User`s guide

E-Prime User’s Guide
Chapter 2: Using E-Studio
Page 18
Press the “1” or “2” key, the text string will disappear, and the experiment will go to the next trial.
Note, each experiment run begins by asking for the subject number and session number (not
shown in this example).
2.2.8 Step 1.8: Verify the data logging of the core
experiment
An experiment is only useful if the critical data are recorded for later analysis. Be clear about
what expectations to see as input data for the analysis. From the abstract:
The independent variable is whether a letter string is a word or non-word… The
dependent measures are the response (i.e., key pressed), response time, and
response accuracy of the probe display.
In this case, basically expect to see the two rows of the DesignList plus the dependent measures
(subject response, response time, and accuracy of the response) in the data file. Analyze the
data using E-DataAid. The trial described above might appear like the following:
Independent Variables (from DesignList) Dependent Variables (from run)
Condition Stimulus CorrectResponse Probe.RESP Probe.RT Probe.ACC
Word cat 1 1 586 1
NonWord jop 2 1 1224 0
For trial 1 of this run of the experiment, the independent variables (attributes of the DesignList)
were Condition=Word, Stimulus=Cat, and CorrectResponse=1. The dependent variables were
the response key (Probe.RESP=1), response time (Probe.RT=586), and response accuracy
(Probe.ACC=1, indicating a correct answer). For trial 2, the Condition=NonWord, Stimulus=Jop,
CorrectResponse=2, Probe.Resp=1 (which mismatches the expected response),
Probe.RT=1224, and Probe.ACC=0 (indicating an error). Note, the average of all the Probe.ACC
values will give the average accuracy (1 for correct, 0 for error).
Stage 1 Summary. In steps 1.1 through 1.7 we conceptualized, implemented, and verified the
data logging of the core experiment, limiting the design to two cells. It is important at this stage to
conceptualize each of the steps discussed, and to relate them to the experimental procedures.
Exercise: For experiment development, draw the figures expected to occur, as above. In
particular, specify the 1) abstract of the core experiment; 2) folder name for the experiment and
where to keep it; 3) DesignList of the conditions, stimuli, and correct responses; 4) core
experimental procedure including when stimuli are selected and the trial procedure, including a
sequence of displays and subject responses; 5) non-default properties of the trial events,
including the fixed and varying text displays and the properties for how to display the stimulus, its
duration and termination condition, and the correct response; 6) what dependent measures will
be logged for further analysis; 7) expected subject displays (i.e., draw them), when responses
are to be made, and if they clear the screen; and 8) independent and dependent variables that
are logged for the experiment.
2.3 Performing Stage 1: Implement the
Core Experimental Procedure
In this section we will go over the specifics of performing each of the Stage 1 operations. To
perform the Stage 1 operations, we recommend reading through each step below and actually