Vol.l•S? 54]• Lon•z, TheCompanion in the Bird's World 245 THE COMPANION IN THE BIRD'S WORLD BY KONRAD Z. LORENZ IntroductoryNote WnE• Dr. Lorenz'spaper on the 'Kumpan'• waspublished in 1935,it seemedto be such an original and importas•t contribution to our knowledgeof the instincts and behavior of birds, that I was as•xiousto have a summaw of its thesesand conclusions appear in the pages of 'The Auk'. Knowing that Dr. Lorenz was conversantwith English, I wrote to him, askingif he would consentto prepare suchan account of his own work, and he replied that he would be pleasedto do so if given sufficienttime. Dr. Lorenz's paper was delayed in reaching me from various causes. He found difficulty in summarizing a work which consistedin so large a measureof observa- tional detail, and accordingly has stressed those subjectsof the most theoretical importance; and he added: "I shall not refrain from using some new observations, and the resultsof experimentswhich have come to my knowledgesince the publica- tion of my paper." My function has been mainly editorial; and although it has seemedbest to condensesome parts of the author's manuscript, I trust that its value has not been impaired. The doctrine of 'releasers,' herein set forth,--or devices for the production of stimuli, which serve as the 'keys' to 'unlock' or releasethose 'innate perceptory patterns,' characteristicof the speciesand the individual, and which result in in- stinctive reactions,--seemsat last to offer a soundand satisfying explanation of that riddle so long embodiedin 'the secondarysexual charactersof birds,' and one which I believe that Darwin, when strugglingwith his 'Theory of Sexual Selection,' would have welcomedwith open arms.--FRA•c•s H. HERa•CK. THE CONCEPTION OF THE "RELEASER" IF WE observea man performinga numberof separateactions, each of which has for its object the samething and which, taken togetherand con- sidered as a functional unit, serve an end of definite survival value to the man himself, we shall not hesitate to infer two things: first, that the man, in performingthese actions, is consciousof their goal and that it is this very goal that constitutesthe purposeof all his movements;second, that in per- forming the several actionsof the sequence,he is constantly aware of the identity of the object toward which they are directed. On seeinga similar seriesof actionsexecuted by someanimal, we are prone to cometo the same conclusions,but both would be totally erroneousin casewe shouldhave to do with a seriesof purely instinctiveacts. Much seriousharm has been doneby confoundingthe biologicalend, or survivalvalue of {nstlnct{veaction, with the purposepursued by the animal as a subject. I cannot go into the details of my argument against this wldelyspread error, but for the purposesof this paper,suffice it to say that • 'Der Kumpan in der Urnwelt des Vogels (Der Artgenosse als aus16sendesMoment sozialer Verhaltungsweisen)' [The Companion in the Bird's World; the fellow-member of the species as a releasing factor of social behavior.] Journ. f. Ornith., vol. 83, pt. 2-3, 1935. 246 TheCompanion inthe Bird's World [July[Auk I considerinstinctive action as 'desiredreflex action', meaningthat instinc- tive action, while in no way purposivein itself and quite as rigid as any other reflex as to the coordinationof movements,yet in its very 'goingoff' constitutesthe purposeof all truly purposiveor appetitive behaviorever met with in animals. Beingappeted, sought or desired,is the one point in which instinctive action differs from all other reflex actions. The common reflexes,like unusedmachines, may lie idle indefinitely, as if waiting for adequatestimulation, without in any way inciting the animal to searchfor suchstimulation by purposivebehavior, as it certainly doesin caseof the instinctive reactions. It is the secondof the assumptionsmentioned that concernsus more closely;namely, that the animal, in consistentlytreating one definiteobject to a seriesof separateactions, must throughoutits acting, be aware of the identity of this object. Man, in striving to conquerhis environmentand to master the problemswhich it puts before him by connectingcause and effect,is confrontedwith the absolutenecessity of conceivingevery object he encountersas a permanentunit which remainsidentical throughout the changesof spaceand time. Not so the animal, moreespecially the lower animal, that doesnot masterits environmentby insightor learningbut is innatelyadapted to it by possessinghighly differentiatedinstinctive powers of response. The lower animal very rarely 'solvesproblems' as an individ- ual, and wheneverit doesso, this is only in an abysmallysimple way. As a rule, a lowerorganism either has solved a problemas a speciesby evolving instinctiveways of reactingthat fit everysingle one of the emergenciesthat normally occur,or its fails miserablywhen confrontedwith a problemfor whichit doesnot possessany suitableinstinctive responses. Since the in- nate coordinations of movement that we call instinctive actions are not adaptedto any goalor end anyhow,it sufficesthat everyone of them be re- leased,much as in reflexes,by a simplecombination of stimuli,if only this combinationis sufficientlycharacteristic of the biologically'right' situation; that is, of the one situationin which the performanceof the innately co- ordinated movements attains its full survival value. If an instinctive action is directedtoward a particularobject, its successfulperformance is inde- pendentof the animal'sperceiving this objectas a 'thing', that is, as a per- manentunit in spaceand time as we wouldperceive it. All that is needed on the part of the animalis the dispositionto respondwith just that reaction to certain stimuli characteristicof its particular object. The sea-urchin (Sphaerechinus)possesses a very complicatedreaction of combineddefense and flight, whichis of survivalvalue exclusivelyas a meansof escapingthe sea-urchin'schief enemy, the starfish(Asterias). The whole of this highly differentiatedsequence of singleacts is releasedby a singlechemical stimu- lus emanatingfrom the mucus coveringthe ambulacral tentaclesof the Vol.1937 541J LORENZ,The Companion in the Bird's World 247 starfish. Anothergood example is that of the biting reactionof the common tick (Ixodes). The tick will bite, or try to bite, any objectpossessing the two charactersof (1) smellingof butyricacid and (2) havinga temperature of approximately37 degreescentigrade. The releasingof comparatively complicatedsets of reactionsthrough a very simplecombination of stimuli, is characteristicof the greaterpart of all purelyinstinctive reactions and by no means exclusivelyof those of lower animals. The Jackdaw (Coloeus moncdula)possesses a very interestingreaction of defendingany fellow- memberof the speciesin the grip of somebird or animal of prey. ]?or a long time I have been familiar with the fact that my tame but free-living Jackdawswould furiously attack me if I grippedone of them in my hand, but I was very much astonishedwhen I inadvertently elicitedexactly the same responseby carrying a wet, black bathing-suitin my hand. Subse- quent experimentsshowed that anything glisteningblack and dangling, carriedby any living creaturewould releasethe very samereaction in the Jackdaws. Even Jackdawsthemselves were subjectto attack from their fellowswhen they happenedto carry nestingmaterial possessingthe char- acteristicsjust mentioned. In a bird that readily recognizesand discrimi- natesfellow-members of the flock,it is rather surprisingthat the processof releasingthe socialdefending reaction so closelyresembles that which elicitsthe responsesof lowerorganisms as alreadynoticed. An instinctivereaction of survival value, when directedexclusively to a particularobject, may be releasedas if througha surprisinglysmall choice amongthe large numberof stimuli normally emanatingfrom the object. In this circumstance,the reactionsof the highestvertebrates do not differ from those of ticks, sea-urchinsand the like. The receptorypart of the animal'sreaction responds to a small but characteristiccombination of stimuli,very muchin the way in whicha highlyselective wireless receiving- station is attuned to a particularwave-length. This perceptorycorrelate to a very definitecombination of stimuli has beentermed by William 1VIc- Dougall the 'innate perceptoryinlet.' Without knowing this author's terminology,I used the term 'angeborenesAuslSse-Schema' in German which,respecting the priorityof McDougall'sterm, I shallcompromise by translating'innate perceptorypattern.' It is an old but fitting metaphorto liken the releasingset of stimuli to the key,and the innateperceptory pattern to the lockof the instinctivere- action. Even more appropriate,is the simile of a combinationlock that cannotbe openedexcept by a definiteseries of manipulationswhich, by reasonof their generalimprobability, it is practicallyimpossible to find by chance. The relationof the particularform of the lockto the key that fits it, or of any innate perceptorypattern to the set of stimulito whichit re- sponds,is ever a compromisebetween greatest possible simplicity and 248 LorENz,The Companion in the Bird's World [July[Auk greatestpossible general improbability. The improbability of the innate perceptorypattern is to guardthe instinctivereaction from beingreleased by chancethrough other than the biologically'right' influences. Sur- prisinglysimple though the innate perceptorypatterns are in the three casescited as examples,they are evidently efficientenough, when natural conditionsare