Chatter.py - a simulated chatting environment


Contents of this document:
  1. Download section
  2. Media Section
  3. Guide for dummies: installing Chatter.py on windows
    1. What do you need to run this program?
    2. Install Python
    3. Install the Python Image Library
    4. Running the program
  4. User Manual
    1. Making a stimulus script
    2. Starting the experiment
    3. The experiment and the participant
    4. The output
  5. Problems and their solution
    1. Possible problem 1: You're not using Windows but Linux, Mac, ...
    2. Possible Problem 2 : The icon is not a snake.

Download section

Download the Chatter.py Starting-Pack - This zip-file contains the Chatter.py file and some example stimuli. This allows you to quickly start exploring the program.

Media Section

For your eyes only! These are links to some screenshots. These are the same as the ones mentioned below.

Screenshot 1   Screenshot 2   Screenshot 3   Screenshot 4   Screenshot 5

Guide for dummies: installing Chatter.py on windows

What do you need to run this program?

The program is actually a Python script that uses some components of the Python Image Library. Since Python scripts are not meant to be compiled, you will need three things to run the program:
  1. The file Chatter.py - Of course you will need the script itself. Download the Starting-Pack containing the file using the link above.
  2. Python
  3. The Python Image Library

Install Python

"Python is an interpreted, interactive, object-oriented programming language. It is often compared to Tcl, Perl, Scheme or Java."  More about Python can be found here.

To run chatter.py you need to install the Python interpreter on your machine. This is very easy.

Download the latest version of Python from this website. For installing Python on Windows you should download the version marked "(Windows binary -- does not include source)". After downloading the file, you only have to double click it to start the installation. During the installation it is recommended to confirm all the standard parameters suggested by the installation program.

Install the Python Image Library

"The Python Imaging Library (PIL) adds image processing capabilities to your Python interpreter. This library supports many file formats, and provides powerful image processing and graphics capabilities."

Chatter.py uses the PIL to be able to handle more than 30 graphic formats. Without this extension only two obscure formats would be supported.

Again, installing the PIL (for Windows) is very easy. Download the installer at the website. Be sure to download the latest windows-version of the program.

Important: Download a version that corresponds to your Python version. If you have installed Python 2.4.1 then you should download "Python Imaging Library 1.1.5 for Python 2.4". If the version of the PIL does not match your Python version, the PIL will not install itself.

After downloading the file you can start the installation by double clicking the program. Confirm all the standard settings during the installation.

Running the program

Showtime. After installing Python (and the PIL) you will notice that the icon for the file chatter.py has been changed to a little snake:     Python Icon
If this is the case, you are ready to go. If the icon has not changed to this lovely snake, click here for the solution.

You can now start the program by double clicking the file. Something like this should pop up (click on it for a bigger image):


User Manual

Making a stimulus script

To run an experiment on with chatter.py you need a file listing the sentences and pictures to be shown during the experiment. This can be a simple *.txt file in which each file should be formatted like this one:
the pirate eats an apple/picture1.bmp/picture2.bmp/this is my stimulus

This line contains 4 obligatory parts divided by a slash (/):
  1. The sentence the computer that the computer will show to the participant. This is the prime sentence.
  2. The name of a picture that the computer should show to the participant while presenting the prime sentence. Place the picture in the same folder as chatter.py.
  3. The name of a picture the participant should describe. Placement of the picture: idem.
  4. Some comment. Can be ommited. But in this case the third slash should be appended (e.g. the pirate eats an apple/picture1.bmp/picture2.bmp/)
Click here to see a short example stimulus script.

Starting the experiment

Starting the experiment takes 4 steps:

Start the program by dubble clicking chatter.py.
This screen should pop up.

Enter the participant number or code.
Click on the program screen and press SHIFT + F10.
A textbox will appear. Enter a subject code and press OK. Do not include "\" in this code.
Click here to see a screenshot.

Enter the stimulus file
Click on the program screen and press SHIFT + F11.
A file browser will appear. Select your stimulus file and press OK.
Click here to see a screenshot.

Control the parameters
If you doubt that you have entered the correct participant code or stimulus file you can press SHIFT+F9.
The program will print the parameters (see screenshot). Press SHIFT+F12 to erase the screen before continuing.

The program is ready for the participant now!

The experiment and the participant

The participant should start the experiment by clicking the "verbind/connect" button. This will start a little animation that should convince the participant that he or she is connected to an fellow participant (see screenshot).

The participant will then be prompted (in the message box at the left of the screen) to press enter to start the experiment. This will start  this sequence of events:
  1. The computer will indicate(in the message box) to be "thinking".
  2. The computer indicates to be "writing a message".
  3. The "message" (the prime sentence)  will appear in the box on the left of the screen of the program.
  4. The participant is prompted to decide whether the sentence offered by the computer matches the picture shown. He or she can answer using F1 (yes) or F2 (no).
  5. A new picture is shown.
  6. The participant is prompted to describe this picture. He or she can "send" the message by pressing the "send" button or pressing ENTER.
  7. Go back to number 1 - the cycle start all over.

The output

How does the output of chatter.py looks?

Chatter.py will make a separate output file for each participant, based on the code of the participant. The file name will be the same as the participant code.

If you enter, by mistake or on purpose, the same code twice no output will be erased. Output will always be appended to existing output.

Click here to see an example of the output.

Problems and their solution

Possible problem 1: You're not using Windows but Linux, Mac, ...

You can run the program on various systems (This is one of the strong points of Python). Running the program still requires installing Python and PIL. Personally I have no experience with Python on other systems than Windows. Therefore you should consult their respective website for more info on how to do this.

This book has a great introduction on how to start with Python on various OS:

Learning Python
Mark Lutz, David Ascher
Second Edition December 2003 
ISBN: 0-596-00281-5

Possible Problem 2 : The icon is not a snake.

If the icon of chatter.py has not changed to a snake after installing Python, you will have to tell Windows that it should open *.py files with Python. Under windows XP the problem is solved like this:
  1. Right click on the file.
  2. Choose "Open with..."
  3. Choose "Choose Program"
  4. If prompted choose the option "Choose from a list"
  5. Click "Browse"
  6. Navigate to the folder where Python was installed, if you followed my instructions about confirming the default settings during the installation this should be something like "C:\Python24".
  7. Click on "Python.exe"
  8. Choose "Always open with this program".
  9. Problem Solved?
Dieter Vanderelst
Updated: June 22, 2005


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