I’m running an experiment where participants are shown series of morphed faces (each face is a combination of 2 faces). The morphed face can be either their face (Person A) or their best friend’s face (Person B), mixed with a stranger’s face (Person C). There are 6 different blocks; 3 blocks containing instructions for the participant to judge if the face contains their own face, and 3 blocks containing instructions for the participant to judge if the face shown contains their best friend’s face. Is there any way I can code their responses as correct or not differently for different blocks?
I.e.
For Block 1 (self instructions):
-face 1 is a mix of person A & person C
- participant says yes - coded as correct
- participant says no - coded as incorrect
-face 2 is a mix of person B & person C
- participant says yes - coded as incorrect
- participant says no - coded as correct
For Block 2 (best friend instructions)
-face 1 is a mix of person A & person C
- participant says yes - coded as incorrect
- participant says no - coded as correct
-face 2 is a mix of person B & person C
- participant says yes - coded as correct
- participant says no - coded as incorrect
Yes, this can be done at the event level.
You can designate which response is correct for each event in the Event Editor under the Correct Response tab.
Alternatively, you can create a stimulus list and use code values to represent who’s in the merge. Then you can automatically have the list imported as events. This way you only have to specify which key press is a correct response once for the block.
Yes I currently am using a stimulus list and I have one event which holds the entire stimulus list. When I go to the Event Editor I am able to code the correct response, but the coding is thus the same for all blocks. So should I make a separate event for each block that I want coded differently, and code the events accordingly
The stimuli should be coded in the stimulus list editor. Then you can set the correct response in the event editor based on the code values. You will need different events for the different blocks, but most of the work should be in the process of coding the stimuli, so this shouldn’t be particularly difficult.
Okay so my stimuli are in a stimulus list and coded
they are coded in terms of 3 variables:
- the face judged (participant’s face, stranger’s face)
- face mix (percentage of each face in the mix)
- type of face (good, bad)
Essentially only the first variable (face being judged) is important for my correct response. I also have 2 groups (a left hand reports yes/right hand reports no group, and a left hand reports no/right hand reports yes group). This is also important for deciding the correct response because they get different instructions depending on what group they are in.
How can i put the correct response in taking into account both of these (face judged, and the group they’re in)?