Stroop manuscript_29
Transcription
Stroop manuscript_29
Dean & Klein!Font Effect page 1 of 28 Dean & Klein!Font Effect Dean, C. T. & Klein, R. M. (2010, February) In search of the font effect: The effect of conflict upon reading and naming typefaces serially, Paper presented at the 4th International Conference on Design Principles and Practices (Chicago, USA) and manuscript submitted for publication in Design Principles and Practices: An International Journal. In search of the Font Effect: the effect of conflict upon reading and naming typefaces serially. Christopher T. Dean, NSCAD University typographer@gmail.com Raymond M. Klein, Dalhousie University ray.klein@dal.ca page 1 of 28 Dean & Klein!Font Effect Abstract Stroop (1935) demonstrated that conflicting words interfered with ink colour naming while conflicting colours did not interfere with word reading. In our study — a collaboration between a typographer and a psychologist — we re-created Stroop's study by replacing colour names with typeface names, ink colours with typefaces, and control colour squares with a pseudoword. Relatively expert participants who could recognize the five typefaces (Helvetica, Times, Papyrus, Garamond and Ondine) were asked to read and name the typefaces from a 10 × 10 matrix, modeled after Stroop’s original materials, with and without conflict. (Typographer:) “Despite the specialized skill for typeface recognition in our participants” we replicated Stroop’s finding of asymmetrical interference, (psychologist:) “confirming the dominance of reading.” page 2 of 28 Dean & Klein!Font Effect In 1935 John Ridley Stroop published an article titled “Studies of verbal interference in serial verbal reactions.” This article has been cited 4,435 times1 and continues to be one of the most famous experiments in the history of cognitive psychology. As reported by MacLeod (1991), at least 700 Stroop related articles have been written on this phenomenon between its original publication and 1991. Figure 1 illustrates the number of Stroop citations by decade since its original publication and 2004. ! Stroop’s original study consisted of three separate experiments. The results of the first two, which our study combined into a single experiment, can be summarized as follows: Stroop’s (1935) Experiment 1 was a reading task. It required participants to read colour names printed in conflicting as well as neutral ink colours. It showed no significant difference in Number of citations 2,000 1,500 1,000 500 0 1935-1944 1945-1954 1955-1964 1965-1974 1975-1984 1985-1994 1995-2004 Decade since publication Figure 1. Number of citations of Stroop (1935) by decade since publication. 1. ISI Web of Science database as of 10 August, 2008. page 3 of 28 Dean & Klein!Font Effect faratime between the two. Stroop’s (1935) Experiment 2 was a naming task. Participants were required to name ink colours in which conflicting colour names were spelled (for example when presented with the colour name red printed in green ink the correct response would be to say “green”) as well as coloured squares. It showed that it took significantly longer to name the ink colours in which conflicting colour names were spelled than it did to name the ink colours of the coloured squares. See Figures 2–42 for photographs of some of Stroop’s original materials. ! 2. Courtesy of Colin M. MacLeod, Professor of Psychology, University of Waterloo. Digital image colour correction courtesy of Marilyn S. Klein, Dentistry Instructional Resources, Dalhousie University. page 4 of 28 Dean & Klein!Font Effect Figure 2: Stroop’s (1935) original materials — conflict reading/naming page 5 of 28 Dean & Klein!Font Effect Figure 3: Stroop’s (1935) original materials — control naming page 6 of 28 Dean & Klein!Font Effect Figure 4: Stroop’s (1935) original materials from a display case at the Peabody College of Vanderbilt University (Nashville, Tennessee). ! These patterns of results, which has been replicated many times (see Table 1 for Stroop’s results and a close replication), indicate that the presence of conflict does not interfere with reading, but does interfere with naming and that consequently reading is a dominant response to colour naming. The interference effect, as seen specifically in Stroop’s (1935) Experiment 2 (bottom two rows of Table 1), page 7 of 28 Dean & Klein!Font Effect has since been referred to as “Stroop interference” or “the Stroop effect.” ! Experts in the fields of typography, type design and graphic design, are capable of rapidly identifying many typefaces, often when presented with only a few characters. This capacity for typeface recognition can become almost as easy to them as naming colours is to the lay-person. The typeface aficionado, like the first author of this paper, may even have a hyper-sensitivity and attentional bias with regard to typefaces. It is virtually impossible for such a skilled typographer to determine what is on the menu and how much it costs without first inspecting the typeface. ! The purpose of this study, which resulted from a collaboration between a typographer and a cognitive psychologist each learning about the other’s field of expertise, is to extend the Stroop effect with color naming to the naming of typefaces. Table 1: Mean times in seconds for reading and naming in conflict and no-conflict conditions for Stroop (1935) and MacLeod (1986) as cited in MacLeod (1991). Stroop (1935) MacLeod (1986) Reading with conflict 43.3 41.58 Reading without conflict 41.0 41.16 Naming with conflict 110.3 102.27 Naming without conflict 63.3 59.76 page 8 of 28 Dean & Klein!Font Effect Modeled on Stroop (1935), in this study we will replace the names of colours with the names of typefaces, ink colours with typefaces and control colour squares with a control pseudoword3 . Instead of reading colour names and naming ink colours, participants in this study were asked to read typeface names and name typefaces in conflicting and non-conflicting conditions. Table 2 illustrates various combinations of tasks, conditions and correct responses used in Stroop’s (1935) and in this study. ! Because reading is a dominant response we both expected that we would replicate Stroop’s finding from the naming condition: Conflicting typeface words should interfere with the task of naming the typeface in which these words were printed. With regard to the reading task, however, the two authors generated different hypotheses; Table 2. Stimuli and correct responses in the different conditions of Stroop's classic experiment and the present one. Stroop (1935) Dean and Klein (2008) Stimuli Stimuli Correct response Correct response Reading without conflict Green “Green” Helvetica “Helvetica” Reading with conflict Green “Green” Helvetica “Helvetica” “Green” Egrubma “Helvetica” “Red” Helvetica “Garamond” Naming without conflict Naming with conflict Green 3. The pseudoword “Egrubma” — a portion of the pseudoword “Hamburgerfons” spelled backwards — was used in this study. “Hamburgerfons” is a pseudoword commonly used by typographers, type designers and graphic designers in which they set a typeface in order to ascertain its unique characteristics. The pseudoword “Hamburgerfons” was shortened because it was longer than all of the typeface names used in this study. The order of the letters were reversed to generate a novel yet pronounceable pseudoword. page 9 of 28 Dean & Klein!Font Effect ! The psychologist hypothesized that typeface names, even for experts, would have the same status as do colour names for typical Stroop participants (they are well-known but speeded naming of them would not be a dominant response), and consequently that there should be no interference when reading typeface names from the conflicting typeface in which the words were printed. The typographer, however, hypothesized that when reading typeface names, the participants who were skilled in typeface recognition would experience interference from the conflicting typefaces in which these words were printed. If observed, he would have called this “The Font Effect.” page 10 of 28 Dean & Klein!Font Effect Method Participants ! Eleven participants (six males and five females whose ages ranged from 22–58 years, mean = 37.523, SD = 12.846) were recruited from faculty, students and alumni of NSCAD University and Dalhousie University during various presentations and teaching sessions on typography. Their level of education ranged from third year undergraduate to third year graduate. Professional experience ranged from none to 20 years. All had previous training in the arts, graphic design and/or typography. All participants reported normal or corrected to normal vision and spoke English as a first language. One participant was bilingual, fluent in English and French. Participants received $8.00 Canadian as compensation. All participants were treated in accordance with the Tri-Council Policy Statement’s of Ethical Conduct for Research Involving Humans. page 11 of 28 Dean & Klein!Font Effect Apparatus and stimuli ! Eight black and white pages of 36 × 24 in. (91.44 × 60.96 cm) were used as stimuli in this experiment: Stimulus page 1 (CN1) — Typeface names printed in conflicting typefaces: On this page five typeface names (Courier, Garamond, Helvetica, Ondine and Papyrus) were printed in one of five different typefaces (ITC Courier Medium, ITC Garamond Regular, Helvetica Neue 55 Roman, Adobe Ondine Regular and Adobe Papyrus Regular)4 . Each page had the words laid out so that there were 10 words per line and a total of 10 lines. The five typefaces used in this experiment were selected based upon their lack of confusability with one another and ease of pronunciation (see Appendix A: The card sorting task). Once an arbitrary mapping rule was chosen, the ordering of the words and typefaces corresponded exactly with the ordering of words and colours used in Stroop’s original materials (see figures 2-4), but not exactly with his description of how he arrived at this ordering5. 4. For a complete description of the methodology used to select these five typefaces see Appendix A. 5. Quoting Stroop (1935) “The words were also arranged so that the name of each color would appear twice in each line. No word was printed in the color it named but an equal number of times in each of the other four colors.” However, in figure 2 you can clearly see that the word brown appears three times in the first column. Additionally, you can see three brown control patches in the last column of figure 3.. page 12 of 28 Dean & Klein!Font Effect ! The size of each word was adjusted so that they shared a common x-height of 20 postscript points (pts, 7.056 mm). Words were horizontally separated from one another with five en6 spaces of Helvetica Neue 55 Roman at 40.63 pts (14.333 mm). Inter-liner spacing was set to 117.61 pts (49.410 mm), tracking was set to zero and kerning was set to automatic. An additional practice row of 10 words appeared at the top of each page separated vertically from the rest of the words by 235.22 pts (82.980 mm). Top, left/right and bottom margins were 2.3 in. (58.420 mm), 1.8 in. (45.720 mm) and 3.2 in. (81.280 mm) respectively. The task for this page was to name the typefaces. Figure 5 illustrates this stimulus page. Stimulus page 2 (CN2) — Typeface names printed in conflicting typefaces: This page was similar to CN1 except the orders of the words and typefaces were reversed both horizontally and vertically. The task for this page was to name the typefaces. 6. A unit of measurement equal to half of the typesize in use. page 13 of 28 Dean & Klein!Font Effect Figure 5: A sample stimulus page illustrating a condition of conflict (scaled to 18%). Stimulus page 3 (CR1) — Typeface names printed in conflicting typefaces: This page was physically identical to CN1. The difference was that the task for this page was to read the words. Stimulus page 4 (CR2) — Typeface names printed in conflicting typefaces: This page was physically identical to CN2. The difference was that the task for this page was to read the words. page 14 of 28 Dean & Klein!Font Effect Stimulus page 5 (N1) — Control pseudoword printed in a nonconflicting typeface: On this page, instead of the name of a typeface, the pseudoword, Egrubma, appeared laid out following the same specifications of CN1. The task for this page was to name the font. Stimulus page 6 (N2) — Control pseudowords printed in nonconflicting typefaces: This page was similar to N1 except the order of the typefaces was reversed both horizontally and vertically. The task for this page was to name the typefaces. Stimulus page 7 (R1) — Typeface names printed in nonconflicting typefaces: This page was similar to page CN1 except the font names were set in Linotype Univers 530. The task for this page was to read the words. Stimulus page 8 (R2) — Typeface names printed in nonconflicting typefaces: This page was similar to R1 except the order of the words were reversed both horizontally and vertically. The task for this page was to read the words. page 15 of 28 Dean & Klein!Font Effect ! A 36 × 24 in. (91.44 × 60.96 cm) sheet of 3∕16 in. (4.763 mm) Bainbridge All Black Foamboard was used as a shield to cover the pages preventing participants from seeing them until it was appropriate for them to do so. ! The stimulus pages were produced on a MacBook Pro, model identifier: MacBookPro2,2 with a 15 in. (38.1 cm) display at a native resolution of 1440 × 900 pixels set to millions of colours, a 2.33 GHz Intel Core 2 Duo processor, 2 GB of RAM and a 210 GB hard drive running Mac OS X version 10.4.11. Software used to produce the pages was Adobe Illustrator CS version 11.0.0. Files were saved as Adobe Acrobat PDF’s with no downsampling or compression saved with version 4.0 compatibility. Pages were printed by an Océ TDS 450 printer at 600 dots per inch (DPI) on white 24 lb Océ bond paper and laminated by a GBC Discovery 80 laminator with a 3 mil matte lamination. The luminance of the stimulus pages varied from approximately 20–25 candelas per meter squared (cd/m2). ! For each of the previously described pages, there was a corresponding 8.5 × 11 in. (21.59 × 27.94 cm) score sheet for use by the experimenter to identify any errors the participants might make while naming or reading. On each score sheet were printed the words Courier, Garamond, Helvetica, Ondine and page 16 of 28 Dean & Klein!Font Effect Papyrus in a 10 × 10 matrix corresponding with the correct responses for each of the afore mentioned stimulus pages. The specimen sheets This six page document measured 8.5 × 11 in. (21.59 × 27.94 cm) consisted of five different specimen sheets, one for each of the five typefaces used in the experiment, followed by a small naming exercise. Each specimen sheet contained a complete alphabet of both uppercase and lowercase letters, numerals and selected glyphs such as a dagger, ligature and ampersand. Typefaces for each specimen sheet were set at 42 pts (14.817 mm) with an inter-linear spacing 52 pts (18.344 mm). Due to differences in the proportional spacing of each typeface, tracking was adjusted so that each specimen sheet shared the same number of letters per line. Each page also contained two small passages of lorem ipsum7. The first passage was set at 10 pts (3.528 mm) with an inter-linear spacing of 12 pts (4.233 mm) and a line length of 264 pts (93.133 mm). The second passage was set at 12 pts (4.233 mm) with an interlinear spacing of 14 pts (4.939 mm) and a line length of 264 pts (93.133 mm). Figure 6 illustrates a page from this document. 7 Lorem ipsum is placeholder text often used by typographers to illustrate how actual text will appear on a page. It is used because it resembles normal letter distribution in the English language as opposed to random letter strings. page 17 of 28 Dean & Klein!Font Effect Ondine abcdefghijklmnop qrstuvwxyz ABCDEFGHIJKLMM NOPQRSTUVWXYZ 1234567890 !@#$%^&* { [ ( fi fl † ‡ § ¶ ‘ “ , … ) ] } 10 /12 Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent 12/14 Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua autem. Duis autem vel eum iriure dolor in Figure 6: A page from the specimen sheets booklet. page 18 of 28 Dean & Klein!Font Effect ! Participants were timed with a Nexxtech digital stopwatch, model number 6315022, accurate to one hundredth of a second. Data was collected, analyzed and presented using Numbers ‘08 version 1.0.2, pro Fit version 6.1.8 and Adobe Illustrator CS3 version 13.0.2. Luminance was measured8 with a UDT Technology photometer model number 161 calibrated by the National Science Laboratory in Washington DC. 8. Courtesy of Dr. Donald E. Mitchell, Professor Emeritus, Department of Psychology, Dalhousie University. page 19 of 28 Dean & Klein!Font Effect Design Each participant was exposed to four of the eight pages. The assignment of pages to conditions was accomplished by a factorial combination of the two tasks (naming and reading), the two page types (conflict and no-conflict) and the two orders (the same pages previously mentioned with the orders of the rows and columns reversed). In order to avoid switching between tasks (and hence to minimize the difficulty of the tests) the two conditions (conflict and no-conflict) of each task (reading and naming) appeared in successive pairs. The eight participant sample condition and the order of tasks were fully counterbalanced across the eight blocks to remove any untoward effects of order. Procedure In order to ensure that participants were capable of naming the typefaces, which would allow us to measure the effects of interference, they were provided with the specimen sheet document for review least 24 hours prior to the experiment. Before the experiment began participants were informed about the tasks they were about to perform and gave their written consent. Participants entered a 3 × 3 × 2.5 yard (2.743 × 2.743 × 2.286 m) room and were seated in a chair 18 in. (45.720 cm) high at a page 20 of 28 Dean & Klein!Font Effect 30 × 36 × 22 in. (76.200 × 91.440 × 55.880 cm) table at an angle of 180°. The room was lit by three individually mounted 100 watt tungsten light bulbs covered with translucent shades. Each participant entered the experimental room at least three minutes prior to beginning the experiment in order to allow their eyes to adjust to the lighting conditions. Figure 7 shows the experiment room with the experimenter on the left and a pilot participant on the right. ! Figure 7: The experimenter (typographer) running a pilot participant (psychologist) in the experimental room. page 21 of 28 Dean & Klein!Font Effect Participants were assigned to one of the eight different orders of the eight conditions as seen in table 3. ! Each session began with a stack of four pages placed face up on the table. Each page was held in place by a small piece of packaging tape and the stack was covered by the foamcore shield. Before the shield was removed, participants were informed of the requirements of the upcoming test. They were instructed to either read the words or name the typefaces. They were instructed to go as quickly as possible without making mistakes and, following Stroop’s original instructions, to correct any mistakes that they noticed they had made. They were encouraged to follow along with their finger to avoid losing their place. Each condition began with a single 10 word practice line followed by the remainder of the page which consisted of 10 lines of 10 items of 100 items. Table 3: Condition orders for the eight participants used in this study. Ss1: CR1 R2 CN2 N1 Ss2: CN1 N2 CR2 R1 Ss3: R1 CR2 N1 CN2 Ss4: N1 CN2 R1 CR2 Ss5: R2 R1 CN1 N2 Ss6: N2 N1 CR1 R2 page 22 of 28 Dean & Klein!Font Effect The practice On the signal “Ready! Go!” — the same signal used by Stroop in 1935 — the experimenter started timing and the participant moved the shield approximately 5 in. (12.7 cm) downwards exposing the 10 item practice row at the top of the page. Participants then performed the practice task while the experimenter followed along the corresponding check sheet and kept track of any errors the participant made. Upon completion of the practice participants were informed of any mistakes they had made. The test On the signal “Ready! Go!” the experimenter started timing and the participant removed the shield exposing the rest of the page. Participants then performed the test while the experimenter followed along the corresponding score sheet to keep track of any errors. Upon completion of each condition, participants were informed of any mistakes they had made. ! This process was repeated for each of the four conditions. After the experiment was complete participants were told about the nature or the original Stroop experiment and the aim of this study. After this debriefing, any questions were answered and participants were compensated for their participation. page 23 of 28 Dean & Klein!Font Effect Results ! Mean time to read pages in the no-conflict condition was 57.010 seconds (SD = 8.009). On average, participants took 1.566 seconds longer to read the typeface names in a conflict condition than they did in a no-conflict condition (SE = 1.994). A paired t-test indicated that this difference (representing, on average, about 16 ms per item) was not significant (t(10) = 0.749, p = 0.471). ! Mean time to name typefaces in a no-conflict condition was 123.473 seconds (SD = 20.630). On average, participants took 30.220 seconds longer to name typefaces in a conflict condition than they did in a no-conflict condition (SE = 7.350). A paired t-test indicated that this difference (representing an interference effect from the conflicting typeface names upon typeface identification times of about 300 ms per item) was significant (t(10) = 3.920, p = 0.003). page 24 of 28 Dean & Klein!Font Effect Discussion The results of this experiment showed the following: a) No significant difference in reading time between conditions of conflict and no-conflict. b) Participants took significantly longer to name typefaces in conditions of conflict than they did in conditions of nonconflict. ! These findings are consistent with Stroop (1935) and MacLeod (1991). They extend the finding of the Stroop effect from naming colours to naming fonts and show that even for individuals who are skilled at recognizing typefaces9 , reading still presents itself as a dominant response to naming as first observed by John Ridley Stroop in 1935. So, is the Font Effect a figment of the typographer's imagination or does it simply remain to be discovered? In the future, the typographer would like to test type designers specifically, as he hypothesizes that they would have an even greater sensitivity towards typeface recognition thereby increasing the chances for typeface interference. 9 Including the primary author of this paper who has spent over 20 years investigating various aspects of typography and typographic specimens, and freely admits that he spends very little time reading compared to the layperson. page 25 of 28 Dean & Klein!Font Effect References MacLeod, C. M. (1991). Half a century of research on the Stroop effect: An integrative review. Psychological Bulletin. 109(2) 163 – 202. Stroop, J. R. (1935). Studies of verbal interference in serial verbal reactions. Journal of experimental psychology. 18(6) 643 – 662. page 26 of 28 Dean & Klein!Font Effect Appendix A: The card sorting task The purpose of this task was to ascertain which typefaces participants could correctly identify, to discover commonalities between correct and incorrect identifications and to assist us in the selection of the five typefaces used in this experiment. Sixteen typefaces (Arial, Bodoni, Comic Sans, Cooper Black, Copperplate Gothic, Courier, Fette Fraktur, Futura, Garamond, Helvetica, Keunstler Script, Ondine, Optima, Papyrus, Univers and Zaph Chancery) were selected based upon their ease of identification, frequency of exposure and visual distinction from one another. Participants were given two stacks of 16 cards each. On each card in the first stack was printed each of the 16 typeface names set in Franklin gothic (the same font Stroop used in his original materials—see figure 2). On each card in the second stack the pseudoword “Hamburgerfons” was printed set in each of the 16 previously mentioned typefaces. ! Twenty six participants were selected from students, staff, faculty and friends from both NSCAD University and Dalhousie University. This group included all 11 of the participants who were subsequently tested in the main experiment. The task was to match each typeface name with the pseudoword set in the corresponding typeface. The results of this task are presented in the form of a confusion matrix (Figure 8). page 27 of 28 Dean & Klein!Font Effect Figure 8: A confusion matrix of the stimuli and responses from the card sorting task (Appendix A). The right hand column illustrates specimens of the typefaces used in this portion of the study. The average performance on the five selected typefaces was about the same as the average for the 16 typefaces (58% correct). Considering only the 5 selected typefaces and responses with these five typeface names, the 26 participants made 75 correct responses and only five miscategorizations (for 94% correct). The average score for the entire population of 26 subjects used in the card sorting task was 58.4% and the average score for the population of 11 participants used in The Font Effect experiment was 77.4%. page 28 of 28