crt monitors: do they interfere with learning?

CRT monitors: Do they interfere with learning?

KATE J. GARLAND{ and JAN M. NOYES{

{School of Psychology, University of Leicester, University Road, Leicester LE1 7RH, UK;e-mail: [email protected]

{Department of Experimental Psychology, University of Bristol, 8 Woodland Road, Bristol BS8 1TN, UK

Abstract. Research suggests screen reading is slower andpossibly less accurate than reading from paper. Six studyand test sessions over 10 months examined correct scoresand retrieval responses for learning material presented viathese two media. Correct scores did not differ suggestingthat close matching of material can eliminate any decrementin reading speed or accuracy from screens. However, theway in which knowledge was retrieved varied between thepresentational formats. These differences were time relatedand suggest that repeated exposure and rehearsal ofcomputer-based information is necessary to equate knowl-edge application with that achievable from hard copyalternatives. It is suggested that this difference might bedue to cognitive interference caused by cathode-ray tube(CRT) monitor characteristics of refresh rates, fluctuatingluminance, and contrast levels.

1. Introduction

The continuing trend towards computer-basedlearning makes it important to establish the natureof any differences in learning outcomes between thisform of instruction and that achievable from moretraditional book/hard copy material. As Martin andPlatt (2001) pointed out, the increasing use ofelectronic material for learning purposes has implica-tions for print versus on-screen consumption. Thispaper reviews findings reporting differences in specificperformance measures (e.g. reading speed, accuracy,comprehension), research reporting comparative learn-ing outcomes between the two media, and examines along-term memory paradigm that introduces anotherform of ‘learning measure’. We present a longitudinalstudy that compared closely matched learning materialeither on a CRT monitor or in book format toexamine whether, and in what way, differences inlearning outcomes exist when current technologies areused.

2. Performance comparisons between CRT displays and

printed text

Research in the 1980s and early 1990s into readingperformance from CRT monitors focused on measuresof speed and accuracy (usually in the form of proof-reading tasks) and to a lesser extent, comprehension.While the last is more directly relevant to learning,speed and accuracy of reading are likely to reflect thedegree to which the reader has time for rehearsal oflearning material. Findings indicated that reading fromcomputers was slower than reading from printedmaterial (e.g., Muter et al. 1982, Gould and Grisch-kowsky 1984, Gould et al. 1986). However, somestudies reported no significant differences in readingspeed between the two presentational formats (e.g.Askwall 1985, Cushman 1986, Oborne and Holton1988, Muter and Maurutto 1991). There is evidence tosuggest that reading from computer screens is lessaccurate (e.g. Muter et al. 1982, Creed et al. 1987,Gould et al. 1987a). However, Gould et al. (1987b)reported no reliable differences in accuracy. Studiesthat measured comparative levels of comprehension,based on number of correct answers, suggested littledifference existed between the two media (e.g. Muter etal. 1982, Cushman 1986, Oborne and Holton 1988,Muter and Maurutto 1991), although Belmore (1985)found a marked reduction in comprehension in certaincircumstances. A closer inspection of these findingssuggests that inconsistencies might be partly due todifferences in quality between the screen and hard copymaterials available during that period, that is, aninsufficient degree of matching for quality in terms ofresolution and overall clarity. This is partly supportedby a more recent study (Picking 1997) that indicated nodifferences in proof reading of musical scores for hardcopy, static and animated computer presentations.

BEHAVIOUR & INFORMATION TECHNOLOGY, JANUARY–FEBRUARY 2004, VOL. 23, NO. 1, 43–52

Behaviour & Information TechnologyISSN 0144-929X print/ISSN 1362-3001 online # 2004 Taylor & Francis Ltd

http://www.tandf.co.uk/journalsDOI: 10.1080/01449290310001638504

The literature that reports comparative studiesbetween computer presented learning material and othermore traditional forms of teaching largely focuses onfindings that indicate how one method of instructionmay be better, in terms of final performance, thananother. The tasks under examination varied, as did themethodologies used and the similarity of the material ineach presentation format, and this may explain the lackof consistency in findings. For example, the use ofcomputer learning packages has been found to improvemarks significantly (e.g. MacDonald and Shields 1998)where this instruction has been used in addition totraditional teaching. Where the presentational formatswere more closely matched for amount and content ofmaterial, learning has been shown not to differ (e.g.Cockerton and Shimell 1997), or to be significantlybetter for printed learning material (e.g. Wilkinson et al.1997). More recently, Mayes et al. (2001) found thatalthough reading was slower from the screen, compre-hension (measured in terms of number of declarativequestions correctly answered) did not differ between thetwo media.

3. CRT monitor characteristics

There are certain characteristics of CRT screens thatmay affect reading and learning. Flicker, the visiblemovement of the screen image, can be evident if therefresh rate is below a certain threshold and/or thepersistence level of the phosphor coating is low.Montegut et al. (1997) found refresh rates of 60 Hz(some 16 ms between each fully refreshed screen image)reduced reading speed by some 3%, compared to refreshrates of 500 Hz (some 2 ms delay). The level ofluminance for CRT monitors is higher and less constantthan paper material (Blanco and Leirøs 2000), andcontrast (expressed in ratio terms foreground to back-ground) varies, with screens measuring between 2 : 1 to30 : 1, and paper between 1 : 5 and 1 : 10 (Grandjean1980).These factors have been demonstrated to affect brain

activity differentially. For example, Lyskov et al. (1998)found significantly different evoked potentials forvariations in both luminance, and refresh rates. Kam-mer et al. (1999) found differences associated withvariations in luminance that affected visual and higherorder cognitive processing. Variations in brain activityhave also been found for changes in contrast (Goodyearand Menon 1998), while Wollman and Palmer (1995)demonstrated interactions between the three monitorfeatures. In addition, performance for visual tasks(Kennedy and Baccino 1995), saccadic eye movements(Kennedy et al. 1998, Irwin et al. 2000), refresh rates

(Kennedy and Murray 1996), and visual acuity byluminance contrast (Wang and Chen 2000) have beenfound to be affected by one or other of these features.

4. Learning

4.1. Remember-Know paradigm

Learning impinges on the organization and applica-tion of long-term memory. According to Tulving (1983),knowledge initially enters the episodic memory system.As time passes, this knowledge becomes less distinct,abstract concepts are formed, and the reconstructedmemory transfers or shifts into the semantic memorysystem. Retrieval of episodic memory is characterized byrecollection in association with temporal and situationalcontextual details, while semantic retrieval lacks theseadditional details. Consequently, Tulving (1985) arguedthat memory contributions could be measured by askingparticipants whether they remembered an event (aRemember response), or knew in some other way thatthe event had occurred (a Know response). The changein representation from Remember to Know is consistentwith the schema theory of memory (Schank andAbelson 1977) where memories are representationsrather than exact records of experiences.

The temporal change of experience from the eventspecific to a more abstract construct and the distinctionbetween memories characterized by Remember andKnow subjective responses is supported empirically. Achange in knowledge representation over time wasfound by Tulving (1985). The proportion of Rememberresponses reduced (in favour of Know responses) whenparticipants were given recognition memory tests 7 daysafter the initial study. Similarly, Knowlton and Squire(1995) found a shift for recognition memory fromRemember to Know responses after seven days. Nuthall(2000) examined children’s learning over a year andfound, through detailed interviews, an increasingabstraction of the material learned and a progressiveloss of detail. It was suggested this indicated thatreconstructed memories, based on schema content, werereplacing more direct forms of recollection.

There is evidence to support the reliability of theassociation between retrieval states and type of knowl-edge. For example, Gardiner et al. (1998) foundRemember responses were associated with details ofrecollective experiences, especially those relating to theself, while Know responses lacked recollective details,and were associated with feelings of just knowing orfamiliarity. In addition, Hyman et al. (1998) foundparticipants recalled more information (e.g. visualdetails, temporal and situational aspects) with Remem-

44 K. J. Garland and J. M. Noyes

bered, compared to Known events. An examination ofparticipants who had used the extended Remember-Know paradigm within this research and a replicationstudy (Garland and Noyes, 2003) where participantsindicated retrieval states appeared to be a validreflection of the type of knowledge accessed and inturn, memory organization.Neuropsychological findings (e.g. Duzel et al. 1997,

Henson et al. 1999) and evidence of dissociations fromexperimental research for independent and participantvariables (for a review see, Gardiner and Richardson-Klavehn 2000), additionally suggest that Remember andKnow responses may represent distinctions betweenprocesses and behaviour, as well as different recollectiveexperiences.Further, patterns of brain activity for episodic and

semantic memory retrieval have been found to differ (fora review see, Cabeza and Nyberg 2000). Whilst someareas of the brain are activated for memory associatedwith both retrieval states apparently reflecting sharedcognitive processes, disassociations have been found byDuzel et al. (1997), and Knowlton and Squire (1995).

4.2. Learning and the remember-know paradigm

Conway et al. (1997) examined the nature of retrievalassociated with multiple-choice answers relevant to thefirst year of a psychology degree course. They used fourmemory awareness response categories, namely Re-member, Know (the answer is ‘just known’), Familiar(the answer selected is more familiar than othersprovided) and Guess. They found higher performingstudents gave more Remember than Know responses forquestions based on lecture courses, and more Knowthan Remember responses for questions relating toresearch methods courses, than lower graded students.After some 6 months a retest of the lecture courseshowed a shift to more Knows than Remembers. Thefindings suggest that in the long term, knowledge needsto be organised on a more abstract basis, rather thanbeing associated with additional contextual items for‘better’, or more readily applied learning.Herbert and Burt (2001) carried out a partial

replication of the Conway et al. (1997) study, and ingeneral, their findings were consistent. Similar trends forRemember and Know responses were found for the twotypes of courses. However, the shift from Remember toKnow was evident in a lecture course retest (after 24weeks) only for higher performing students. Themethods course initially showed more Know thanRemember responses; nevertheless, a shift was stillevident to a higher proportion of Knows in a retestafter nine weeks. These findings also suggest that higher

levels of knowledge indexed by Know responses willultimately reflect higher academic achievement. Inaddition, research recently conducted by the authors(Garland, Noyes, Perfect and Dennis, submitted)investigating retrieval times for Remember and Knowresponses indicated that knowledge associated withKnow responses was significantly faster than thatassociated with Remember responses. This appears toreflect a refined level of consolidation.

Collectively, these results indicate that an increase inthe structuring and consolidation of the knowledge isneeded, rather than merely the passage of time andsubsequent loss of contextual details, to reflect schema-tization as characterized by a shift in memory awarenessresponse. Thus, while the nature of the knowledge beinglearned may influence the manner of retrieval in theshort-term, in the longer-term, higher performingstudents appear to benefit from additional knowledgeconsolidation, as indexed by higher levels of Knowresponses.

4.3. Long-term learning, changes in retrieval andcomputer presentation

The present authors, in a pilot study, compared levelsof learning for an introductory history course. Onegroup received the learning material in booklet form,and the other read similar material from a computerscreen. The printed text group performed better than thecomputer-based group as measured by total number ofcorrect answers. In addition, the manner in which theknowledge was retrieved (measured by memory aware-ness ratings) was different, although not significantly so.Material for each group was identical in content, but notmatched in terms of layout. These findings suggestedthat differences between performance levels might existfor learning material presented via a computer screenand printed text, but that closer matching of thepresentation formats would be needed to examine morespecifically any effects. In a single study using the samematerial as reported here (Noyes and Garland 2003) nodifference was found in correct scores between the twopresentation formats, but significantly higher levels ofKnow compared to Remember responses were found forthose reading from printed text. Reading speed andaccuracy appear to be impaired when using CRTmonitors compared to printed material. It could beexpected that presentation of material on CRT monitorsmight influence learning outcomes, in particular thoseinvolved in memory organisation and retrieval, eitherdue to these factors, or to interference and its effect oncognitive processes. However, Noyes and Garland alsofound that neither reading speed (for a single page of

45CRT monitors

text), nor study speed (the learning material read at‘normal’ speed for the intention of learning) differedbetween the two conditions. It would appear that closelymatched material eliminates differences in both readingspeed and comprehension, and this study examines thereliability of the second finding.In addition, an examination of changes in memory

awareness over time was carried out both in the short-and longer-term, with seven test sessions over 10months. The same questions were used in the initialsessions in order to examine improvements in scores.The introduction of matched questions for the laterstudies was used to ensure any improvements reflectedthe repeated presentation of the subject material, ratherthan memory for specific questions and answers, so thata ‘better’ estimate of ‘learning’ could be derived. Anumber of variables have been found to influenceperformance with computers, namely participants’ age(e.g. Freudenthal 2001), sex (e.g. Harris 1999), andcomputer experience and its link with user confidence(e.g. Brosnan and Lee 1998). In order to reduce possibleeffects due to these factors, the sample included a highproportion of full-time users of computers, includingprogrammers and developers, and groups were matchedfor computer experience, sex and age.It was predicted that learning from the computer

presented material would be similar to that from printedmaterial. It was also expected that those in theComputer group would give more Remember responsesthan those in the Print group. A shift from Remember toKnow responses over time was expected in bothconditions. Earlier findings (Tulving 1983, Conway etal. 1997, Herbert and Burt 2001) suggested this shiftcould occur at any point between seven days and sixmonths depending on the nature of the learningmaterial. However, it was expected that findings wouldreflect an ongoing process of schematization, rather thana single point of change.

5. Methodology

Details common to all test sessions are describedinitially, followed by information specific to theindividual studies.

5.1. Design

A within-subjects design was employed for thecontent of the material and the responses required. Abetween-subjects design was employed for the form ofpresentation of the learning material: computer- orprint-based (hereinafter referred to as Computer and

Print, respectively). The dependent variables werenumber of correct answers, and the nature of memoryretrieval indexed by memory awareness ratings.

5.2. Participants

Initial allocation of participants to the two conditionswas matched as far as practicable in terms of age(Computer M=28.72, Print M=29.60 years), sex(Computer=11 men, 14 women, Print=11 men and14 women), and computer experience (years and extentof use), but was otherwise random. Participantsremained in their originally allocated condition for allsessions. A high proportion of participants worked withcomputers on a full time basis and included program-mers, technicians and a number were involved indeveloping computer-based materials. None had re-ceived any formal teaching in economics, or were knownor observed to have any visual or other impairment thatmay have affected their ability to complete the task.

5.3. Apparatus and materials

The Computer group received their learning materialvia a 15 inch, SVGA monitor powered by a Memax‘686 Family Model’ personal computer. Material waspresented via a Web browser that accessed an Intranetsite. The Print group was provided with a bookletcontaining the same learning material.

The study material comprised an introductory eco-nomics course, adapted from WinEcon# (TLTP Eco-nomics Consortium 1998), a university course developedby the UK Higher Education Funding Bodies. Mod-ifications included removing internal hyperlinks betweenpages and presenting the material within 22 pages,rather than 67 pages, but without altering the textualcontent. These final pages were used for both presenta-tion groups and were matched as closely as possible forsize, colour and resolution. The booklet effectivelycomprised individual screen shots on each page.Navigation within the Computer material was limitedto ‘forward’ and ‘backward’ button hyperlinks betweenadjoining pages, and standard keyboard commands.Questions comprised a selection from the course,together with additional ones compiled by an economicsteacher.

5.4. Procedure

Participants read the instructions, which were aug-mented verbally to ensure the task requirements were


fully understood. Each participant was given a studyperiod to read (with the intention of learning) thematerial provided. They were instructed to use all thetime available, re-reading any sections they wished oncethey had completed the initial reading. Participants weretold that they would receive 20 questions, with multiple-choice answers, on any aspect of the material after thestudy period, and that they would also be required toindicate the manner in which they retrieved their answer.The latter would comprise four options: Remember,Know, Familiar and Guess (for definitions see Appen-dix). Participants were instructed to select the memoryawareness rating that best reflected their initial recall ofthe answer. Immediately after the study periods, theparticipants were presented with printed questionpapers. There was no time limit for answering.

5.4.1. Sessions 1 to 4: The same 50 participantscompleted Sessions 1 to 4. Of these, four undergraduatestook part as a course requirement, and the remainder,staff and students, were volunteers (15 unpaid, 31 paid).The 22 men and 28 women had an age range of 18 to 53years (M=29.16, SD=9.42). All participants com-pleted four study sessions of 20 min duration, on thesame material, on ‘Day 1’, ‘Day 3’, ‘Day 13’ and ‘Day20’. At the end of each study session participantsanswered the same set of 20 questions.

5.4.2. Session 5: The original 50 participants com-pleted an additional set of 20 questions on Day 20,immediately after the first set of questions, and withoutfurther study time. These were matched to the originalselection (Session 1 to 4) for number of possibleresponses, and also the factual or conceptual contentacross the two sets.

5.4.3. Session 6: A total of 28 paid volunteers (15men and 13 women) who had completed the earlier tests,participated in this study, approximately 3 months afterSession 1. Their age ranged from 19 to 53 years(M=32.32, SD=9.70). The procedure employed inSessions 1 to 5 was also used for this session. However,study time was reduced from 20 to 15 min because thiswas deemed sufficient for a revision session, based uponparticipant feedback from the earlier studies. Twentyquestions were used, which comprised a mixture of thosecontained within the original two sets.

5.4.4. Session 7: Participants comprised 21 paidvolunteers (6 men and 15 women) from Sessions 1 to5, some 10 months after Session 1. The age range was 19to 53 years (M=31.43, SD=9.48). The design,procedure and materials were the same as that forSession 6.

6. Results

6.1. Correct answers

In all sessions the means for correct responses showedlittle difference between the Computer and Print groups(see table 1). A mixed, analysis of variance (ANOVA)was carried out for Sessions 1 to 4, for condition (twolevels)6 session (four levels). Differences between con-ditions, and the interaction of condition x session werenot significant. However, there was a significant maineffect for session, F(3, 144)=36.78, p5 0.001. Theeffect size, as demonstrated by Eta Squared (Z2), was0.43. Pairwise comparisons (using the Bonferroniadjustment) showed that mean scores for Session 1 weresignificantly lower than those for Sessions 2, 3 and 4(p5 0.001), while no other session comparisons differed.

The mean improvements in correct responses (Session4 scores less Sessions 1 scores), were 3.08 (SD 2.31) forthe Computer group and 2.52 (SD 3.06) for the Printgroup. A one-way ANOVA indicated the difference wasnot significant (F5 1). The improvement in learningwas assessed between the two sets of matched questionsand was, therefore measured as Session 5 scores lessSession 1 scores. The mean differences were 1.88 (SD2.74) for the Computer group and 2.20 (SD 2.87) for thePrint group. A one-way ANOVA indicated the differ-ence was not significant (F5 1).

6.2. Memory awareness frequencies

Total frequencies for memory awareness ratings wereexamined. However, in view of variations in participant

Table 1. Mean correct responses for sessions 1 to 7(SD in parentheses)

Mode of presentation

Session Computer Print Overall N

1 11.28(3.18)

11.80(2.72)

11.54(2.94)

50

2 13.44(2.65)

14.00(2.40)

13.72(2.52)

50

3 14.40(2.60)

14.44(2.35)

14.42(2.45)

50

4 14.36(3.25)

14.36(2.45)

14.36(2.85)

50

5 13.16(2.15)

13.80(2.22)

13.48(2.19)

50

6 12.64(2.92)

11.50(3.06)

12.07(2.19)

28

7 11.10(3.14)

10.73(3.32)

10.90(3.16)

21

47CRT monitors

numbers, mean frequencies are reported in table 2.These suggest that Know responses increased morerapidly, largely at the expense of Remember responses,and a shift from Remember to Know responses occurredearlier in the Print condition than the Computercondition. Familiar and Guess response trends showedlittle difference between or within conditions. A Chi-squared, single sample test on total frequencies (Sessions1 to 7) for Remember, Know, Familiar and Guessresponses (1243, 779, 480 and 225, respectively), showeda significant effect of awareness, w2(3)=841.63,p5 0.001. Individual planned comparisons showed eachawareness category differed significantly from all othercategories (p5 0.001).Comparisons of frequencies for Remember and Know

responses between Computer and Print conditionsrevealed significant differences in Session 3 (w2=6.67,p=0.01, Cramer’s V=0.108), Session 4 (w2=18.30,p5 0.01, Cramer’s V=0.176), and Session 5 (w2=4.10,p5 0.05, Cramer’s V=0.095). Further, the differencebetween Computer and Print frequencies for Rememberand Know responses in Session 6 approached signifi-cance (w2=3.75, p=0.053, Cramer’s V=0.139).Remember and Know response frequencies, within

conditions, were compared for each of the individualstudies using Chi-squared analyses (see table 3). In theComputer condition, Remember responses were signifi-cantly more frequent than Know responses for Sessions1 to 5, and showed no difference in Sessions 6 and 7. Inthe Print condition there were significantly moreRemember than Know responses only in Sessions 2and 3. There were no differences in frequencies forSessions 1, 4, 5 and 6, while in Session 7 there weresignificantly more Know responses than Rememberresponses.

7. Discussion

7.1. Comprehension and effects over time

Correct scores did not differ significantly between thetwo presentation formats in any of the test sessions.Further, measures for improvement in scores andlearning did not differ between groups. These findingsare inconsistent with the lower scores found forcomputer presentation in the authors’ pilot study, andwith earlier reports of poorer accuracy and substantiallyslower reading from screens than from printed copy.Findings such as those by Gould and Grischowsky(1984) appear less relevant for today’s modern CRTmonitor images and printing technologies. As Gould etal. (1987a) and Gould et al. (1987b) reported, andconsistent with the Noyes and Garland (2003) findings,quality of the presentational formats appears to have amajor influence on both reading speed for learning andcomprehension (as measured by correct scores). Indeed,there was no evidence during testing to show thatreading was appreciably slower in the Computercondition; all participants completed the material withinthe time allocated.

Previous studies comparing learning between differentforms of instruction were inconclusive. This appearslargely due to a lack of direct comparability between thepresentation or instruction formats. Where learningmaterial is closely matched the present findings suggestthere is little difference in the number of correct scoresbetween the two media. Any decrement in reading speedand/or comprehension that might be attributable toCRT monitor presentation of learning material, appearsinsufficient to affect learning performance adverselyproviding the two media forms are closely matched

Table 2. Mean memory awareness frequencies for sessions 1 to 7 (SD in parentheses)

Memory awareness category

Session Condition Remember Know Familiar Guess

Session 1 Computer 4.00 (2.52) 2.56 (2.57) 2.84 (2.03) 2.16 (1.95)(n=50) Print 3.96 (2.94) 3.12 (2.65) 3.04 (1.93) 1.88 (1.33)Session 2 Computer 6.96 (2.94) 3.24 (2.47) 1.80 (1.78) 1.36 (2.14)(n=50) Print 6.68 (3.97) 3.92 (2.94) 2.48 (2.18) 0.76 (1.13)Session 3 Computer 7.84 (4.13) 3.80 (3.27) 2.08 (2.08) 0.84 (1.49)(n=50) Print 6.44 (3.98) 4.72 (3.85) 2.88 (2.64) 0.60 (1.08)Session 4 Computer 7.88 (3.91) 3.80 (3.25) 2.24 (2.59) 0.64 (1.29)(n=50) Print 5.96 (3.41) 6.00 (3.84) 1.84 (2.29) 0.76 (1.30)Session 5 Computer 5.12 (3.41) 3.48 (3.14) 3.08 (3.01) 1.48 (2.08)(n=50) Print 4.80 (3.54) 4.92 (3.26) 3.16 (3.01) 0.88 (1.20)Session 6 Computer 4.07 (2.73) 3.57 (2.74) 3.64 (2.10) 1.79 (2.69)(n=28) Print 2.77 (2.77) 3.38 (2.60) 3.69 (3.04) 1.38 (1.76)Session 7 Computer 2.60 (3.06) 3.90 (2.85) 2.70 (1.57) 1.90 (1.91)(n=21) Print 2.09 (2.34) 3.64 (2.34) 2.82 (2.32) 2.18 (1.33)


visually. This is not inconsistent with the suggestion byMontegut et al. (1997), that a reduction in reading speedof approximately 5% could be expected due to standardmonitor refresh rates. Any additional rehearsal time andsubsequent benefit in scores this might have given to thePrint users was likely to be too small to be evident in thefindings.Two factors that might have influenced the number of

correct scores were, first, the academic ability of theparticipants and, secondly, existing knowledge of thesubject matter. The possible influence of these factorsshould have been reduced due to allocation to condi-tions being random (after matching for age, sex andcomputer experience), and the lack of any prior, formalinstruction in economics for all participants. However,the latter restriction was not sufficient to control for lessformal, general knowledge of the subject matter.Indications of achievement were, perhaps, more readilyexpressed by improvement in scores (Session 4 lessSession 1) and level of learning (Session 5 less Session 1).These figures should have been influenced less by anyvariation in participants’ prior knowledge of the topic,and the lack of a difference between groups suggests thatany influence due to variations in prior knowledge wasminimal.Main effects of test session were found for all

analyses. Session 1 scores were significantly lower thanthose for Sessions 2, 3 and 4, but these later scores didnot differ. This suggests that the additional rehearsalprovided in the third and fourth study periods wasinsufficient in its instructive content to enable learningover and above that gained from two readings of thematerial. It is suggested that findings for Sessions 5 to 7might reflect the changes in questions, the reduced

number of participants and possibly boredom or poormotivation due to repetition of the same material, ratherthan learning patterns.

7.2. Remember-Know responses and effects over time

A significant effect of memory awareness was foundacross all sessions, with each response type reliablydiffering from the others. It should be noted that thisinitial difference has subsequently been replicated by theauthors (Noyes and Garland 2003). In the Computercondition, Remember frequencies were significantlygreater than Knows for Sessions 1 to 5, with nodifferences found in Sessions 6 and 7. This suggests thata shift in the balance of the form of memory retrieval didnot occur until after five periods of study, over 3months. By contrast, when presentation was in printedform, Remember responses were more frequent thanKnows only in Sessions 2 and 3. By Session 7 Knowresponses were significantly higher than Rememberresponses. This suggests that the shift of knowledgefrom episodic to semantic memory occurred earlier forprinted, learning material, namely after four studyperiods spanning 20 days. Indeed, the lack of differencebetween Remember and Know frequencies in Session 1suggests that greater use of the semantic memory may bemade much earlier when material is presented via hardcopy.

The shift from Remember to Know responses foundby Tulving (1985) and Knowlton and Squire (1995)demonstrated a significant reduction in proportion ofRemember responses over seven days. A predominanceof Knows was not observed. However, in a second

Table 3. Within condition differences, by session, for remember and know frequencies

Frequency

Session Condition Remember Know w2 Significance

1 (Day 1) Computer 100 60 10.00 p5 0.01Print 99 82 1.6 NS

2 (Day 3) Computer 160 73 32.49 p5 0.01Print 181 106 19.60 p5 0.01

3 (Day 13) Computer 184 86 35.57 p5 0.01Print 173 127 7.05 p5 0.01



6 (3 Months) Computer 57 44 1.67 NSPrint 40 54 2.09 NS

7 (10 months) Computer 26 39 2.60 NSPrint 23 40 4.59 p5 0.01

NS=not significant.

49CRT monitors

experiment, Knowlton and Squire found similiar Re-member and Know levels after seven days. In bothstudies recognition tasks for single items were employed.Tulving presented stimuli verbally, while Knowlton andSquire used printed material and a between-subjectsdesign. These design differences may explain the lack ofconsistency between their findings and those reportedhere.More directly comparable are the findings by Conway

et al. (1997) and Herbert and Burt (2001). In these twostudies participants were tested on cohesive material ofsome relevance to the participants, rather than singleitem word lists, and where both Familiar and Guessretrieval categories were provided. In the former, Knowresponses were found to be reliably more dominant thanRemember responses in a second test after 6 months.This trend is consistent with our findings, but the lack ofadditional, intermediate testing does not permit a morespecific indication of the timing and general progress ofschematisation. Herbert and Burt by contrast, found areduction in Remembers for the lecture course tests aftersome 6 months, but they remained dominant, and thisdifference was only observed for higher performingstudents. They argued this showed that loss ofcontextual details over time is insufficient for a changein retrieval responses, rather that some form ofrestructuring of the material is also required. Theysuggested that this consolidation might be dependent onstudent ability. However, this is inconsistent with ourfindings. The sample comprised not only a mixture ofstudents with varying (although not assessed ability),but also staff with mixed academic backgrounds. It issuggested, therefore, that schematization reflected by ashift from Remember to Know retrieval responses, ismore likely to be a process characterised by the degreeof restructuring of the material, rather than academicability. This appears to be partially supported byHerbert and Burt’s findings for the research methodsretest. Participants gave more Know responses initially,which might be explained by the use of third yearstudents who would have often encountered the learningmaterial. However, it was predominantly lower per-forming students who exhibited the additional shiftvisible after nine weeks. This suggests that whileacademic ability might be reflected in the speed withwhich schematization occurs, this consolidation can beachieved notwithstanding academic ability.Reported findings focused on Remember and Know

responses. While Conway et al. (1997) saw the Familiarcategory as discrimination within the Know state, ourfindings suggest Familiar responses have greater simi-larity with Guesses than with Knows, with a low level ofaccuracy appearing more representative of limitedmemory access. Familiar responses are only applicable

in a multiple-choice situation where a number ofpossible answers are given. It is suggested that withoutthe cues that these alternatives provide, participantswould have to guess. Rather than Familiar being an‘extension’ of Know, it is an extension of Guess, butwith some feeling of familiarity when alternativeanswers are provided.

8. Conclusions

The findings suggest that presentation of material ona CRT monitor influences, according to Tulving’s (1983,1985) theory, memory organization within the episodicand semantic memory systems in a manner differentfrom material in printed form. The greater use ofepisodic memory could possibly be explained bycomputer ‘images’ being more novel and/or memorableand thus, the transfer of information to the semanticmemory (the formation of schemas) was slower.However, the inclusion of full-time computer users andthe generally high level of computer experience, as far aspracticable, across groups should have reduced thelikelihood of novelty of presentation being a factor.Indeed, the nature of the booklet presentation wasarguably of greater novelty to all participants than anydegree of novelty when the same material was presentedon screen. In addition, findings showed there were nodifferences for level of computer experience; similarly,the participant characteristics of age, sex and perceptualstyle (as measured by the Embedded Figures Test) werefound not to influence the results.

An alternative explanation is that features of the CRTmonitors interfered with the cognitive processes in-volved in learning, ultimately being reflected in themanner of memory retrieval. This is supported byneuropsychological evidence indicating that interferencemight occur during visual processing (Goodyear andMenon 1998), and indeed, beyond the visual cortex(Lyskov et al. 1998, Kammer et al. 1999). Interferenceappears due to a combination of the effects of luminanceand contrast on saccadic eye movements and visualacuity (Kennedy et al. 1998, Irwin et al. 2000, Wang andChen 2000); and the effects of the image degradationinherent in refreshed displays (Kennedy and Murray1996, Montegut et al. 1997). A direct comparison ofbrain areas associated with Remember and Knowresponses and those associated with CRT monitorcharacteristics was not possible from the currentliterature, but this does suggest an avenue of futureinvestigation.

Two important conclusions arise from our findings.The presentation of learning material on CRT monitorspermits comparable knowledge assimilation to that


achievable from hard copy. This reflects major advancesin the technology of computer monitors since the earlyresearch work that focused on comparative readingspeeds and comprehension. Hence, it is suggested thereis no longer a decrement in these performance measuresproviding material is visually matched. It was found thatknowledge was transferred from the episodic memory(indexed by Remember responses) to the semanticmemory (indexed by Know responses). However, thetiming of this shift appears dependent on the nature ofthe presentation. The knowledge transition was muchmore rapid for those learning from printed material,suggesting less interference to the process of schematiza-tion, and consequently more readily applied knowledge.Hence, this suggests there still appears to be a benefitattached to learning from paper-based rather thancomputer-based materials.

References

ASKWALL, S., 1985, Computer supported reading vs readingtext on paper – a comparison of two reading situations.International Journal of Man-Machine Studies, 22, 425 – 439.

BELMORE, S. M., 1985, Reading computer-presented text.Bulletin of the Psychonomic Society, 23, 12 – 14.

BLANCO, M. J. and LEIRØS, L. I., 2000, Temporal variation inthe luminance level of stimuli displayed on a cathode-raytube monitor: effects on performance on a visual vigilancetask. Ergonomics, 43, 239 – 251.

BROSNAN, M. and LEE, W., 1998, A cross-cultural comparisonof gender differences in computer attitudes and anxieties:The United Kingdom and Hong Kong. Computers inEducation, 14, 559 – 577.

CABEZA, R. and NYBERG, L., 2000, Imaging Cognition II: Anempirical review of 275 PET and fMRI studies. Journal ofCognitive Neuroscience, 12, 1 – 47.

COCKERTON, T. and SHIMELL, R., 1997, Evaluation of ahypermedia document as a learning tool. Journal ofComputer Assisted Learning, 13, 133 – 144.

CONWAY, M. A., GARDINER, J. M., PERFECT, T. J., ANDERSON, S.J. and COHEN, G., 1997, Changes in memory awarenessduring learning: The acquisition of knowledge by psychol-ogy undergraduates. Journal of Experimental Psychology:General, 126, 393 – 413.

CREED, A., DENNIS, I. and NEWSTEAD, S., 1987, Proof-readingon VDUs. Behaviour & Information Technology, 6, 3 – 13.

CUSHMAN, W. H., 1986, Reading from microfiche, VDT andthe printed page. Human Factors, 28, 63 – 73.

DUZEL, E., YONELINAS, A. P., MANGUN, G. R., HEINZE, H.-J.and TULVING, E., 1997, Event-related brain potentialcorrelates of two states of conscious awareness in memory.Proceedings of the National Academy of Sciences of theUnited States of America, 94, 5973 – 5978.

FREUDENTHAL, D., 2001, Age differences in the performance ofinformation retrieval task. Behaviour & Information Tech-nology, 20, 9 – 22.

GARDINER, J. M., RAMPONI, C. and RICHARDSON-KLAVEHN, A.,1998, Experiences of remembering, knowing, and guessing.Consciousness and Cognition, 7, 1 – 26.

GARDINER, J. M. and RICHARDSON-KLAVEHN, A., 2000, Re-membering and Knowing. In E. Tulving and F. I. M. Craik(eds) The Oxford handbook of memory (New York: OxfordUniversity Press), pp. 229 – 244.

GOODYEAR, B. G. and MENON, R. S., 1998, Effect of luminancecontrast on BOLD fMRI response in human primary visualareas. Journal of Neurophysiology, 79, 2204 – 2207.

GOULD, J. D., ALFARO, L., BARNES, V., FINN, R., GRISCHKOWSKY,N. and MINUTO, A., 1987a, Reading is slower from CRTdisplays than from paper: Attempts to isolate a singlevariable explanation. Human Factors, 29, 269 – 299.

GOULD, J. D., ALFARO, L., FINN, R., HAUPT, B. and MINUTO, A.,1987b, Reading from CRT displays can be as fast as readingfrom paper. Human Factors, 29, 497 – 517.

GOULD, J. D. and GRISCHKOWSKY, N., 1984, Doing the samework with hard copy and cathode-ray tube (CRT) computermonitors. Human Factors, 26, 323 – 337.

GRANDJEAN, E., 1980, Ergonomics of VDUs: Review of presentknowledge. In E. Grandjean and E. Vigliana (eds) Ergo-nomic aspects of visual display terminals (London: Taylor &Francis Ltd.), pp. 1 – 12.

HARRIS, D. 1999, Attitudes towards end-user computing: astructural equation model. Behaviour & Information Tech-nology, 18, 109 – 125.

HENSON, R. N. A., RUGG, M. D., SHALLICE, T., JOSEPHS, O. andDOLAN, R. J., 1999, Recollection and familiarity in recogni-tion memory: An event-related functional magnetic reso-nance imaging study. Journal of Neuroscience, 19, 3962 –3972.

HERBERT, D. M. B. and BURT, J. S., 2001, Memory awarenessand schematisation: Learning in the university context.Applied Cognitive Psychology, 15, 617 – 637.

HYMAN, I. E. JR., GILSTRAP, L. L., DECKER, K. and WILKINSON,C., 1998, Manipulating remember and know judgements ofautobiographical memories: An investigation of falsememory creation. Applied Cognitive Psychology, 12, 371 –386.

IRWIN, D. E., COLCOMBE, A. M., KRAMER, A. F. and HAHN, S.,2000, Attentional and oculomotor capture by onset,luminance and color singletons. Vision Research, 40,

1443 – 1458.KAMMER, T., LEHR, L. and KIRSCHFELD, K., 1999, Corticalvisual processing is temporally dispersed by luminance inhuman subjects. Neuroscience Letters, 263, 133 – 136.

KENNEDY, A. and BACCINO, T., 1995, The effects of screenrefresh rate on editing operations using a computer mousepointing device. Quarterly Journal of Experimental Psychol-ogy Section A – Human Experimental Psychology, 48, 55 – 71.

KENNEDY, A., BRYSBAERT, M. and MURRAY, W. S., 1998, Theeffects of intermittent illumination on a visual inspectiontask. Quarterly Journal of Experimental Psychology SectionA – Human Experimental Psychology, 51, 135 – 151.

KENNEDY, A. and MURRAY, W. S., 1996, Eye movement controlduring the inspection of words under conditions of pulsatingillumination. European Journal of Cognitive Psychology, 8,381 – 403.

KNOWLTON, B. J. and SQUIRE, L. R., 1995, Remembering andknowing – 2 different expressions of declarative memory.Journal of Experimental Psychology: Learning, Memory, andCognition, 21, 699 – 710.

LYSKOV, E., PONOMAREV, V., SANDSTROM, M., MILD, K. H. andMEDVEDEV, S., 1998, Steady-state visual evoked potentials tocomputer monitor flicker. International Journal of Psycho-physiology, 28, 285 – 290.

51CRT monitors

MACDONALD, Z. and SHIELDS, M. A., 1998, Winecon: Anevaluation. Journal of Economic Surveys, 12, 221 – 231.

MARTIN, L. A. and PLATT, M. W., 2001, Printing and screenreading in the medical school curriculum: Guttenberg vs. thecathode ray tube. Behaviour & Information Technology, 20,143 – 148.

MAYES, D. K., SIMS, V. K. and KOONCE, J. M., 2001,Comprehension and workload differences for VDT andpaper-based reading. International Journal of IndustrialErgonomics, 28, 367 – 378.

MONTEGUT, M. J., BRIDGEMAN, B. and SYKES, J., 1997, Highrefresh rate and oculomotor adaptation facilitate readingfrom video displays. Spatial Vision, 10, 305 – 322.

MUTER, P., LATREMOUILLE, S. A., TREURNIET, W. C. and BEAM,P., 1982, Extended reading of continuous text on televisionscreens. Human Factors, 24, 501 – 508.

MUTER, P. and MAURUTTO, P., 1991, Reading and skimmingfrom computer screens and books: The paperless officerevisited? Behaviour & Information Technology, 10, 257 –266.

NOYES, J. M. and GARLAND, K. J., 2003, VDT versus paper-based reading: Reply to Mayes, Sims, and Koonce.International Journal of Industrial Ergonomics, 31(6), 411 –423.

NUTHALL, G., 2000, The role of memory in the acquisition andretention of knowledge in science and social studies units.Cognition and Instruction, 18, 83 – 139.

OBORNE, D. J. and HOLTON, D., 1988, Reading from screenversus paper: There is no difference. International Journal ofMan-Machine Studies, 28, 1 – 9.

PICKING, R., 1997, Reading music from screen vs paper.Behaviour & Information Technology, 16, 72 – 78.

SCHANK, R. C. and ABELSON, R. P., 1977, Scripts, plans, goalsand understanding (Hillsdale, NJ: Lawrence Erlbaum As-sociates Inc.).

TLTP ECONOMICS CONSORTIUM, 1998, WinEcon (Version 5.0).Oxford: Blackwells.

TULVING, E., 1983, Elements of episodic memory (Oxford:Oxford University Press).

TULVING, E., 1985, Memory and consciousness. CanadianPsychology, 26, 1 – 12.

WANG, A. H. and CHEN, M. T., 2000, Effects of polarity andluminance contrast on visual performance and VDT displayquality. International Journal of Industrial Ergonomics, 25,415 – 421.

WILKINSON, S., CRERAR, A. and FALCHIKOV, N., 1997, Bookversus hypertext: exploring the association between usabilityand cognitive style [Online]. Available: http://dcs,napier.-ac.uk/hci/simon/Research_Details.html [1999].

WOLLMAN, D. E. and PALMER, L. A., 1995, Phase-locking ofneuronal responses to the vertical refresh of computerdisplay monitors in cat lateral geniculate-nucleus and striatecortex. Journal of Neuroscience Methods, 60, 107 – 113.

Appendix

Memory Awareness Definitions

Remember=when you recalled a specific episode(‘saw’ or ‘heard’ it in your mind) with the recalledmemory, e.g. see an image of the page or diagram etc.Know=the answer just stood out, you did not recalla specific episode, e.g. when asked your name, youjust know it.Familiar= this is when you neither recalled theanswer by associating it with a specific episode, norknew it, but the answer you chose did seem morefamiliar than any of the other options.Guess=guess.


crt monitors: do they interfere with learning?

Documents