Sessions 5-6

In this session, we will explore OpenSesame as an alternative to E-Prime, covering the structure of OpenSesame, a comparison between both tools, and how to create tasks like the Stroop and lexical decision tasks.

OpenSesame Overview

Key Features

  • OpenSesame is an open-source, Python-based tool for designing experiments.
  • It is free, cross-platform, and has a large online community.
  • E-Prime, in contrast, is a paid software that works only on Windows but has more support at CIMCYC.

OpenSesame Structure

While OpenSesame is different from E-Prime, there are some parallels in structure:

OpenSesame E-Prime
list loop
procedure sequence
slide sketchpad

Some other elements are more specific to OpenSesame, such as the logger and keyboard_response.

Task Examples

Stroop Task in OpenSesame

Objective: Name the color of the ink, not the word.

  • Congruent Example: green.
  • Incongruent Example:green.
  • Timing:
    • Fixation: 1000 ms
    • Stimulus: 2000 ms (or until response)

Lexical Decision Task in OpenSesame

In this task, participants must decide whether a displayed string is a real word or a non-word.

Trial Structure: - Fixation: 1000 ms - Probe: 2000 ms

You will define which elements are fixed (e.g., fixation cross) and which vary (e.g., words).

Fixed Properties: - Text always “+” - Foreground and background color

Varying Properties: - Word: real or non-word - Response keys

Conditionals in Python

Structure

Conditionals allow specific actions depending on whether certain conditions are met.

Basic Example:

if [correct] == 1:
  print('well done')
if [correct] == 1 and [response_time] < 1000:
  print('well done')
elif [correct] == 0:
  print('try again')

Comparing E-Prime and OpenSesame

  • In what scenarios would you choose OpenSesame over E-Prime for designing an experiment? How does the open-source nature of OpenSesame influence its usability and flexibility compared to E-Prime?
  • What are the main trade-offs between the two tools (e.g., coding flexibility in OpenSesame vs. graphical interface in E-Prime)? Reflect on how these might affect your experimental workflow.

OpenSesame Task Design

  • When designing the Stroop task in OpenSesame, how do congruent and incongruent trials affect participant reaction times? What cognitive processes are being measured, and how can the experiment be adjusted to explore these further?
  • In the lexical decision task (or any other experiment), what considerations should be made regarding the fixed and variable properties? How do these properties affect the accuracy and reaction times in the experiment?

Conditionals in Python

  • How does using conditionals in Python allow for more flexibility in your experiment? Reflect on a scenario where you could use complex conditionals to provide feedback based on multiple conditions (e.g., accuracy and response time).
  • Compare the use of conditionals in OpenSesame with those in E-Basic. What are the key differences in syntax and application, and how might they affect your approach to designing an experiment?

Debugging and Error Handling in OpenSesame

  • Why is the debug console in OpenSesame an important tool when developing an experiment? How can you use it to monitor variables like subject_parity and ensure your conditionals are working as expected?
  • What challenges could arise when setting up counterbalancing or feedback mechanisms in OpenSesame, and how would you address these issues through debugging?

Below, you can find the slides from this session: