importstatement into the top of your source file:
mturk) jobs using its MTurk domain-specific language (DSL).
Hello world!. If you see
Hello world!in your output, move on to the next step. If not, read the
sbtoutput carefully to diagnose and fix the problem.
athat stores an instance of
mturk. AutoMan needs what we call a platform adapter in order to know which service to connect to. In this case, we are connecting to Mechanical Turk.
argsis an argument array, and
args(0)is the first element of that array (if you come from Java, note that arrays in Scala use
). These are the same credentials you downloaded in an earlier step of this tutorial.
which_onethat takes no arguments. It is important to note that
which_oneis just an ordinary function in Scala, although it does behave in some special ways that we will describe in the next section.
radioconstructor. "Radio button questions" allow MTurk users to select one of n options.
budget: This parameter specifies the maximum amount of money AutoMan will spend on this task. AutoMan always tries to spend less. If the cost of a task exceeds the budget you supply, AutoMan will shut down the task and return a "low-confidence answer."
text: This parameter supplies the text of the question. You describe what you want workers to do here.
options: This parameter supplies the valid options. Since this is a radio button question, each option will produce a radio button. The
choiceconstructor takes three parameters:
Symbol. You can think of a
Symbolas a special string designed for easy comparison. This parameter is not visible to MTurk workers.
name, which is visible to MTurk workers.
confidence(not shown): This parameter stands for the statistical confidence level and is a floating-point number between
1(exclusive). A number approaching zero tells AutoMan that virtually any answer is fine. A number approaching one tells AutoMan that you want to be very certain that it is correct. Although the
confidenceparameter is not shown above, it is set to the default of
0.95, which is something of a standard threshold across empirical science.
which_one()inside our AutoMan block.
mturkinitializer, this program will post jobs to the MTurk sandbox. When you run this program in the sandbox, no work will get done, because only the live production site has active workers. You must simulate the job yourself. We describe the process of simulating a job in the section titled Pro Tip: Use the MTurk Sandbox.