Further evidence for a unified store comes from experiments involving continual distractor tasks. In 1974, Bjork and Whitten presented subjects with word pairs to remember; before and after each word pair, subjects performed a simple multiplication task for 12 seconds. After the final word-pair, subjects performed the multiplication distractor task for 20 seconds. They reported that the recency effect (the increased probability of recall of the last items studied) and the primacy effect (the increased probability of recall of the first few items) was sustained. These results are incompatible with a separate short-term memory as the distractor items should have displaced some of the word-pairs in the buffer, thereby weakening the associated strength of the items in long-term memory.
fuRTher eViDENce for a uniFied sToRe comEs from ExPerIMeNTS iNvOLving cOntiNuaL Distractor taSkS. iN 1974, BjOrk anD WHitten pResenTed subjecTs With Word paIrS to ReMembeR; befoRe aND aFteR Each worD paIR, SubjEcts peRforMEd A sImPle mUltIPlicaTion task for 12 secOnDs. afTeR THe fInAL woRd-pAir, subjects pERForMed ThE mulTIplication DistrActoR TASk fOR 20 seconds. they REPortED that tHe rECencY Effect (the inCreased probAbility Of ReCALl of the last itemS sTUdied) anD thE pRimacy effect (tHe Increased PRObabilITY of RecaLl of thE firSt feW ItemS) was SUStAiNeD. tHesE reSulTS are inCOmpaTiBle with a sEparatE shOrt-Term mEmory As The DistRactOr items Should have displaced sOMe of the Word-paiRs In tHe buFFer, ThEreby Weakening the assocIaTeD strEngtH of The iteMs In LoNG-teRm MemOry.