clicking a block, the subject may not cancel or change their mind.
The response is completed when the respondent has clicked the required number of blocks. E.g. at level 4, the response is complete when 4 blocks have been clicked (a 5th click is therefore not registered); after the 4th click, the intermediate screen is presented.
The intermediate screen appears after every item except for the last. On the intermediate screen, subjects click a button to choose between two courses of action: either continue the test, or come back later.
Depiction of blocks
Arrangement of numbered blocks (Note: the numbers on the blocks serve to establish the different sequences. The numbers do not appear on the blocks for participants in the test)
Appearance of blocks on screen, with one block highlighted:
Test items
The test items are divided into six levels of difficulty, numbered 4 to 9. The number of the level represents the length of each sequence at that level. There are two items (sequences) at each level. The items and their levels are tabulated below:
|
Level |
NEW item number |
Sequence |
|
4 |
1 |
3 5 7 1 |
|
2 |
5 2 6 4 |
|
|
5 |
3 |
8 1 5 3 6 |
|
4 |
6 4 5 2 9 |
|
|
6 |
5 |
4 1 6 7 8 2 |
|
6 |
7 9 2 5 1 3 |
|
|
7 |
7 |
7 1 9 3 4 6 2 |
|
8 |
2 6 8 1 4 9 5 |
|
|
8 |
9 |
5 9 3 7 2 1 8 4 |
|
10 |
7 6 9 3 1 5 4 8 |
|
|
9 |
11 |
7 5 2 8 6 4 1 9 3 |
|
12 |
5 8 6 2 9 1 4 3 7 |
Test rules
- No branching rules.
- Discontinue rule: if both trials at a given level are incorrect, discontinue the test.
- Present a come-back later button on the intermediate screen after every item, except after discontinuing or ending the test.
- No special timeout rules apply.
- As usual, subjects are prevented from using the browser’s ‘back’ button to try items repeatedly.
- Responses are recorded in the form of a text string, containing the sequence of clicked block numbers.
- Each item scores 1 if answered correctly, 0 if not.
- The total test score is simply the sum of the item scores.
- The practice item (in the tutorial) is not scored.