Rudy, K ra u te r and G a ffu r i (1976, Experiments 3 and 4) found th a t sim ple p re s e n ta tio n o f another n e u tra l s tim u lu s , p r io r to pre-exposure o f th e CS, le d to fa s te r c o n d itio n in g w ith CS— >shock t r i a l s .
T his a tte n u a tio n o f the CS pre-exposure e ffe c t, by p r io r exposure to another s tim u lu s , is o p p o site to what would be expected w ith sim ple
stim u lu s g e n e ra liz a tio n . S tim ulus g e n e ra liz a tio n would suggest th a t the e x te n t to w hich the two CSs a re tre a te d id e n t ic a lly , p re s e n ta tio n o f one CS should increase th e CS pre-exposure e ffe c t to th e o th e r. Rudy suggest e xp la n a tio n s in terms o f storage o r r e tr ie v a l f a ilu r e , ro u g h ly as fo llo w s : F ir s t , th a t memory o f the f i r s t stim u lu s (S I) has a d e trim e n ta l e ffe c t on storage o f th e memory o f the second s tim u lu s (S 2), perhaps by p ro a c tiv e in te rfe re n c e ; thus SI p re s e n ta tio n s had the e ffe c t th a t ” S2 p re s e n ta tio n s were not processed in a way w hich allow ed f o r storage o f i t s re p re s e n ta tio n in memory." (Rudy ja l, p243). Second, th e re could be r e tr ie v a l f a ilu r e : "SI in te rfe re d w ith the a b i l i t y o f Sc ( ie , the co n te xt - ID ) to r e tr ie v e a re p re s e n ta tio n o f S2 a t th e tim e o f the c o n d itio n in g episode" (p243).
To me, both these e xp la n a tio n s are guesses w ith l i t t l e backing from o th e r experim ents, o r th e o re tic a l sources. T his is understandable, given hew s u rp ris in g th is r e s u lt is ! T his r e s u lt goes a g a in s t th e b a sic a s s o c ia tiv e approach. Even th e c o g n itiv e idea o f 'le a rn in g th a t events occur in is o la tio n ' is unable to h e lp , as i t p re d ic ts th a t unpaired p re s e n ta tio n s o f another CS should in crea se the CS pre-exposure ^ f e c t . So, ra th e r d is tu r b in g ly , none o f the th e o rie s can accommodate th e Rudy f i t a l r e s u lt w ith o u t adding f a i r l y a r b itr a r y assum ptions.
Ilfi PRE-EXPOSURE
Seligman, M aier, Jackson and others have s tu d ie d a phenomenon they termed 'Learned H elplessness' in w hich humans and o th e r mammals
have been given p a in fu l o r o th e rw ise u n d e sira b le experiences p r io r to a le a rn in g ta s k ; they have accumulated a la rg e body o f data on th e US pre-exposure e ffe c t, u s in g procedures n o t n o rm a lly employed in the anim al le a rn in g paradigm. I s h a ll discuss t h e ir anim al work a fte r the
's ta n d a rd ' US pre-exposure e ffe c t.