Probability or statistical expected average: How to determine a success or failure

Hey,
(I am a NOOB in statistics)
I am trying to determine whether my experiment results indicate a success or just turns out as it would have without my independent variable.
40 participants where given the task to pick the 1 right object out of 5 objects. (Subliminal stimuli with the correct object was primed = independent variable)
The chances to do it randomly in:
1. attempt: 1/5
2. attempt: 1/4
3. attempt: 1/3
4. attempt: 1/2
5. attempt: 1/1
Here it could be argued that a correct pick in the 3. attempt is a success??
BUT! : Before conducting the experiment, I ran 10.000 simulations in a program that was set to pick a random number out of 5 and count the attempts. The average number of attempts turned out to be 3 which also is the average in my experiment.
Looking at it from this angle 3 is no longer successful, because it was somehow expected.
Which approach is most correct one to use, for determining an effect or no effect?
There might be a very clear and logic answers to this that have been posted and explained for ages, but i don’t know what to search for. So please be nice!
Thanks in advance!