Foreword

Read this if you want to find out more about Amazon Mechanical Turk (AMT) and how psiTurk can help you run web-based experiments on AMT painlessly and quickly. This section will also tell you what problems psiTurk does and does not solve and help you gauge whether it will be useful to you.

What is Mechanical Turk?

Amazon Mechanical Turk (AMT) is an online platform that lets you post a wide variety of tasks to a large pool of participants. Instead of spending weeks to run experiments in the lab, it lets you collect data of a large number of people within a couple of hours.

Some key terminology for understanding the AMT model:

• HIT (Human Intelligence Task):
  • A unit of work (e.g. a psychology experiment)
• Requester:
  • The person or entity that posts HITs (e.g. a researcher or lab)
• Worker:
  • The person that completes HITs (i.e. a participant in your study)

Workers get paid a fixed amount for each HIT which is determined by the requester. Requesters can also make bonus payments to specific workers. Amazon takes a small percentage from each payment.

What is psiTurk?

AMT provides some very basic templates that you can use to design HITs (particularly questionnaires), but these will most likely not serve your purposes as an experimenter. The psiTurk toolbox is designed to help you run customized web-experiments on AMT. Specifically, it allows you to:

1. Run a web server that hosts your experiment
2. Interact with AMT to post HITs and recruit, filter, and pay participants (AMT workers)
3. Design and test the actual experiment

psiTurk also includes a web-based "dashboard" that lets you manage most of your AMT activity with a simple browser-based user interface.

Do I have to learn how to code?

Yes. To run your experiment in a web browser you need to have at least some basic web programming skills (especially using HTML, CSS, and JavaScript).

Fortunately there exist a lot of resources and tutorials that can help get started. If you are completely new to web programming, you might want to check out Codeacademy, for example, for interactive tutorials on building websites.

Once you mastered the basics, you can take advantage of the vast number of libraries and tools that can help you to build complicated and clean-looking experiments with the support of a large community of users.

To get you started, psiTurk provides a fully functioning example experiment (Stroop task) that you can use as a template for your own study. psiTurk also includes a library of basic JavaScript functions that you can insert into your code to handle page transitions, load images, and record data.