fei75766_ch05_149-178.indd 167  02/06/20 11:22 AM
Chapter 5    Klein: Object Relations Theory167
Asecond assumption ofattachment theory isthatabonding relationship (or
lackthereof) becomes internalized andserves asamental working model onwhich 
future friendships andloverelationships arebuilt. Thefirstbonding attachment is
therefore themost critical ofallrelationships. However, forbonding totakeplace, 
aninfant must bemore thanamere passive receptor tothecaregiver’s behavior, 
evenifthatbehavior radiates accessibility anddependability. Attachment styleisa
relationship between twopeople andnotatraitgiven totheinfant bythecaregiver. It
isatwo-way street—the infant andthecaregiver must beresponsive toeachother and
eachmust influence theother’s behavior.
Mary Ainsworth and the Strange Situation
Mary Dinsmore Salter Ainsworth (1919–1999) wasborn inGlendale, Ohio, the
daughter ofthepresident ofanaluminum goods business. Shereceived herBA,MA,
andPhD, allfrom theUniversity ofToronto, where shealsoserved asinstructor and
lecturer. During herlongcareer, shetaught andconducted research atseveral univer -
sities andinstitutes inCanada, theUnited States, theUnited Kingdom, andUganda.
Influenced byBowlby’s theory, Ainsworth andherassociates (Ainsworth, 
Blehar, Waters, &Wall, 1978) developed atechnique formeasuring thetypeof
attachment stylethatexists between acaregiver andaninfant, known astheStrange 
Situation. Thisprocedure consists ofa20minute laboratory session inwhich apri-
mary caregiver (usually amother) andaninfant areinitially alone inaplayroom. 
Then astranger comes intotheroom, andafterafewminutes thestranger begins 
abriefinteraction withtheinfant. Then aseries ofepisodes occurs inwhich the
mother briefly leaves theroom andthenreturns. Thecritical behavior ishowthe
infant reacts when themother returns. Thisbehavior isthebasis offourattachment 
styleratings: oneknown assecure, andthree considered insecure attachment styles: 
avoidant ordismissive, anxious-ambivalent orresistant, anddisorganized.
Approximately 60%ofAmerican infants 
show asecure attachment. When theirmother 
returns, these infants arehappy andinitiate con-
tact.These infants willgoovertotheirmother 
andwant tobeheld. Allsecurely attached infants 
areconfident intheaccessibility andrespon -
siveness oftheircaregiver, andthissecurity and
dependability provide thefoundation forplay
andexploration.
Forthe15%ofAmerican infants whoare
anxious–ambivalent orresistant, theStrange 
Situation isverystressful andtheirreactions 
areambivalent. When theirmother leaves the
room, theybecome unusually upset, andwhen 
theirmother returns, theyseekcontact withher
butreject attempts atbeing soothed. With the
anxious-resistant attachment style, infants give
veryconflicted messages. Ontheonehand, they
seekcontact withtheirmother, while onthe
Mary Ainsworth JHUSheridan 
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