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effet du nombre des graphèmes en Anglais - Aix Marseille Université

effet du nombre des graphèmes en Anglais - Aix Marseille Université

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App<strong>en</strong>dice III 259qu<strong>en</strong>cy condition, the target letter was embedded into a multi-letter grapheme. For the other list of words, thetarget letter had the status of a single-letter grapheme. That is, as an example, let A be the target letter. Thefour words in each experim<strong>en</strong>tal condition were : 1. HOARD in the low frequ<strong>en</strong>cy - multi-letter graphemecondition ; 2. BRASH in the low frequ<strong>en</strong>cy - single-letter grapheme condition ; 3. BOARD in the high frequ<strong>en</strong>cy- multi-letter grapheme condition ; 4. STAFF in the high frequ<strong>en</strong>cy - single-letter grapheme condition.The mean frequ<strong>en</strong>cy values of each word list was respectively : 5.1, 5.1, 138.7 and 139.8 (occur<strong>en</strong>ces permillion). The experim<strong>en</strong>t was controlled by a Macintosh SE computer. The stimuli were typed with fontCourrier size 24.Proce<strong>du</strong>reParticipants were seated at 50 cm in front of the computer scre<strong>en</strong> and were giv<strong>en</strong> writt<strong>en</strong> instructions.They started with a training session composed of 10 trial (5 target-pres<strong>en</strong>t and 5 target-abs<strong>en</strong>t trials). After abreak <strong>du</strong>ring which any questions concerning the task were answered, the experim<strong>en</strong>t started with the 120experim<strong>en</strong>tal trials (60 target-pres<strong>en</strong>t and 60 target-abs<strong>en</strong>t) pres<strong>en</strong>ted in a randomized order for each participant.Each trial began with a 700 ms pres<strong>en</strong>tation of the target letter in the middle of the scre<strong>en</strong>. Th<strong>en</strong> a fixationmark (« : ») was pres<strong>en</strong>ted for 1000 ms. The fixation mark was replaced by the stimulus word, which remainedon the scre<strong>en</strong> for 33 ms. The stimulus word was followed by a blank that was pres<strong>en</strong>ted for 70 ms.Th<strong>en</strong> a mask consisting of superimposed X’s and O’s, appeared on the scre<strong>en</strong> until participant’s response.Afterward, the mask was replaced by a blank for 1000 ms that was followed by the next trial. The target letterwas pres<strong>en</strong>ted in uppercase and the stimulus word in lowercase. The <strong>en</strong>tire proce<strong>du</strong>re took about 15 minutes tocomplete.RESULTSMean correct response times and error rates for the four experim<strong>en</strong>tal conditions are reported in Table 1(upper panel). The trimming proce<strong>du</strong>re excluded scores smaller than 200 ms and greater than 3 SDs above theparticipant’s overall response time. Analyses of variance (ANOVAs) were con<strong>du</strong>cted using both participants(F 1 ) and items (F 2 ) as random factors, treating frequ<strong>en</strong>cy and grapheme category as within-participant factors.Response times were affected by the grapheme manipulation but not by word frequ<strong>en</strong>cy. Letter detectiontimes were longer for letters embedded in a multi-letter grapheme compared to letters having the status ofsingle-letter graphemes, F1(1,20) = 7.38, p < .05 ; F2(1,56) = 4.21, p < .05. No differ<strong>en</strong>ce was observedbetwe<strong>en</strong> the high and low frequ<strong>en</strong>cy conditions, all Fs < 1. The error data did not show any effect of graphemecategory or word frequ<strong>en</strong>cy, all Fs < 1.EXPERIMENT 2ParticipantsParticipants were 19 stud<strong>en</strong>ts from the C<strong>en</strong>ter for Cognitive Neurosci<strong>en</strong>ce. All were native Fr<strong>en</strong>ch speakersand had normal or corrected to normal vision.Stimuli and ApparatusThe stimulus set was elaborated in the same way as in Experim<strong>en</strong>t 1 except that word stimuli were monosyllabic,5-letter Fr<strong>en</strong>ch words. Frequ<strong>en</strong>cy was estimated using the BRULEX frequ<strong>en</strong>cy count (Cont<strong>en</strong>t,Mousty, & Radeau, 1990). Low-frequ<strong>en</strong>cy words had less than 10 occur<strong>en</strong>ces per million and high-frequ<strong>en</strong>cywords had more than 50 occur<strong>en</strong>ces per million. As an example, let A be the target letter. The four words ineach experim<strong>en</strong>tal condition were : 1. TAUPE in the low frequ<strong>en</strong>cy - multi-letter grapheme condition ; 2.BAGNE in the low frequ<strong>en</strong>cy - single-letter grapheme condition ; 3. CAUSE in the high frequ<strong>en</strong>cy - multilettergrapheme condition ; 4. SALLE in the high frequ<strong>en</strong>cy - single-letter grapheme condition. The meanfrequ<strong>en</strong>cy values of each word list was respectively : 4, 4, 95.5 and 88.5 (occur<strong>en</strong>ces per million). The experim<strong>en</strong>twas controlled by a Macintosh Quadra computer.Proce<strong>du</strong>reThe experim<strong>en</strong>tal proce<strong>du</strong>re was the same as in Experim<strong>en</strong>t 1.RESULTSMean correct response times and error rates for the four experim<strong>en</strong>tal conditions are reported in Table 1(lower panel). The trimming proce<strong>du</strong>re excluded scores smaller than 200 ms and greater than 3 SDs above theparticipant’s overall response time. Analyses of variance (ANOVAs) were con<strong>du</strong>cted using both participants(F 1 ) and items (F 2 ) as random factors, treating frequ<strong>en</strong>cy and grapheme category as within-participant factors.As in Experim<strong>en</strong>t 1, response times were affected by the grapheme manipulation but not by word frequ<strong>en</strong>cy.Letter detection times were longer for letters embedded in a multi-letter grapheme compared to lettershaving the status of single-letter graphemes, F1(1,18) = 27.75, p < .0001 ; F2(1,56) = 4.53, p < .05. Nodiffer<strong>en</strong>ce was observed betwe<strong>en</strong> the high and low frequ<strong>en</strong>cy conditions, all Fs < 1. The error data showed amarginal effect of grapheme category, that is, subjects did more errors in detecting a letter into a multi-letter

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