Psychology 357 (Experiments in Cognitive Science), Spring 2001 Some Results of the Experiment on Pattern Matching (Lab #5) (A variant of Bamber's 1969 Experiment) March 29, 2001 Data from this year (N=7; subject numbers 30 + [1-4, 6-8]) combined with data from 1996 (N=13; numbers 1-3,5-14) and 1998 (N=4; numbers 21-24) __________________ Design of the Experiment As in Bamber's (1969) experiment, there were 14 basic trial types; their frequencies among all test trials in one subject's data are: ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 SUM nrel1 24 48 NA NA NA 72 nrel2 24 24 24 NA NA 72 nrel3 36 24 24 24 NA 108 nrel4 48 24 24 24 24 144 SUM 132 120 72 48 24 396 Note that unlike Bamber's experiment, "same" responses were correct on only one third of the trials, rather than half. For all data analyses, the practice trials (first two blocks and first trial of each block) were deleted. The remaining 18 blocks are comprised of six consecutive 3-block "replication units". A replication unit is a set of trials in which all major trial types are represented with appropriate relative frequencies. Thus, in any replication unit, the 14 trial types were represented as in the following table: ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 4 8 NA NA NA nrel2 4 4 4 NA NA nrel3 6 4 4 4 NA nrel4 8 4 4 4 4 However, in another difference from Bamber's experiment, target and test string letters were in the same case (upper or lower) on half of the trials in each cell above, and were in different cases on the other half. See the lab handout for more details. Other factors manipulated within cells, and not balanced within replication units, were the position of the test string on the screen, and the location(s) within the test string of matching and mismatching letters. ________________________________________________ For all data analyses, only the last four of the six replication units were included; for most subjects, the stability of mean RT was good after the first two replication units. (Mean RTs tended to fall during the first two units, to a great extent for some subjects.) For time data, the units are milliseconds (msec) for means, and msec^2 for variances. Some of the data are reported for the seven individual subjects in our class this term. For these data, trials on which the RT exceeded 1400 msec were deleted. Most of the data are averages over 15 selected subjects from the total of 24 subjects. Subjects were excluded from this set for the following reasons: 1. Their mean RT continued to fall with practice, even after the second replication unit. (Subjects 3, 8, 14, 31, 32) 2. Their mean percent error during the last four replication units exceeded 4% (Subjects 5, 11, 21, 23) The remaining data included 264 test trials for each of 15 subjects, or a total of 3960 trials. Of these, there was one trial with RT > 2 sec; this trial (an "outlier") was deleted. ________________________________________________ Percentage Error versus condition: Case Different (Cdiff) ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 4.3 2.7 NA NA NA nrel2 6.5 2.7 1.1 NA NA nrel3 8.3 3.3 1.1 0.5 NA nrel4 8.2 10.3 2.2 2.7 1.1 Case Same (Csame) ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 6.0 1.4 NA NA NA nrel2 2.7 2.7 1.1 NA NA nrel3 3.6 9.2 2.2 2.2 NA nrel4 4.6 8.7 0.5 3.3 1.1 Mean of Cdiff, Csame ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 5.2 2.0 NA NA NA nrel2 4.6 2.7 1.1 NA NA nrel3 6.0 6.2 1.6 1.4 NA nrel4 6.4 9.5 1.4 3.0 1.1 ________________________________________________ Mean RT versus condition: , , Cdiff ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 399.1 378.7 NA NA NA nrel2 430.6 416.4 376.0 NA NA nrel3 453.4 461.8 397.3 385.3 NA nrel4 482.3 519.3 441.7 406.7 392.9 , , Csame ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 401.2 373.4 NA NA NA nrel2 425.7 416.7 369.0 NA NA nrel3 421.7 447.4 407.4 374.7 NA nrel4 449.4 499.6 447.8 405.7 394.3 Mean over Cdiff, Csame: ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 400.2 376.1 NA NA NA nrel2 428.1 416.5 372.5 NA NA nrel3 437.5 454.6 402.3 380.0 NA nrel4 465.8 509.5 444.7 406.2 393.6 Bamber's data (Csame) ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 337.3 382.0 NA NA NA nrel2 342.4 418.6 379.6 NA NA nrel3 365.1 446.6 401.1 385.7 NA nrel4 391.2 475.1 420.1 401.9 390.1 Individual data like these for this class are provided below. ________________________________________________ RT for "Different" responses as a function of the particular pattern of same (I) and different (D) letters, averaged over same and different case, and over the two assignments of hands to responses. Individual subjects and their mean. Note that for several subjects, including #31 and #36, there were no data for IDDI. For the remaining subjects, the IDDI mean was close to the ID, the DIII, and the IDDD means. For each of the subjects with missing data, the mean of that subject's ID, DIII, and IDDD was entered for IDDI. These entries are marked in the data for individual subjects in 2001 with "*". sub31 sub32 sub33 sub34 sub36 sub37 sub38 MEAN mean.15Subs D 496 409 357 395 349 403 382 398 376.0 DI 476 393 433 398 414 436 392 420 401.6 ID 489 498 453 442 480 408 435 458 434.7 DD 440 400 350 420 397 354 371 390 372.6 DII 530 491 465 416 456 370 449 454 411.2 IDI 616 432 467 544 534 412 496 500 478.8 IID 485 510 477 561 397 435 538 486 462.1 DDI 471 475 362 375 402 410 440 420 391.0 DID 412 412 394 497 380 371 377 406 391.8 IDD 614 431 444 462 419 424 416 459 424.6 DDD 498 419 391 424 379 365 366 406 380.0 DIII 490 510 450 603 484 388 399 475 434.9 IDII 709 592 570 594 550 510 509 576 523.7 IIDI 762 581 667 614 513 453 490 583 544.7 IIID 698 436 732 633 557 546 627 604 545.9 DDII 378 424 410 566 522 360 433 442 439.1 DIDI 512 450 432 538 388 412 450 455 424.0 DIID 459 442 539 852 400 375 412 497 452.0 IDDI 500* 517 414 428 474* 370 493 457 435.9 IDID 645 401 552 670 433 359 426 498 447.9 IIDD 599 827 500 499 538 433 404 543 456.7 DDDI 446 383 368 437 391 383 374 397 389.7 DDID 500 396 389 450 409 383 402 418 394.3 DIDD 464 423 442 419 408 425 446 432 411.8 IDDD 523 512 463 463 458 496 428 478 437.3 DDDD 487 391 427 405 382 371 420 412 393.6 ________________________________________________ Effects of the position of the test letter string in the test box. apos is the "absolute position" (contrasted with serial position) of the leftmost letter, where positions are numbered 1, 2, 3, and 4, from left to right. Because absolute position does not vary when nrel=4, those data are not included. , , nrel1 apos1 apos2 apos3 apos4 ndiff0 429 409 385 367 ndiff1 381 355 380 389 ndiff2 NA NA NA NA ndiff3 NA NA NA NA ndiff4 NA NA NA NA , , nrel2 apos1 apos2 apos3 apos4 ndiff0 437 405 402 NA ndiff1 401 393 421 NA ndiff2 364 383 382 NA ndiff3 NA NA NA NA ndiff4 NA NA NA NA , , nrel3 apos1 apos2 apos3 apos4 ndiff0 451 424 NA NA ndiff1 447 463 NA NA ndiff2 399 400 NA NA ndiff3 392 369 NA NA ndiff4 NA NA NA NA ________________________________________________ RT variances. Variances have much greater sampling error than means, so we can have little confidence in the values we get from such a brief, informal experiment. The values below were obtained by determining the variance of the RTs for each selected subject, for each combination of nrel, ndiff, and then determining the median of these values over the 15 subjects. , , Cdiff ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 5686 5054 NA NA NA nrel2 3653 8136 2992 NA NA nrel3 5645 11748 5111 9047 NA nrel4 7806 22755 8033 3683 2947 , , Csame ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 5872 5751 NA NA NA nrel2 5254 4325 1981 NA NA nrel3 5225 8878 9214 5093 NA nrel4 8213 13815 15169 3633 5552 ________________________________________________ Mean RT versus condition: Individual subjects this semester. , , Cdiff, sub31 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 480 464 NA NA NA nrel2 579 499 439 NA NA nrel3 562 536 460 493 NA nrel4 609 612 571 473 504 , , Csame, sub31 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 571 526 NA NA NA nrel2 516 463 441 NA NA nrel3 574 560 502 503 NA nrel4 635 646 484 491 470 , , Cdiff, sub32 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 461 421 NA NA NA nrel2 492 469 395 NA NA nrel3 531 528 465 431 NA nrel4 543 664 517 415 398 , , Csame, sub32 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 451 397 NA NA NA nrel2 524 423 405 NA NA nrel3 508 412 410 407 NA nrel4 541 449 484 430 384 , , Cdiff, sub33 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 364 349 NA NA NA nrel2 447 457 346 NA NA nrel3 497 443 387 403 NA nrel4 585 714 525 411 405 , , Csame, sub33 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 401 365 NA NA NA nrel2 374 426 354 NA NA nrel3 502 495 390 380 NA nrel4 506 498 459 408 450 , , Cdiff, sub34 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 436 404 NA NA NA nrel2 456 423 434 NA NA nrel3 524 556 403 373 NA nrel4 586 605 512 436 393 , , Csame, sub34 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 457 386 NA NA NA nrel2 438 423 405 NA NA nrel3 505 452 508 475 NA nrel4 531 616 674 451 417 , , Cdiff, sub36 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 384 343 NA NA NA nrel2 448 441 430 NA NA nrel3 463 498 414 392 NA nrel4 489 576 425 448 398 , , Csame, sub36 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 386 355 NA NA NA nrel2 458 432 364 NA NA nrel3 460 436 379 367 NA nrel4 418 466 483 390 367 , , Cdiff, sub37 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 452 396 NA NA NA nrel2 457 411 354 NA NA nrel3 451 394 380 365 NA nrel4 460 443 383 406 37 0, , Csame, sub37 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 395 409 NA NA NA nrel2 407 433 354 NA NA nrel3 409 432 423 366 NA nrel4 442 485 395 414 372 , , Cdiff, sub38 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 353 373 NA NA NA nrel2 414 442 373 NA NA nrel3 457 509 420 364 NA nrel4 455 478 442 400 448 , , Csame, sub38 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 386 390 NA NA NA nrel2 368 391 370 NA NA nrel3 397 484 393 368 NA nrel4 441 557 427 425 392 ________________________________________________ The same, means over Csame and Cdiff: , , sub31 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 525 495 NA NA NA nrel2 547 481 440 NA NA nrel3 568 548 481 498 NA nrel4 622 629 527 482 487 , , sub32 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 456 409 NA NA NA nrel2 508 446 400 NA NA nrel3 520 470 438 419 NA nrel4 542 557 500 423 391 , , sub33 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 383 357 NA NA NA nrel2 411 441 350 NA NA nrel3 499 469 388 391 NA nrel4 546 606 492 410 427 , , sub34 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 447 395 NA NA NA nrel2 447 423 419 NA NA nrel3 514 504 456 424 NA nrel4 559 611 593 443 405 , , sub36 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 385 349 NA NA NA nrel2 453 436 397 NA NA nrel3 462 467 397 379 NA nrel4 454 521 454 419 382 , , sub37 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 424 403 NA NA NA nrel2 432 422 354 NA NA nrel3 430 413 402 365 NA nrel4 451 464 389 410 371 , , sub38 ndiff0 ndiff1 ndiff2 ndiff3 ndiff4 nrel1 370 382 NA NA NA nrel2 391 416 371 NA NA nrel3 427 497 406 366 NA nrel4 448 517 435 412 420