Presentation on theme: "Operant Conditioning: Sniffy the Rat 210 Lab Assignment #2 – 2014 Due: Friday April 4 th (last day of classes)"— Presentation transcript:
Operant Conditioning: Sniffy the Rat 210 Lab Assignment #2 – 2014 Due: Friday April 4 th (last day of classes)
Today 1)Brief background: Operant conditioning and the reinforcement schedules we’ll use 2)Using the Sniffy Program 3)Steps to completing the assignment 4)Walkthrough of CRF training (and brief explanation of how to start PRF training) 5)Assignment Outline – lab report
Purpose The Sniffy program will help you understand operant conditioning and give you first-hand experience with these concepts: Magazine training Shaping behavior Partial Reinforcement (PRF) schedules Continuous Reinforcement (CRF) Fixed Ratio (FR) Variable Ratio Schedule (VRF) Fixed Interval (FI) Variable Interval (VI) Acquisition Extinction
Operant Conditioning Increases the rate of a desired behavior by reinforcing that behavior when it occurs In our case, we want Sniffy to bar-press We will reinforce him with food pellets
Schedules of Reinforcement – Main Types: Continuous Reinforcement (CRF) Rewarded every time the desired behavior occurs Every time Sniffy presses the bar, he will get a food pellet Partial Reinforcement (PRF) Rewarded some times when behavior occurs; not every time e.g. Sniffy might press the bar 5 times and only get rewarded once.
PRF Schedules – 4 Types: Fixed - Reward happens after a set number of responses or time Variable - Reward happens around a certain average Ratio - Bar-pressing is the determinant for reward Fixed Ratio (FR) - Pellet is delivered after a set number of bar-presses Variable Ratio (VR) - Pellet is delivered after an average number of bar- presses Interval - Amount of time is the determinant for reward Fixed Interval (FI) - Pellet is delivered after a set amount of time passes Variable Interval (VI) - Pellet is delivered after an average amount of time passes 12 34
Materials needed The lab manual (on Moodle) read this before you start Sniffy Program On any campus lab computer: Click My Computer Apps on Caesar (‘S:’ drive) Sniffy folder double click the Sniffy icon to open the program Stop watch, or stop watch app on your phone Paper & pen
Project components Shaping an Operant Response: Observe Sniffy’s base-line behavior for 10 mins Magazine Training Shaping Bar-Pressing by Successive Approximation Extinction Spontaneous Recovery PRF Schedules: Fixed Ratio 20 extinction Variable Ratio 20 extinction Fixed Interval 20 extinction Variable Interval 20 extinction
Observing baseline behavior For 10 minutes, observe Sniffy’s behavior Pay attention to what he does and get an idea of what kind of behaviors you’ll be reinforcing later on Planning ahead a bit will help with the next part Record how many times Sniffy bar-presses on his own in the 10 minutes DO NOT reinforce him
These dotted lines show you 5- minute increments The cumulative record (CR) will show you how Sniffy’s training is progressing bar magazine/hopper water
The ticks on the cumulative record show when Sniffy bar-presses. The line also moves up when he presses the bar, allowing you to track training progress. Sniffy may bar press a few. My Sniffy bar-pressed twice during the 10 min observation time.
Magazine Training Using the spacebar or your mouse, drop a pellet from the hopper When Sniffy approaches and eats it, give him another pellet Consider Sniffy magazine-trained when he approaches the hopper as soon as you drop a pellet (10-15 reinforcements) You can test his training by waiting until he is far away from the hopper (nearest to you) and dropping a pellet: if he goes to eat it, he’s magazine-trained
Training Sniffy to bar-press Training by successive approximation Reinforce behavior that is closer and closer to the desired behavior Reinforce: drinking, rearing on the rear wall, going near the food hopper, passing in front of it Fixation If you reinforce one behavior too frequently (e.g. reinforcing rearing on the rear wall too many times in a row), Sniffy will fixate on that behavior, rather than what you are trying to shape Note I cannot stress enough how important it is to devote your FULL attention to this part of the assignment. Training Sniffy to bar-press takes about 30 to 45 mins if you pay attention and reinforce him appropriately. It can take several hours if you aren’t giving it your full attention.
Bar-pressing cont. Slowly wean reinforcement down to only when he is rearing near the bar, or in front of the magazine Sniffy will start to bar-press by himself more and more frequently stop reinforcing him manually and let him continue to bar press until the CR resets two times. Time him to make sure he’s bar-pressing at a frequency of 4-5 presses per minute. If he is, your training was successful! Go to File Save As Name him something appropriate (SniffyCRF.sdf, etc.). You’ll be working from this saved Sniffy file several more times, so saving is vital. You don’t want to have to train a new Sniffy later. Immediately save Sniffy to your H: drive, USB drive, etc.
My CR has resent by going back to the bottom twice. At this point he’s bar-pressing 4-5 times per minute.
Extinction Trials Click Parameters menu Training Schedules Extinction Click OK Sniffy will no longer be on a CRF schedule – He won’t get a pellet when he presses the bar Time and Record: Number of non-reinforced bar presses in the first 2 minutes of extinction Time to complete extinction (if he presses 3 times or less in 5 minutes we’ll consider that extinction)
23 Spontaneous Recovery Next we’re going to test spontaneous recovery after a ‘time out’ (think of this as an overnight break from the chamber) Click Parameters Remove Sniffy for Time-Out OK After Sniffy is placed back in the chamber, time and record: Number of bar presses in first 2 minutes Amount of time required for Sniffy to completely extinguish a second time Save this Sniffy (e.g. SniffyEXT.sdf) and print your results You’re finished with CRF training!
26 Note on Cumulative Records You will print a copy of CRF, extinction, and spontaneous recovery cumulative records to turn in with your report Label the printout (in pen): When was acquisition complete? When was extinction instituted? When was extinction complete? When was spontaneous recovery instituted? When was extinction complete the second time? Print and make notes as you go through the steps, not after you’re finished everything – it might be hard to remember later. Check the manual for more info on what you’ll need to print as you move through the steps, and what you’ll need to label on the printout for each training schedule
PRF Training I’ll show you how to do the one PRF training schedule Fixed Ratio (FR) 20 Teach Sniffy to bar-press 20 times for a food pellet The procedure to carry out this training schedule applies to all the others First, open your original CRF Sniffy We can’t start out with FR20, we have to start out with a lower ratio Remember how fast extinction occurred? If we start out at FR20, or FR15, or FR10, it’s likely that he won’t learn the new schedule
What I’ve selected means Sniffy will get a pellet after 4 bar- presses (FR4) Use for interval schedules Use for fixed schedules
Sniffy’s response rate will be lower at first
Looks like he’s learned the new schedule
Wait until Sniffy has been reinforced 15 times, then increase the # of responses before reinforcement (by 3 or 4 responses)
Repeat these steps until you’re up to FR20
Tips Give yourself lots of time to complete training – start as early as you can I can give you rough estimates of how long each part will take: Observing behaviour and magazine training: 30 mins CRF – from 30 mins to an hour Assuming you’re paying attention! I’ve been told it can take several hours if you’re not. The PRF schedules (+ extinction) take about an hour each If you forget to start your stopwatch, you can tell 2 minutes (or whatever time you need) using the CR and a ruler Print the CR and label it before moving on to a new step. Read the instructions fully before starting – it’s hard to do it as you’re working on training Saved full labs from last term
Lab Assignment #2 Due April 4 th (in class) After you’ve trained Sniffy and printed your CRs, write a lab report detailing your findings More info on lab report requirements are in the manual Components: Title page Partial Intro Outline hypotheses for each training schedule (how do you think they will they compare to one another?) Method Results Report your observations made during steps outlined in the manual (acq/ext times, behavioural observations, etc.) Discussion Address questions listed in the manual Refs (textbook, chapter 5) CR printouts (labelled and with required notes)