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. Author manuscript; available in PMC: 2009 Apr 22.
Published in final edited form as: Neuroscience. 2008 Feb 19;153(1):63–71. doi: 10.1016/j.neuroscience.2008.01.064

Table 1.

Testing stimuli in the ID/ED task

Task Testing pair 1 Testing pair 2 Never relevant attribute
SD Clove/navy paper+
vs. nutmeg/navy paper		 Clove/white paper+
vs. nutmeg/white paper		 Texture e.g. All bubble wrap
CD Clove/navy paper+
vs. nutmeg/white paper		 Clove/white paper+
vs. nutmeg/navy paper		 Bubble wrap
ID Cinnamon/thick yarn+
vs. patchouli/thin yarn		 Cinnamon/thin yarn+
vs. patchouli/thick yarn		 Corduroy
REV1 Patchouli/thick yarn+
vs. cinnamon/thin yarn		 Patchouli/thin yarn+
vs. cinnamon/thick yarn		 Corduroy
ED Large beads/vanilla+
vs. small beads/jasmine		 Large beads/jasmine+
vs. small beads/vanilla		 Velvet
REV2 Small beads/vanilla+
vs. large beads/jasmine		 Small beads/jasmine+
vs. large beads/vanilla		 Velvet
Learned irrelevance Small beads/vanilla+
vs. large beads/jasmine		 Small beads/jasmine+
vs. large beads/vanilla		 Satin

An example of a testing schedule for a subject whose initial, relevant stimulus dimension was odor for the SD, CD, ID and REV1 is shown. There are two additional stimulus attributes present for every trial, digging media and texture. Testing pairs 1 and 2 are randomly alternated at all stages of testing. During testing of the SD, the stimulus pairs varied on a single dimension e.g. odor. Subsequent to the SD, the stimulus pairs vary on two dimensions e.g. odor and digging media. The alternation of stimulus pairs trains the animals to focus attention on one stimulus attribute and disregard the variable, irrelevant attribute e.g. digging media as well as the never relevant attribute. The variable, irrelevant attribute e.g. digging media in the initial stages of testing becomes the relevant attribute in the ED. A novel exemplar of the never relevant dimension is introduced subsequent to REV2 to insure that rats learned to successfully ignore this stimulus attribute e.g. texture. The order of testing of the stimulus pairs was constant across subjects but the relevant, variable irrelevant and constant irrelevant dimensions were counterbalanced across subjects as described in the Experimental Procedures.