Table 2.

Stimulus pairs

Medium pairsTexture pairs
Sawdust vs sandYellow fuzzy vs reversed yellow fuzzy
Gravel vs plastic beadsWaxed paper vs fine sandpaper
Ribbon vs crinkled paper stripsVelvet vs reversed velvet
  • The exemplars within a dimension (medium or texture) were always used in pairs. No two rats within a group received the same combinations, but groups of virgin and mother rats were matched.