By having 4 unique toys, should be able to do 2 tests on each rat: a short-term test (e.g. 1 hour post-training) and a long-term test (e.g. 24 hours post-training), with 2 different pairs of toys.
Kong Classic Dog Toy (large) vs. Kong Jump'N Jack Dog Toy (medium).
Kong Classic Dog Toy (large) vs. Kong Jump'N Jack Dog Toy (medium).
''Note that Jump'N Jack has been discontinued.''
''Note that Jump'N Jack has been discontinued.''
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Kong Stuff-A-Ball (large0 vs. SHITEC Dog Chew Toy
[[File:Kongs4NOR.jpg|200px|thumb|right|Kongs used for rat NOR test]]
[[File:Kongs4NOR.jpg|200px|thumb|right|Kongs used for rat NOR test]]
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[[File:MoreKongs4NOR.jpg|200px|thumb|right|More Kongs used for rat NOR test]]