Can you teach old dogs new tricks?

Data:
Nutmeg

	Session time	Time at heel
Session 1	10 minutes	1 minute, 32 seconds
Session 2	15 min	4 min, 51 sec
Session 3	15 min	7 min, 36 sec
Session 4	15 min	7 min, 50 sec
Session 5	15 min	9 min, 43 sec

Tess

	Session Time	Time at heel
Session 1	10 min	2 min
Session 2	15 min	9 min, 46 sec
Session 3	15 min	7 min, 19 sec
Session 4	15 min	11 min, 6 sec
Session 5	15 min	10 min, 10 sec

Analysis:

After session:	Ratio between times: (Nutmeg/Tess)
1	0.765
2	0.496
3	1.038
4	0.705
5	0.956

Conclusion:
My hypothesis was mostly supported. My 12-year-old dog, Nutmeg, did learn more slowly than my 2-year-old dog, but usually by less than a ratio of 1/2 (0.5). Also, for session 3, I trained the dogs on the street instead of in my driveway. In the street, there are more distractions, and it is easier for Nutmeg to ignore these because things aren't as "new" as they are for Tess. In adverse conditions, an older dog may actually have a slight advantage over a younger dog because of life experiences.

Another thing I noticed was that Nutmeg's time at heel increased steadily, while Tess's jumped around. This shows that while older dogs may learn more slowly, they also learn more steadily than younger dogs.