If this template helps then use it. If not then just delete and start from scratch.

**OS** (e.g. Win10): Mac 10.12.6

**PsychoPy version** (e.g. 1.84.x): PsycoPy3

**Standard Standalone? (y/n)** If not then what?:

**What are you trying to achieve?:**

Hello, I ask you already sorry for how I am going to explain myself but I am completely new in the use of programming languages! I am trying to create using both builder and coder a multi-armed bandit task. So what I need to create is a screen with a cross fixation point in the middle, where behind is going to appear the response (reward).

I’d like to have 3 arms (3 options of response), arm1=an image of a toy, arm2=another toy, arm3= no response. each arm should have an underlying probability of giving the positive feedback (happy face of a child), the neutral feedback (neutral face) and a negative feedback (distressed face). the probability is around 0.75 for the successful arm and it is not stable. it should change, in order to see how quickly the participant learn the new rule and understand which arm is the successful one.

The idea is that every ten trials a coin is flipped and whether 0 the underlying probability doesn’t change, whether 1 it does.

I don’t understand how should I build my Condition file, since there is no a 100% sure correct answer I don’t know how to add the probability condition.

plus, the “non-response” arm in my mind should be the option of inhibit a response (so wait, let’s say more than 2 s), I can I do this?

I know I have been pretty vague but any suggestion or link is welcome!

**What did you try to make it work?:**

I don’t understand the structure I need to create for my excel component.

How can I create an option that stands for “no option”?

How do I attribute the underlying probability?

How do I say that that probability should change?

**What specifically went wrong when you tried that?:**

Include pasted full error message if possible. “That didn’t work” is not enough information.

if $Valuefeedback ==1:

^

SyntaxError: invalid syntax

here I tried to create a feedback for every response (1=happy face, 0=neutral face, -1=negative face) but I can’t make it work.

Thank you so much in advance!