Letter Perception Experiment: Stimulus Materials The test trials made use of 80 sets of four 4-letter strings (80 quadruples), the first two being words, the second two being matched nonwords. The two members of each pair differ by one letter (the same critical letter for the word-pair and the nonword-pair). The position of the critical letter can be 1,2,3, or 4; there are 20 quadruples with each position. The quadruples in each set of 20 are arranged in pairs with the same critical letters; let's call the two quadruples with the same critical letters an octuple. The quadruples in each octuple differ in the constraint that the other letters in the words place on the critical letter. The members of each pair have adjacent quadruple numbers, the low-constraint member having an odd number, n, the high-constraint member having number n+1. Constraint level is indicated in the last column of the table. In the course of the experiment, each quadruple is used twice for a subject, one or both of the words being used once, one or both of the nonwords once. The sixth column in the table gives the position of the critical letter. Note that because of characteristics of four-letter words, together with nonword-word matching requirements, the critical letter in the second position for nonwords is, in most cases, a vowel, which may increase the pronounceability of the nonword, relative to those with critical letters in other positions. --------------------------------------------------------------------- Quad Word1 Word2 Nonwd1 Nonwd2 Pstn Cnstrnt 1 WINK SINK WDNK SDNK 1 low 2 SHIP WHIP SHDP WHDP 1 high 3 SELL HELL STLL HTLL 1 low 4 HEWN SEWN HCWN SCWN 1 high 5 GAME DATE GMTL DMTL 1 low 6 DRIP GRIP DRNP GRNP 1 high 7 RAMP DAMP RFMP DFMP 1 low 8 DISK RISK DNSK RNSK 1 high 9 GONE BONE GDNC BDNC 1 low 10 BOAT GOAT BMCT GMCT 1 high 11 TILL JILL TMLL JMLL 1 low 12 JUNE TUNE JLNV TLNV 1 high 13 TUCK BUCK TLCK BLCK 1 low 14 BEAM TEAM BLCM TLCM 1 high 15 PANE DANE PMNS DMNS 1 low 16 DECK PECK DMCK PMCK 1 high 17 DENT CENT DBNT CBNT 1 low 18 CRAG DRAG CRLT DRLT 1 high 19 LOOT FOOT LSWT FSWT 1 low 20 FIST LIST FHST LHST 1 high 21 HILL HALL LILH LALH 2 low 22 DART DIRT RADT RIDT 2 high 23 LOST LAST SOST SAST 2 low 24 CAST COST TASC TOSC 2 high 25 MILL MALL LIML LAML 2 low 26 MANE MINE NAMG NIMG 2 high 27 FOND FIND NOFR NIFR 2 low 28 NINE NONE NIND NOND 2 high 29 DUCK DOCK KUCD KOCD 2 low 30 MOCK MUCK KOCM KUCM 2 high 31 MOST MIST TOJS TIJS 2 low 32 LIVE LOVE MIVT MOVT 2 high 33 LICK LACK KICL KACL 2 low 34 LACE LICE CALB CILB 2 high 35 MISS MESS SISM SESM 2 low 36 MEND MIND DEMN DIMN 2 high 37 BOLL BELL LOLB LELB 2 low 38 BELT BOLT LETB LOTB 2 high 39 SLOW SHOW SLFW SHFW 2 low 40 SHED SLED SHFD SLFD 2 high 41 SANE SALE SFNP SFLP 3 low 42 HILT HINT HGLT HGNT 3 high 43 FARE FAKE FDRL FDKL 3 low 44 POKE PORE PDKL PDRL 3 high 45 LAVE LAME LHVR LHMR 3 low 46 NAME NAVE NSMT NSVT 3 high 47 DINE DICE DFNR DFCR 3 low 48 TACK TANK TLCK TLNK 3 high 49 GAME GALE GCMT GCLT 3 low 50 HELP HEMP HSLP HSMP 3 high 51 WARE WANE WBRD WBND 3 low 52 HUNT HURT HDNT HDRT 3 high 53 LOSE LONE LCSP LCNP 3 low 54 PENT PEST PCNH PCSH 3 high 55 NOTE NOSE HBTR NBSR 3 low 56 MASH MATH MRSH MRTH 3 high 57 RARE RACE RSRL RSCL 3 low 58 PACT PART PMCT PMRT 3 high 59 MINE MILE MHNR MHLR 3 low 60 MILK MINK MFLK MFNK 3 high 61 LEAP LEAF LSNP LSNF 4 low 62 GULF GULP GTLF GTLP 4 high 63 DEAN DEAL DFKN DFKL 4 low 64 MEAL MEAN MFKL MFKN 4 high 65 HARP HARM HLRP HLRM 4 low 66 STEM STEP STLM STLP 4 high 67 FORK FORM FDRK FDRM 4 low 68 LOOM LOOK LDCM LDCK 4 high 69 CART CARE CGRT CGRE 4 low 70 POSE POST PGSE PGST 4 high 71 BEAN BEAD BWRN BWRD 4 low 72 RAID RAIN RWHD RWHN 4 high 73 SEEP SEEN SLTP SLTN 4 low 74 CHIN CHIP CHLN CHLP 4 high 75 CLAW CLAP CLNW CLNP 4 low 76 CROP CROW CRNP CRNW 4 high 77 SLIP SLIM SLRP SLRM 4 low 78 TRIM TRIP TRCM TRCP 4 high 79 HEAR HEAL HMNR HMNL 4 low 80 FOUL FOUR FMNL FMNR 4 high