User`s guide

E-Prime User’s Guide
Chapter 2: Using E-Studio
Page 12
2.2 Stage 1: Conceptualize and Implement
the Core Experimental Procedure
The goal of this stage is to get the basic procedure implemented to the point where the
experiment presents at least two different instances of the trial procedure. Be clear on the trial
procedure and what data are to be collected. We will first give an overview of the steps and then
give specific instructions for performing the steps. We present the graphical objects from E-Prime
to help associate the experimental specification with the visual interface in E-Prime.
We recommend reading through the next few pages to conceptualize the relationship of the
experimental steps and the E-Prime implementation without trying to do it on the computer.
First conceptualize how to go from an experimental idea to a computer exercise. Then we will go
back over the steps and show how to implement each stage. Note, in this text, we will include
images from E-Prime to show the relationship between experimental concepts and the E-Prime
objects and interface. Wait until this chapter’s section on Performing Stage 1 (section 2.3) to
actually implement the experiment.
Stage 1: Conceptualize and implement the core experimental procedure
Provide an operational specification of the base procedure
Create a folder for the experiment and load E-Studio
Specify the core experimental design, independent variables, stimuli, and expected responses
Specify the core experimental procedure
Set the non-default and varying properties of the Trial events
Specify what data will be logged for analysis
Run and verify the core experiment
Verify the data logging of the core experiment
2.2.1 Step 1.1: Provide an operational specification of
the base experiment
Operationally identify the experiment that you are trying to develop. What is being manipulated?
What is the expected outcome? State clearly the expected effect the independent variables might
have on the dependent variables. For example, in a lexical decision experiment, the
experimenter might present text strings that are either words or non-words, and record the
reaction time for the subject to categorize the stimulus as a word or a non-word. The question
might be whether it is faster to recognize a string of letters as a word or a non-word. It is useful to
write a draft of the abstract for the experiment being implemented, particularly detailing the
procedure. For the lexical decision experiment this might be:
The experiment will measure the time to make a lexical decision. The independent
variable is whether a letter string is a word or a non-word. The subject will be
presented with a fixation (+) displayed in the center of the screen for one second.
Then a probe display will present a letter string stimulus in the center of the screen
for up to 2 seconds. The stimulus display will terminate when the subject responds.
Subjects are to respond as quickly as possible as to whether the stimulus was a word
or a non-word by pressing the “1” or “2” key respectively. The dependent measures
are the response (i.e., key pressed), response time, and response accuracy of the
probe display. The stimuli will be words and non-words, presented in random order
in black text on a white background.
In Stage 1, we will implement the above procedure. In Stage 2, we will elaborate both the
description and the experiment.