[open] Help with variable probabilities

bstilwel

Hey, I'm a Master's student building my thesis in OpenSesame. I love the program! I'm having some difficulty figuring out how to program probabilities associated with some of my variables. I'm doing a value-driven attentional capture study and I'm rewarding one group with a high reward and another with a low reward. However, if the current trial is a "high reward group member" then there should be an 80% of receiving the high reward (5 cents) and a 20% chance of receiving the low reward (1 cent). If the trial is a "low reward member" then 80% of the time they will get a low reward, and 20% they will get a high reward. Each group has 5 members and I want each block to have the same 80/20 probabilities. So in block 1 I want group members A,B,C,D to be associated with the high reward and member E to be with the low reward. Then block 2, have B,C,D,E as high, A as low, and so on for 5 blocks. This way each member is a high reward for 80% and a low for 20% across blocks (high for 4 blocks, low for 1). My initial attempt has been to create 5 blocks and then in the variable window, just manipulate the amount of times each member is called within each block. I would do this for all 5 blocks. However, I'm not sure how to manipulate the reward probabilities within the blocks. So on any given trial, there is the 80% chance that a high reward member actually receives a high reward (20% it will get a low reward instead). Any suggestions on how to more efficiently handle these issues would be greatly appreciated!

eduard

Hi,

Could you explain what exactly you mean with "group member"?

As far as I understand, it could be enough if you only specify in the block_loop which group member is associated with the low reward, (or high reward, depending on which is the single one). In doing so, you only need 5 lines to cover every conditions and the other group members, you can assign by default the corresponding likelihood (in your case high reward). Doing this with an inline_script should be fairly easy.

let me know, if you need more explanation.

Best,
Eduard