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Keyboard responses

Keyboard responses are collected with the keyboard_response item.

Key names

Keys are generally identified by their character and/ or their description (depending on which is applicable). For example:

  • The / key is named 'slash' and '/'. You can use either of the two names.
  • The a is named 'a'.
  • The left-arrow key is named 'left'.

If you don't know what a particular key is named, you can:

  • Click on the 'List available keys' button; or
  • Create a simple experiment in which a keyboard_response is immediately followed by a feedback item with the text '[response]' on it. This will show the name of the previously collected response.

Correct response

The Correct response field indicates which response is considered correct. After a correct response, the correct variable is automatically set to 1; after an incorrect response (i.e. everything else), correct is set to 0; if no correct response is specified, correct is set to 'undefined'.

You can indicate the correct response in three main ways:

  • Leave the field empty. If you leave the Correct response field empty, OpenSesame will automatically check if a variable called correct_response has been defined, and, if so, use this variable for the correct response.
  • Enter a literal value. You can explicitly enter a response, such as 'left' in the case of a keyboard_response item. This is only useful if the correct response is fixed.
  • Enter a variable name. You can enter a variable, such as '[cr]'. In this case, this variable will be used for the correct response.

Allowed responses

The Allowed responses field indicates a list of allowed responses. All other responses will be ignored, except for 'Escape', which will pause the experiment. The allowed responses should be a semicolon-separated list of responses, such as 'a;left;/' for a keyboard_response. To accept all responses, leave the Allowed responses field empty.

Timeout

The Timeout field indicates a timeout value in milliseconds, or 'infinite' for no timeout. When a timeout occurs, the following happens:

  • response_time is set to the timeout value, or rather to the time it takes for a timeout to be registered, which may deviate slightly from the timeout value.
  • response is set to 'None'. This means that you can specify 'None' for the correct response a timeout should occur; this can be useful, for example, in a go/no-go task, when the participant should withold a response on no-go trials.

Collecting keyboard responses in Python

You can use the keyboard object to collect keyboard responses in Python: