Peak Shift Writing Assignment
Complete and Write: (40 points altogether)
Graph: You will also be doing a graph of the three generalization gradients, bar-pressing numbers obtained in Exercises 5, 6, and 7—it will look much like the one on page 211 of your book. You may do this graph using SPSS, Excel, or by hand on graph paper (there is a graph paper file on Titanium which you can download, print, and use). Be sure to label your axes and each of your three lines. Don’t use colored lines as this won’t translate to black and white printing! This graph is worth 10 points.
Written Explanation: You will also be doing a verbal comparison of the three gradients and explaining the Peak Shift Effect observable on the S+/S- generalization gradient. I will do a brief lecture about this in lab. Chapter 13 of the Sniffy manual contains background information and there is an additional reading from a learning and memory textbook online in Titanium under Assignment 7 materials that is there for you to read. All the following issues are to be addressed in a coherent, logical, fashion. Do not treat each subsection as if it were a separate question that you give the briefest answer to. All issues are related to one another and are part of the whole discussion; however, don’t make it all one paragraph, please. You will be graded on the quality of your writing as well as the content. Each set of issues is broken out and enumerated separately, below, only to make sure that your attention is drawn to all points. This written section of the assignment should be typed, double-spaced and have sufficient detail so that it is a minimum of 1 to 1 ½ pages in length. You may use your lecture notes, the Sniffy chapter material and the other reading on the peak-shift effect to help you accomplish the job, as long as it is in your own words. This portion of the assignment is worth 30 points.
1) Data from Sniffy Assignment 5 produces and excitatory generalization gradient. The graph from Assignment 5 (you trained for this on Assignment 4) shows peak responding at what tone? Why? The excitement to respond for reinforcement generalizes around what stimulus (tone)? How does that influence behavior?
2) Data from Sniffy Assignment 6, produces an inhibitory generalization gradient. The graph from Assignment 6 (I did the training) shows maximum inhibition at what tone? The inhibition that influences behavior generalizes around what tone? How does inhibition influence behavior (the likelihood of bar-pressing)? That is, does internal inhibition produce bar-pressing or does it inhibit operant responding (bar-pressing, in Sniffy’s case)? These two gradients (excitatory and inhibitory) look quite different from one another—explain why.
3) In Sniffy Assignment 5, you get to see the effects of excitation, alone, on behavior. I Assignment 6, the effects of inhibition are visible in that generalization gradient. In Sniffy Assignment 7, the generalization gradient shows the effects of both excitation to respond for reinforcement associated with the S+ and inhibition of responding associated with the S-. The joint and interacting effects of both of these influences change the shape of the generalization gradient so that it doesn’t exactly resemble the simple excitatory gradient, nor does it look much like an inhibitory gradient. Further, the peak (maximum) responding is no longer at the S+. Where is it now? Why does one get that peak responding shift after discrimination training with S+/S- stimuli? Explain this explicitly and in some elaborated detail. Refer to the internal motivation states (as illustrated in those red bar-graphs during Sniffy training) of both excitation and inhibition to explain the mechanics of this peak shift. Don’t just say that excitation an inhibition interact—explain, specifically, how they interact. You gaining and demonstrating this understanding was the main point of these last 4 exercises!!