Visual Lexical Decision Experiment with Visual Prime (template)
Please read the generic documentation for context and scope.
The participant first sees a fixation cross, then a prime is presented, followed by the test stimulus. Particpants are instructed to respond as quickly as possible to make the decision if both strings in the pair are words --or not--, using the keyboard.
- The prime is a string of letters and can be a real word or a nonword.
- The 'test stimulus' is a string of letters and can also be a real word or a nonword.
In this version, a trial consists of subsequently presenting two words or nonwords. The participant needs to make a swift decision whether the pair of presented sets of letters - the test stimuli - are both acutal words or not. Only in this last phase (the decision phase), as soon as the item is being presented, the participant can respond with the keyboard.
Crucial trial phases (sub trial phases):
- Fixation cross
- Visual Prime
- Lexical decision (decision phase)
Rubenstein, H., Garfield, L., & Millikan, J.A. (1970).
Homographic entries in the internal lexicon.
Journal of Verbal Learning and Verbal Behavior, 9, 487≠494.
The data of all (sub) trial phases are logged in the data, but the output data can be filtered after data collection in many ways. Please read the general primer on jsPsych's data if you are new to jsPsych data output.
Essential output for the 'true experimental' purpose in this template are:
- Reaction Time (RT) of the keyboard response in the decision phase
- Correctness of the keyboard response in the decision phase
The crucial trial/sub-trial phase (decision phase) output may look similar to this:
{
"rt": 368.0000000000073,
"stimulus": "<p class='stimulus'>crawse</p>",
"key_press": 76,
"condition": "NON_WORD",
"word": "crawse",
"prime": "piano",
"id": 2,
"trial_phase": "present_word",
"useful_data_flag": true,
"correct_response": 0,
"trial_type": "html-keyboard-response",
"trial_index": 25,
"time_elapsed": 44933,
"internal_node_id": "0.0-11.0-2.1",
"subject": "f9pdgg60",
"list": "my_one_and_only_list",
"correct": true,
"integer_correct": 1,
"key_chosen_ascii": 76,
"key_chosen_char": "L",
"yes_key": "A",
"no_key": "L"
},
//...| Variable name (key) | Description | Unit | Type | Comments | jsPsych default | Template default | Plugin name |
|---|---|---|---|---|---|---|---|
| "rt" | Reaction Time | ms. | float | Reaction time in milliseconds | yes | ||
| stimulus" | stimulus (html) | string/html | yes | ||||
| "key_press" | Keyboard response | string/object? | https://en.wikipedia.org/wiki/ASCII | yes | html-keyboard-response | ||
| "condition" | Condition | string | See stimuli.js |
no | yes | ||
| "word" | Decision phase item | string/html | See stimuli.js, index.html |
no | yes | ||
| "prime" | Prime phase item | string/html | (...) | no | yes | ||
| "id" | ID/code | (...) | yes | ||||
| "trial_phase" | Trial phase | (...) | no | yes | |||
| "useful_data_flag" | Filter flag | boolean | no | yes | |||
| "expected_answer" | TODO change! | todo | Now (still) named "correct_response" | no | no/yes/willbe. | ||
| "trial_type" | What plugin was used | yes | "html-keyboard-response" | ||||
| "trial_index" | jsPsych index | yes | |||||
| "time_elapsed". | jsPsych time object | ms? | int (/float?) | For instance: 45062 | yes | ||
| "internal_node_id. | jsPsych node object | For instance:"0.0-11.0-1.4" | yes | ||||
| "subject" | Subject ID | For instance: "8oo722dq" | yes | ||||
| "list" | Stimulus list name. | string | For instance: "my_one_and_only_list" | no | yes | ||
| "correct" | Scoring result | Boolean | 'true or false' score of response | yes | |||
| "integer_correct" | Scoring result | integer | 1 or 0 for correct or incorrect | yes | |||
| "key_chosen_ascii" | For instance: 65 | no | yes | ||||
| "key_chosen_char" | For instance: "A" | no | yes | ||||
| "yes_key" | For instance: "A" | no | yes | ||||
| "no_key" | For instance: "L" | no | yes |
People affiliated with our lab can use the information from our lab webiste and expand the "Online experiments using jsPsych" section for details. Please follow this how-to.
In the file globals.js is a variable:
const ACCESS_KEY = '00000000-0000-0000-0000-000000000000';Before uploading your experimentto the UiL-OTS data server, you will need to change this to the access_key that you obtained when your experiment was approved. For elaborate info see globals.js.
- Open the file
stimuli.jsin your plain text editor. - There is a list, called LIST_1:
const LIST_1 = [ // stimuli and timeline variables
- This list can be adapted to your own needs, i.e, you can replace values, make the list longer (don't forget to increment the 'id' values for new items!).
- If you need to implement a more complex design, you should read the
stimuli.jsfile (and its comment sections) a little better. - For an example of a Latin square design, please have a look here.