This tutorial will walk you through creation of a full lexical decision task experiment (Meyer & Schvaneveldt, 1971) [1]. This example will be based on Experiment 1, where word pairs are presented with a limited time period to respond. The task requires participants to identify whether each word pair contains a non-word. At the end of each trial, participants are given feedback as to the correctness of their response. A timeout (no response within the given time) also equates to incorrect. Word pairs are associated with one of the following levels:
Tip: Throughout the tutorial there will be links to other documentation to explain concepts in detail. If you follow a link you can return to this tutorial by hitting the back button in your browser. Alternatively, you can right-click a link and open it in a new tab.
At the end of this tutorial you will have covered the following concepts:
Simple one-factor, three-level experiment using randomly selected stimuli.
Lexical decision task
and choose New
as the creation option.Stimuli
tab in the study tab bar.Create new set...
from the Choose stimulus set...
dropdown menu and name it Stimuli
.Components
in the stimulus set tree and add a new group called word pairs
with the component group type Discrete
and the component type Text
.word pairs
group by clicking on its name in the table or in the stimulus set tree.Create a CSV file containing your word pairs, and their associated factors and levels then import the CSV file. For convenience, you can download one I prepared earlier. The CSV file should look like this (Figure 1).
Study
tab in the study tab bar. Notice the factors and levels from our stimuli CSV file have automatically populated the factors table.Study sequence
by clicking on it in the study tree.Trial block
, choosing New
as the creation option and naming it Trial block
.Trial block
by clicking on its name in the table or in the study tree.Trials
, choosing New
as the creation option and naming it Trials
.
Trials
by clicking on its name in the table or in the study tree to arrive at the trials timeline.
Trials
by clicking on it in the study tree.Fixation
, choosing New
and naming it fixation
.fixation
item in the trials timeline to enter edit mode, set the Timeout (ms)
to 250 and set the fixation Type
to Cross (vertical)
.New
Interstimulus interval
called ISI
.ISI
and set the Start time (ms)
to 250 and Timeout (ms)
to 200.Stimulus component
and choosing word pairs
(this is the stimulus component we created earlier).word pairs
and set the Start time (ms)
to 450 and Timeout (ms)
to 1000.Response - keyboard
, choosing New
and naming it keys
.keys
and add the following using the Add key button:
Key
: f, Value
: pair only contains real wordsKey
: j, Value
: pair contains a non-wordSet Start time (ms)
to 450 and Timeout (ms)
to 1000.
Hit Save in the bottom right corner when you've finished.
Feedback
, choosing New
and naming it feedback
.feedback
and set the Timeout (ms)
to 250.We have now completed our trials timeline and it should look something like this (Figure 2).
Screen
in the trials tab bar.fixation
to the screen by hovering the mouse over the top of the grid and selecting the cell and then selecting fixation
from the Insert item list.word pairs
to the screen using the same method you used to add fixation
in step 2.feedback
to the screen using the same method you used to add fixation
in step 2.We have now finished building our trials screen. You can preview your work so far by clicking Preview study at the far right-hand end of the study tab bar.
Logic
in the trials tab bar.We have now finished building our trials logic, and with that, our experiment design is complete.
Although our experiment design is complete, it's not very friendly, so let's fix that.
Trial block
using the study tree and add new instructions, name it Instructions
and choose New
as the creation option.Instructions
to the top position in the trial block table to make it appear before Trials
.Add some introductory text (Figure 5).
Note: we could have created Instructions
in the study sequence above Trial block
but bundling Instructions
within a trial block provides the following advantages:
Response - keyboard
, New
as the creation option and name it key
.key
and add a new key. Press the Space bar to add the space key, set the value to anything you like (e.g. next
), then hit Add to add the key and then hit Save to exit edit mode.Study sequence
.Instructions
, select Copy
as the creation option, select Instructions
(the instructions we created in earlier in Trial block
) and name it Thankyou message
.Thankyou message
and change the text to a lovely thankyou message and change the space bar text to something like Press the space bar to exit
. Note: The last screen in your study must include a buttons response or a keyboard response to end the study. Set the response Event
to Go to next study item or trial
.You now have a fully functional experiment with random stimulus selection and per-trial participant feedback. Hit Preview study and try it out! To activate the study and allow participants to take part, hit the Distribution
tab in the study tab bar. To download results, hit the Results
tab in the study tab bar.