Psychology 357, Spring 2001 (Ss 1-4, 6-9) Effect of Word Context on Letter Identification (J. C. Johnston) FIRST ANALYSIS: WORD versus NONWORD CONTEXT Six ratings: 1(different,sure),2,3,4,5,6(same,sure). Six rating probabilities: p1, .. ,p6; sum=1, for match trials. Seven cumulative probabilities: (P0=0),P1=p1,P2=p1+p2,..,(P6=1). Similarly, Q0, .. ,Q6 for mismatch trials. Pc=Pr{correct|match}=Pr{Hit}=1-P3, Qc=Pr{correct|mismatch}=Q3. Anw, Aw are estimated areas under ROC's; Diff=Aw-Anw. Bias = Pr(FA)/[Pr(FA) + Pr(Miss)] = (1-Q3)/(P3+1-Q3). DBias = Bias(Word) - Bias(Nonword). *Difference from zero is reliable. ~Difference from zero not reliable. #Difference from 500 is reliable. NONWORD-CONTEXT CONDITION (Data * 1000) Sb P1 P2 P3 P4 P5 Pc Q1 Q2 Q3 Q4 Q5 Anw Bias 1 25 125 350 525 775 650 150 475 750 875 925 755 417 2 25 50 175 475 775 825 125 350 850 950 975 863 462 3 25 150 350 500 775 650 225 600 800 900 975 802 364 4 50 125 300 500 800 700 175 525 750 900 975 786 455 6 25 75 200 325 650 800 275 675 950 950 975 906 200 7 25 100 225 325 600 775 350 725 850 975 1000 906 400 8 25 75 225 375 625 775 225 600 875 975 1000 895 357 9 25 225 450 500 575 550 325 725 875 975 1000 834 217 Mn 28 116 284 441 697 716 231 584 838 938 978 843 359# Se 3 19 33 30 33 33 29 46 24 14 9 21 35 WORD-CONTEXT CONDITION (HIGH AND LOW CONSTRAINT) (Data * 1000) Sb P1 P2 P3 P4 P5 Pc Q1 Q2 Q3 Q4 Q5 Aw Bias Diff DBias 1 50 200 300 400 625 700 325 650 825 900 975 822 368 68 -48 2 0 25 50 225 700 950 325 700 950 975 1000 971 500 107 38 3 25 75 150 350 650 850 325 750 825 975 1000 916 538 114 175 4 50 100 325 375 575 675 425 725 850 900 950 860 316 74 -139 6 0 50 125 250 575 875 350 675 950 1000 1000 958 286 52 86 7 25 100 125 175 300 875 450 850 975 975 975 939 167 33 -233 8 0 50 100 400 650 900 250 650 925 1000 1000 951 429 56 71 9 25 100 225 300 525 775 375 800 975 1000 1000 934 100 99 -117 Mn 22 88 175 309 575 825 353 725 909 966 988 919 338# 76* -21~ Se 7 19 35 30 44 35 22 25 23 15 7 18 54 10 48