for cing ▁cont ingen cies ▁in ▁the ▁environment ". ▁The ▁dogs ▁initially ▁behav ed ▁as ▁though ▁they ▁" expected " ▁a vers ive ▁events ▁and ▁that ▁the ▁only ▁way ▁to ▁prevent ▁these ▁events ▁was ▁through ▁ag gression . ▁The ▁dogs ▁were ▁therefore ▁a ▁highly ▁selected ▁subset ▁that ▁had ▁not ▁learned ▁strateg ies ▁for ▁cop ing ▁with ▁threat . ▁ ▁Each ▁dog ▁was ▁trained ▁to ▁respond ▁to ▁a ▁set ▁of ▁ 1 5 ▁commands ▁taken ▁from ▁the ▁A K C ▁standard ▁for ▁CD X ▁ob ed ience . ▁The ▁commands ▁were ▁selected ▁to ▁provide ▁control ▁over ▁the ▁dog , ▁and ▁included ▁" heel ", ▁" stand " ▁" go ", ▁" come ", ▁" hold ", ▁" drop " ▁and ▁" s it ". ▁These ▁behav iors ▁were ▁term ed ▁" s af ety ▁behav iors ". ▁Training ▁was ▁divided ▁into ▁ 9 ▁stages , ▁each ▁of ▁which ▁was ▁composed ▁of ▁ 5 – 2 0 ▁twice ▁daily ▁training ▁sessions . ▁D ogs ▁could ▁only ▁progress ▁to ▁the ▁next ▁stage ▁after ▁passing ▁a ▁test . ▁On ▁average , ▁dogs ▁took ▁ 1 0 – 1 5 ▁sessions ▁to ▁complete ▁each ▁stage . ▁After ▁training ▁on ▁basic ▁commands , ▁the ▁dogs ▁were ▁trained ▁to ▁perform ▁the ▁behav iors ▁they ▁had ▁already ▁learned ▁in ▁order ▁to ▁avoid ▁progress ively ▁increasing ▁electric ▁shock . ▁After ▁that , ▁they ▁were ▁condition ed ▁to ▁perform ▁a ▁safety ▁behavior ▁to ▁avoid ▁a ▁" s af ety ▁tone " ▁that ▁let ▁them ▁anticip ate ▁the ▁shock . ▁In ▁later ▁stages ▁of