Schedules of reinforcement

[Charmz]

So there's this question from the 2006 psych paper:

Question 32
Which schedule of reinforcement results in the slowest acquisition of behaviour?
A. fixed ratio
B. fixed interval
C. variable ratio
D. variable interval

And the answer says D, but I would have imagined it should be B because aren't you just getting rewarded after, say, every two minutes and you don't need to put in any effort to acquire the learning whereas with D you don't know at what interval you are going to get a reward so you try and you acquire the learning t some extent and you don't know when exactly you are going to get the reward and what you need to do so wouldn't you try to do the task?

I'm just super confused and the explanation was really useless; 'This question may be taken as an indicator of the degree of detail in which schedules of reinforcement should be studied.'

My psych teacher didn't know either.

[Felicity Wishes]

It is definitely D. Each schedule has what you would call a response rate. The one with the quickest response rate is fixed ratio and then variable ratio, then fixed interval and last variable interval, meaning that it is the slowest one.

Also, ACQUISITION is moderate for fixed internal as the time is always the same so it becomes easy to establish the association while variable interval takes longer because it is less structured. Hope that helps you.   

Do you have access to the Grivas textbook?

[brenden]

Just to add to Felicity's answer

Which schedule of reinforcement results in the slowest acquisition of behaviour?
A. fixed ratio
B. fixed interval
C. variable ratio
D. variable interval

Okay so we know acquisition is the establishment of a previously unlearned response. Fixed ratio is definitely going to be the fastest as if we have a hungry rat that wants food and you give it a pellet for every 5 clicks of a button, it's going to start smashing the button like nothing else so it gets an endless stream of pellets, so the behaviour of clicking is acquired very quickly.
Now your problem with b was 

I would have imagined it should be B because aren't you just getting rewarded after, say, every two minutes and you don't need to put in any effort to acquire the learning

Your logic is the reason you are wrong. If you don't need to put in any effort to acquire the learning it's going to happen relatively quickly. You are getting rewarded after every two minutes etc, so the behaviour will occur every two minutes. The dependability is key here; it separates the acquisition speed for d) variable interval as in d) the organism has no idea what to expect and it's hard to associate the behaviour with any given consequence as there is no consistency with a variable amount of time.
Variable ratio is the same deal as fixed ratio, the organism will just start smashing the button once it's made the association that the reinforcement comes from the clicking. General rule of thumb => ratios are better for acquiring behaviour than intervals. If we accept this as fact then it is a logical deduction that varying amounts of anything [time or numbers] will lead to a slower association than fixed amounts. Following this rule and the subsequent logic, D has to be the answer.

[Charmz]

Thanks guys. I do have access to the Gravis book but I couldn't find it in there. Anyway thanks again.

[Felicity Wishes]

Thanks guys. I do have access to the Gravis book but I couldn't find it in there. Anyway thanks again.

Check out the graph page 486. I find that helpful for this sort of question.