Collecting Single OR Double Key Presses

[Jordan]

I sent a long-winded e-mail a few days ago, but just realized I could sum it up in one question:

Is there a way to collect single OR double (i.e., two simultaneous) key presses in a given trial?

Thanks in advance.

[jarvis24]

To make sure I'm clear on what you mean by "or"... Do you want to give them the option to respond twice, but allow them to respond only once if they so choose?

[Jordan]

Exactly.

I want them to have the option of replying with either a single key press, or with two simultaneous key presses.