User`s guide

E-Prime User’s Guide
Chapter 1: Introduction
Page 8
the format of the WAV files (e.g., 11,025Hz, 8 Bit, Mono). Most video and audio cards offering
DirectX support are compatible with E-Prime. Other restrictions imposed by MEL Professional
are alleviated by E-Prime. Reaction times are no longer restricted to a maximum integer value of
32767ms, and experiments are no longer restricted to a maximum of three levels (i.e., Session,
Block, Trial). E-Prime allows for up to 10 levels in the experiment structure (e.g., Session, Block,
Trial, Sub-Trial, etc.), and users have the ability to rename experiment levels (e.g., Passage,
Paragraph, Sentence, etc.).
The goal of E-Prime is to simplify the process of computerized experiment generation, while
providing the power to perform tasks required by the research community. With a Windows-
based environment and an object-based language, E-Prime facilitates experiment generation for
programmers and non-programmers alike, while offering the most powerful and flexible tool
available.
1.8 E-Prime for PsyScope Users
- Contributed by Brian MacWhinney, Carnegie Mellon University
PsyScope users often ask how E-Prime differs from PsyScope. Having invested a large amount
of effort to learn Psyscope, users would like to minimize the effort needed to learn to use E-
Prime. The following section will outline the differences and similarities between PsyScope and
E-Prime. PsyScope users will find that there are a number of similarities between the two
systems.
In building E-Prime, we relied in many ways on the design of PsyScope. As a result, much of E-
Prime has a touch and feel that is reminiscent of PsyScope. For example, the E-Prime Procedure
object uses the timeline metaphor of the PsyScope Event Template window. Similarly, the E-
Prime List object looks much like a PsyScope List window. In designing E-Prime, we also tried to
preserve the ways in which PsyScope made the design of the experiment graphically clear. The
E-Prime Structure view expresses much of what the PsyScope interface expressed through
linked objects in the Design window. We also preserved much of PsyScope’s user interface in
terms of the general concepts of ports, events, and factors. For example, a PsyScope event and
an E-prime object are conceptually identical, since an event is an object in a graphic timeline for
the trial.
However, when one gets under the hood, the two products are entirely different. The most
obvious difference is that the current release of E-Prime runs only on Windows. For the
PsyScope user familiar with the Macintosh user interface, the idiosyncrasies of Windows can be
frustrating. It simply takes time to get used to new methods of handling the mouse, expanding
and contracting windows, and dragging objects.
The other major difference is that E-prime uses E-Basic as its underlying scripting language,
thereby fully replacing PsyScript. PsyScript was a powerful language, but users with little
programming background found it difficult to master some of its conventions. The documentation
for PsyScript was often incomplete or difficult to follow. E-Basic, like Visual Basic for Applications,
is extremely well documented and conceptually easier than PsyScript. More importantly, there
was a great potential in PsyScope to break the link between the graphical user interface (GUI)
and the script. In some cases, a script could not be edited again from the GUI after these links
were broken. E-Prime, on the other hand, allows the user to write small blocks of E-Basic script
for specific objects or actions. This means that the user can use the scripting language to make
targeted minor modifications without affecting the overall graphic interface.