Experiment 2: Context generalization following delayed context shift

1. Experiment 2: Context generalization following delayed context shift

2. Hypothesis 1 • It was hypothesized following an immediate delay subjects would be able to discriminate between two contexts • Subjects trained in context A and immediately tested in context B for would not run down the runway as quickly in B as they did in A; whereas subjects trained in context A and tested in context A would show little to no difference in their time to run down a run way

3. Hypothesis 2 • It was hypothesized following an longer delay subjects would generalize the two contexts as indicated by similar performance between the two groups • Subjects trained in context A and tested in context B a week later would run down the runway as quickly in B as they initially did in A suggesting that the subjects generalized the two contexts; similarly subjects trained in context A and tested in context A would show little to no difference in their time to run down a run way

4. Subjects • 16 female Long-Evans rats approximately 90-120 days old • Subjects were quasi-randomly assigned to one of four groups (n=4 per group)

5. Apparatus & Materials • Both runways had the following dimesions 61” long X 5” wide and the walls 4” high and contained a food cup at the end; food cup contained one fruit loop • Context A • Walls were gray • Floor was a wire grid • 44” off the floor • Covered with a plexiglass lid • Normal light conditions

6. Apparatus & Materials • Context B • Walls were white • Floor was covered with coarse grit sandpaper • 24.5” off floor • No lid on top • Illuminated by three desk lamps • Contained lemon scent throughout

7. Figure 1a & 1b Context A

8. Figure 2a & 2b Context B

9. Procedure • The first 3 days of the study were used as pre-testing in order to get the subjects acclimated to context A • Each day every subject was given 5 trials, a trial consisted of the subject starting at one end and running to the other end and ended once the subject began eating the fruit loop • Each subject was given 5 minutes per trial, if the subject failed to perform they would be removed and the next trial would begin • Once the subjects reached asymptotic performance all subjects were given one day of testing in context A in order to establish baseline performance • Each subject was given 3 trials

10. Procedure • Following baseline testing subjects were quasi-randomly assigned to one of four groups (n=4 per group) • Each subject was given 3 trials • Two groups were either tested in context A or context B two days after baseline testing • The other two groups were tested in context A or context B one week after baseline testing

11. Procedure • Initial performance as well as baseline performance was analyzed to determine whether there were any group differences • The dependent measure was the difference in time it took to run down the alley from baseline to testing • Averaged across 3 trials • Positive score indicates improved performance; subject running quicker • Negative score indicates that it took longer to reach the end

12. Initial performance

13. Initial performance

14. Initial performance

15. Initial performance • A context X delay X day repeated measures ANOVA demonstrated a significant effect of day F(2,24)=74.29, p <.05) and no significant group or delay differences (p’s >.05) • This suggests that all subjects were performing similar prior to any experimental manipulation, but were demonstrating improved performance by the final day of pretesting as indicated by a reduced time to reach the end of the alley

16. Baseline

17. Baseline

18. Baseline

19. Baseline • A context X delay ANOVA demonstrated no significant differences between any of the groups (p’s >.05) • This suggests that during baseline testing there were no significant difference between any of the subjects’ performance

20. Mean difference from baseline * p<.05

21. Mean difference from baseline

22. Mean difference from baseline

23. Mean difference from baseline • A context X delay ANOVA found a significant main effect for context , F(1,12) = 8.35and delay F(1,12) = 8.35, as well as a significant context X delay interaction F(1,12) = 15.78, p’s<.05 • The significant effect of context indicates that subjects tested in a different context performed significantly poorer, as indicated by a slower running time during testing • The significant effect of delay suggests that subjects tested immediately following baseline testing were able to discriminate between the two contexts • The significant context X delay interaction suggests that subjects tested in a different context 2 days after baseline are able to discriminate between the two environments whereas subjects tested in the different context 1 week later is generalizing the different context as indicated by similar performance to subjects tested in the same environment as baseline at both 2 days and 1 week

24. Some extra information • There are numerous books and articles about this topic • Generalization and discrimination of context • Recall cues • Contextual learning • Remember to discuss this in an overall context, don’t just simply regurgitate try to integrate • The challenge in this is to try to relate this to other aspects of the literature or even find conflicting studies • In other words why are our findings important, what can people take from this study

25. Some extra information • An important paper • Gisquet-Verrier, P., & Alexinsky, T. (1986). Does contextual change determine long-term forgetting? Animal Learning & Behavior, 14(4), 349-358. • Can use this, but it can’t count towards the two paper min. requirement (but it is very useful) • http://www.psychonomic.org/search/view.cgi?id=10855

26. Some extra information • Remember if you need help ask