FundingSurgeonUnderg

Accepte

ReprintLaboratStreet, L

0039-60

� 2014

http://d

Performing under pressure: Quiet eyetraining improves surgical knot-tyingperformanceJoe Causer, PhD,a Joan N. Vickers, PhD,b Ryan Snelgrove, MD,c Gina Arsenault,b andAdrian Harvey, MD, FRCS,c Liverpool, UK, and Calgary, Alberta, Canada

Background.We examined the effectiveness of traditional technical training (TT) and quiet eye training(QET) on the performance of 1-handed square knot tying among first-year surgery residents undernormal and high-anxiety conditions.Methods. Twenty surgery residents were assigned randomly to 1 of 2 groups and completed pretest,training, and simple and complex retention tests under conditions of high and low anxiety. The TTgroup received traditional instruction on improving hand movements; the QET group received feedbackon their gaze behaviors. Participants wore an eye tracker that recorded simultaneously their gaze andhand movements. Dependent variables were knot tying performance (%), quiet eye duration (%),number of fixations, and total movement time (s).Results. Both groups improved their knot tying performance (P < .05) from pretest to the low anxietyconditions (mean difference: QET, 28%; TT, 17%); however, only the QET group maintained theirknot tying performance under the high-anxiety conditions (mean difference: QET, 18%; P < .05), withthe TT group decreasing their performance close to pretest levels (P > .05). The QET group alsodemonstrated more efficient gaze and hand movements post training.Conclusion. These data demonstrate the effectiveness of training gaze behaviors, not only to improve theeffectiveness and efficiency of performance, but also to mediate negative effects of anxiety on performance.These findings may have important implications for medical educators and practitioners, as well assurgeons who may be (re)training or learning new procedures. (Surgery 2014;156:1089-96.)

From the Brain and Behaviour Laboratory,a Liverpool John Moores University, Liverpool, UK; and theFaculty of Kinesiologyb and the Faculty of Medicine,c University of Calgary, Calgary, Alberta, Canada

SURGERY is a highly complex, dynamic, and unpre-dictable environment, with critical decisions andactions being implemented under high levels ofanxiety. Despite this, relatively little is known abouthow simple surgical tasks, such as knot tying, canbe affected by increases in anxiety. In other do-mains with instances of high anxiety, such as lawenforcement and sport, anxiety has been shownto decrease cognitive performance and impactnegatively on the actions of individuals.1 Specif-ically, increases in anxiety can affect the efficiencyand effectiveness of attention allocation, which

was provided by the Royal College of Physicians ands, Canada, and the University of Calgary Program forraduate Research Experience.

d for publication May 12, 2014.

requests: Joe Causer, PhD, Brain and Behaviourory, Faculty of Science, Tom Reilly Building, Byromiverpool, L3 3AF UK. E-mail: j.causer@ljmu.ac.uk.

60/$ - see front matter

Elsevier Inc. All rights reserved.

x.doi.org/10.1016/j.surg.2014.05.004

leads to individuals not picking up critical informa-tion from the environment.2 Attention can bemeasured indirectly by analyzing gaze behaviors,such as where an individual looks (fixations) andfor how long.3 Furthermore, gaze behaviors canbe trained to overcome the potential negative ef-fects of anxiety.4 The aim of the current studywas to examine whether training gaze behaviorsin a knot tying task would be more effective thantraditional technical training (TT) methods forfirst-year surgery residents.

There are a variety of gaze metrics that can beused as a measure of attention; however, the quieteye period (QE) has been demonstrated to be areliable characteristic of both expertise and suc-cess. QE is the final fixation on a specific locationbefore the initiation of a critical movement.5,6

Longer QE periods have been associated withexpert performance in sport,7 law enforcement,8

the military,9 and medicine.10 The QE is thoughtto represent the time required to organize the neu-ral networks controlling the action.3 This assertionis supported by the observation that QE duration

SURGERY 1089

SurgeryNovember 2014

1090 Causer et al

increases with task difficulty, because more com-plex actions usually require increased informationprocessing.11 Although researchers have reportedthat QE can be affected negatively by anxiety,4

there is evidence that maintaining a longer QEin stressful situations can mediate the negative ef-fects of anxiety and enable the individual to main-tain performance levels.4 Results from thesetraining studies have shown that, as a consequenceof the longer QE, actions can also become moreorganized, leading to a more efficient movementpattern.

QE research in medicine has demonstrated lessexperienced surgeons tend to move their visionbetween the target location and their hand ortool.10 Furthermore, expert surgeons tend to fixatethe target location for longer than novice or lessexperienced surgeons.12,13 This longer QE en-hances cognitive ‘‘slowing down,’’ which Moultonet al found to be characteristic of expert sur-geons.7,14 The expert surgeon cognitively refocusesand brings an increased level of attention to bearduring critical times during an operation.

Despite previous studies analyzing gaze andmovement behavior in surgical skills,10,15-17 thereis a paucity of literature on how these skills are per-formed under high-anxiety situations.18 Further-more, studies to investigate the effectiveness ofQE training (QET) programs to decrease poten-tially negative effects of anxiety on surgical skillperformance are lacking.19 The 2 training studiesto date using QE in surgical skills training haveused novice participants20 or surgery trainees21 inlow-anxiety conditions. Given that surgeonsroutinely perform complex procedures in highlystressful, unpredictable environments, understand-ing how anxiety can affect surgical performanceand how we can decrease any negative effects ofanxiety is critical.22

The aim of the study was to examine whether aprogram of either QET or traditional TT wouldincrease knot tying performance in 1-handedsquare knots among first-year surgery residentsunder high- and low-anxiety scenarios. Simpleand complex conditions were also included todetermine whether there were differences betweengroups in conditions with demands for high infor-mation processing. Gaze and movement data wererecorded during all conditions. We predicted thatboth training groups would increase their knottying performance after the training, but we hy-pothesized that the QET group would demonstratemore efficient gaze behaviors post-training, asevidenced by longer QE and fewer fixations. Theseimprovements were expected to be maintained for

the QET group in the high-anxiety condition, witha decrement in these metrics predicted for the TTgroup.

METHODS

Participants. We recruited 20 first-year surgeryresidents (mean age, 26; range, 25–29). All partici-pants had received basic knot tying training previ-ously as part of their surgical skills module.Participantswere randomlyassignedequally toeithera QETor TT group. All had normal or corrected tonormal vision. Participants volunteered for the study,and ethics approval was obtained through the localConjoint Health Ethics Research Board.

Equipment. A SensoMotoric Instruments (SMI)ETG eye-tracking system (Boston, MA) was used tocollect gaze and hand movement data. The SMI-ETG is a lightweight (76 g), glasses-mounted,binocular system that uses dark pupil tracking tomeasure point of gaze with a spatial resolution of0.18 and temporal resolution of 30 Hz (33.3 ms perframe), with a built-in high-definition scene cam-era. A Simulab Boss knot tying board (Seattle, WA)was used for the pretest and retention, with bluemarkers indicating the location of desired knotplacement on the parallel tubing at a separationwidth of 4 cm. An Ethicon knot tying board(Somerville, NJ) was used for the transfer, with ared marker indicating the location of desired knotplacement at the center of the hook, which wassurrounded by a cylinder (Fig 1). Both boards werecovered with surgical drapes. Ethicon 2-0 Perma-hand silk sutures were used throughout the testingsession. A Polar RX300 heart rate monitor (LakeSuccess, NY) was used to assess changes in heartrate variability between anxiety conditions.

Procedure. All participants completed a pretestand a training phase followed by simple andcomplex retention tests under conditions of highand low anxiety. In all conditions, participantswere required to tie 1-handed square knots with3 throws. Before the testing session, participantswere fitted with the SMI-ETG system and cali-brated. The experimental procedure is outlinedin Table I. In the pretest, participants wererequired to tie 3 separate knots at the knot place-ment location on the tubing. Participants thencompleted a 5-step training program. For step 1,participants in both groups viewed an Ethicontraining video on the 1-handed square knot, whichemphasized the correct movements of the handsand suture. In step 2, participants in the TT groupwere provided with additional technical instruc-tions taken from the Ethicon knot tying manual,whereas the QET group was provided with QE

Fig 1. (A) Simulab Boss knot tying board, used for thepretest and retention, with markers indicating desiredlocation of knot placement. (B) Ethicon knot tying cylin-der used for the transfer test, with marker indicatinglocation of desired knot placement at the center of thehook. The black circle indicates where the participantis looking.

SurgeryVolume 156, Number 5

Causer et al 1091

instruction, which emphasized a long QE durationon the placement location before each throw.13

For step 3, participants in the QET group vieweda video of an expert surgeon using a long QE dura-tion on the placement location, and were encour-aged to adopt this behavior. The TT groupviewed the same video with the gaze cursorremoved; thus, only the hand and suture move-ments were visible. In step 4, participants vieweda video of themselves recorded during the pretestand comparisons were made with the expertmodel. The TT group viewed their hand move-ments and further feedback on hand movementswas provided; in contrast, the QET group vieweda video showing where they were looking duringthe task, with additional instruction to adopt along QE duration on the placement location. Forstep 5, participants completed 3 more practiceknots. Steps 2–5 took approximately 5 minuteseach and were repeated subsequently twice, withparticipant videos updated in each phase.

Post-training participants were required to tie 3knots in simple (same as pretest; Fig 1, A) andcomplex (the hook inside the cylinder; Fig 1, B)retention tests under conditions of low and highanxiety. These took place 10 minutes after thetraining. In the low-anxiety condition, participantswere told that the trials were for calibration pur-poses and would not be compared with other par-ticipants. In the high-anxiety condition, severalego stressors were used to manipulate anxiety,which have been validated in previous research.4,14

Being videotaped for assessment purposes in-creases anxiety and decreases performance.4 Avideo camera was positioned directly in front ofthe participants, and they were informed that theircourse instructors would assess the knots. Partici-pants were told that a ranking system betweentheir peers would be created based on their knottying performance, and they were given noncon-tingent feedback that their current performancewas in the bottom 25%.23 Data collection tookapproximately 60 minutes.

Data management. For each participant, thesecond knot from each condition was analyzed,for a total of 100 knots. Each knot consisted of 3throws and 3 movement phases (cross, pass, andplacement). Data were coded using the Quiet EyeSolutions software (Calgary, CA), which couplesautomatically the gaze and hand movements anddetermines total fixations, QE duration, and move-ment time. Dependent variables were knot tyingperformance (%), heart rate variability (ms), per-centage QE duration (%), number of fixations,and total movement time (s). Total movementtime was defined as the start of the first cross phaseuntil the end of the final placement phase. QEduration was converted to relative time based onpercentage of total movement time. A fixation wasdefined as a stable gaze within 18 of visual angle fora minimum of 100 ms. The QE was defined as finalfixation on the knot placement location beforeeach placement phase. Two independent coderscarried out coding, with the objectivity of the databeing established using intraobserver (99.0%) andinterobserver (98.1%) agreement methods. Knottying performance was assessed by an expert sur-geon using the Tytherleigh instrument,24 which al-lows a maximum score of 13 per knot, which wasconverted to a percentage score.

Statistical analysis. Knot tying performance, QEduration, number of fixations, and total movementtime were analyzed using separate 2 3 5 mixeddesign analyses of variance (ANOVAs), with group(QET, TT) as the between-subjects factor andcondition (pretest, simple low anxiety, simplehigh anxiety, complex low anxiety, complex highanxiety) as the within-groups factor. Heart ratevariability was analyzed using a 2 3 2 mixed designANOVA, with group (QET, TT) as the between-subject factor and anxiety (low anxiety, highanxiety) as the within-subjects factor. Effect sizeswere calculated using partial eta squared values(hp

2). The alpha level for significance was set at0.05 with Bonferroni adjustment to control fortype 1 errors. Data presented in parentheses aremean values and standard error of the mean.

Table I. Experimental procedure for the quiet eye and technical training groups

Stage Quiet eye training Technical training

Pretest Three separate knots at the knot placement location on the tubing (Fig 1, A)Training phase

(approx. 60 min)1. Viewed standardised Ethicon training video (5 min)2. Provided with quiet eye instruction based

on previous literature (5 min)Provided with technical instruction based on

Ethicon manual (5 min)3. Viewed video of an expert surgeon’s QE

during a knot tying procedure (5 min)Viewed video of an expert surgeon’s hand

movements during a knot tying procedure(5 min)

4. Viewed a video of themselves from thepretest to compare their QE to theexpert’s (5 min)

Viewed a video of themselves from the pretestto compare hand movements to theexpert’s (5 min)

5. Three practice knotsRepeat steps 1–5 twice more (Videos in step 4 updated after each training phase)

Simple low anxiety Three separate knots at the knot placement location on the tubing (Fig 1, A)Complex low anxiety Three separate knots at the knot placement location on the hook (Fig 1, B)Simple high anxiety Three separate knots at the knot placement location on the tubing (Fig 1, A)Complex high anxiety Three separate knots at the knot placement location on the hook (Fig 1, B)

SurgeryNovember 2014

1092 Causer et al

RESULTS

Group and condition main effects for all AN-OVAs are reported in Tables II and III, respectively.

Knot tying performance (%). The ANOVArevealed a group by condition interaction (F4,72,= 2.78; P = .03; hP

2 = 0.13; Fig 2). As predicted,both the QET and TT groups significantlyincreased their knot tying performance from pre-test to the low anxiety conditions (P < .05).Although the QET group maintained performanceunder the high-anxiety conditions, the TT groupperformance decreased to pretest levels. These re-sults suggest that the QET group had developed astrategy that enabled them to maintain perfor-mance, even under high-anxiety conditions,whereas the performance of the TT groupdeteriorated.

Heart rate variability (ms). The beat-to-beatfluctuation of the heart rhythm decreases underconditions that require increased mental effortand/or during anxiety inducing situations owingto changes in the baroreflex blood pressure con-trol subsystem.25 In the current study, we measuredheart rate variability to ensure that our anxietymanipulation was effective. A lower heart rate vari-ability is indicative of an increase in anxiety. As pre-dicted, participants had less heart rate variability inthe high-anxiety condition (748 ± 26 ms)compared with the low-anxiety condition (818 ±29 ms; F1,18, = 36.25; P < .001; hP

2 = 0.67). As ex-pected, there were no between-group differences(P > .05). These data provide evidence that theanxiety manipulation was successful.

Quiet eye duration (%). The ANOVA showed agroup by condition interaction (F4,72, = 5.91; P <.001; hP

2 = 0.25; Fig 3). The QET group increasedtheir QE duration significantly from pretest (9 ±3%) to the low-anxiety conditions (P < .05), andmaintained a significant improvement in thehigh-anxiety conditions (P < .05). In contrast, theTT group reduced their QE duration from pretestto the 2 complex conditions (P < .05), with no dif-ferences between pretest and either of the simpleconditions (P > .05). These data demonstratethat the gaze behavior of the TT became less effi-cient in the complex conditions, whereas thedata suggest that the strategy of the QET groupwas more robust, even under high anxiety andincreased complexity.

Number of fixations. The QET group decreasedthe number of fixations from pretest to allpost-training conditions (P < .05; Fig 4). ANOVArevealed a group by condition interaction(F4,72, = 8.13; P < .001; hP

2 = 0.31). The TT groupdemonstrated no differences in the number of fix-ations between the pretest and simple low-anxietycondition (P > .05); however, there was an increasein number of fixations from the pretest to bothhigh-anxiety and complex conditions (P < .05).The TT group increased fixations as thecomplexity and anxiety increased, which is indica-tive of a less efficient strategy susceptible to distrac-tions. In contrast, the QET group maintained amore efficient strategy post training, which seemedto enable them to cope with the increased process-ing demands in the complex condition.

Table II. Group main effects from analysis of variance for the main dependent variables

Dependent variable Quiet eye training Technical training F value P value hp2

Knot tying performance (% ± SEM) 77.7 ± 2.0 69.1 ± 1.8* 16.86 <.001 0.55Quiet eye duration (% ± SEM) 34.2 ± 4.5 7.6 ± 1.0* 25.90 <.001 0.59Number of fixations (± SEM ) 9 ± 1 23 ± 2* 21.36 <.001 0.54Total movement time (s ± SEM) 16.5 ± 0.7 20.4 ± 0.9* 8.25 .009 0.32

*Significantly different to quiet eye training group.SEM, Standard error of the mean.

Table III. Condition main effects from analysis of variance for all main dependent variables

Dependent variable PretestSimple lowanxiety

Simple highanxiety

Complex lowanxiety

Complex highanxiety

Fvalue P value hp

2

Knot tying performance(% ± SEM)

60.4 ± 1.2 87.0 ± 2.6* 79.2 ± 2.7* 71.5 ± 2.6*,y 68.8 ± 2.8*,y,z 21.96 <.001 0.55

Quiet eye duration (% ± SEM) 10.6 ± 2.2 35.0 ± 8.3* 22.0 ± 5.6 22.6 ± 5.6 14.4 ± 2.4 4.95 <.001 0.22Number of fixations (± SEM) 18 ± 2 12 ± 2* 17 ± 3y 15 ± 2 19 ± 3y 5.13 <.001 0.22Total movement time (s ± SEM) 16.7 ± 1.3 15.2 ± 0.9 20.7 ± 1.4y 17.1 ± 0.9 22.7 ± 1.6*,y,x 8.56 <.001 0.32

*Significantly different to pretest.ySignificantly different to simple low anxiety.zSignificantly different to complex low anxiety.xSignificantly different to simple high anxiety.SEM, Standard error of the mean.

Fig 2. Knot tying performance (mean % ± SEM) for thequiet eye (QET) and technical training (TT) groups inthe pretest and simple and complex conditions underhigh and low anxiety (*QET versus TT; P < .05).

Fig 3. Quiet eye duration (mean % ± SEM) for the quieteye (QET) and technical training (TT) groups in thepretest and simple and complex conditions under highand low anxiety (*QET versus TT, P < .05).

SurgeryVolume 156, Number 5

Causer et al 1093

Total movement time (s). Participants in theQET group reported a faster total movement timecompared with the TT group (P < .05; Fig 5). Totalmovement time was significantly slower in the com-plex high anxiety condition compared with pretestand all other post-training conditions (P < .05).These data indicate that the QET led indirectlyto a faster movement time compared with the TTgroup. Increases in total movement times are ex-pected in more complex conditions owing toincreased programming demands. There was nogroup by condition interaction.

DISCUSSION

The aim of the study was to examine whether aQET or TT program would lead to increasedperformance in knot tying in 1-handed squareknots among first-year surgery residents underconditions of high and low anxiety, as well assimple and complex conditions. We hypothesizedthat the QET and TT groups would increase theirknot tying performance from pretest to all post-training conditions. The QET group woulddemonstrate more efficient gaze behaviors posttraining, as indexed by longer QE durations and

Fig 5. Total movement time (mean s ± SEM) for thequiet eye (QET) and technical training (TT) groups inthe pretest and simple and complex conditions underhigh and low anxiety (*QET versus TT, P < .05)

Fig 4. Number of fixations (mean ± SEM) for the quieteye (QET) and technical training (TT) groups in thepretest and simple and complex conditions under highand low anxiety (*QET versus TT, P < .05).

SurgeryNovember 2014

1094 Causer et al

fewer fixations. These improvements were ex-pected to be maintained in the QET group inthe high-anxiety conditions, with a decrement inthese metrics predicted for the TT group.

Knot tying performance significantly increasedfrom pretest to both low-anxiety conditions.Although the QET group improved their perfor-mance significantly more than the TT group, thesedata demonstrate that bothQETandTT techniquesare effective methods of training knot tying. Thesefindings support literature from other domains thathave indicated the effectiveness of training QE andthe association between longer QE and successfulperformance.3,21,26-28When trainingQE, it is impor-tant to develop similar cognitive processes andknowledge structures exhibited by experts19; thisensures that critical information defined by expertsis used to make decisions and execute actions,leading to a more efficient and effective strategyto improve skills. This strategy of attending tothe salient information at critical times, and cogni-tively ‘‘slowing down’’29 during these critical phasesis enhanced in the QE condition enabling

improvements in knot tying performance, but alsocould lead to more precise knot placement andpotentially lower error rates. This is imperativebecause incorrectly placed sutures may result in aknot slippage, unintentional shear force, or undueischemia of tissue, which can lead to knot failureand postoperative hemorrhage.30,31

Previous research has highlighted the paucity ofresearch into the effect of anxiety on surgical skills,and also the lack of formal training to overcomethese effects.18 Despite both groups improving theirknot tying performance from pretest to the low-anxiety conditions, only theQET groupmaintainedtheir knot tying performance under conditions ofhigh anxiety; performance of the TT group signifi-cantly decreased close to pretest levels. These datasuggest that the mechanisms developed in theQET intervention enabled participants to decreasethe negative effects of anxiety through mainte-nance of their QE focus on the knot placement loca-tion, rather than on the mechanics of knot tyingand handmotion, which constituted the instructionfor the TT. Directing gaze to critical target locationsduring a movement may be beneficial in severalways. First, it may provide a single relevant pointof focus around which movements and actions canbe orientated. Second, it may enable the partici-pants to control their emotional state through theuse of a long duration QE focus that is continuallyrelevant to the task. Third, it may limit the amountof erroneous information processed from the envi-ronment, allowing the participant to attend selec-tively to the information critical to successfulperformance; this training also enables the partici-pant to use coping strategies to overcome the stress-ful environment. During an operation, thisincreased QE may not only increase performanceon the primary task, but also free up processing re-sources to deal with other information sources, orfor communication between the surgical team.

As we would expect, those participants in theQET group demonstrated more efficient visualstrategies as evidenced by significantly longer QEdurations and fewer fixations compared with theTT group. When the eyes move from 1 fixationlocation to another using rapid eye movementscalled saccades, visual information is suppressed.Therefore, a greater number of short durationfixations decreases the amount of informationprocessed. Fixating more areas is a characteristicof novice eye movements. Usually, novices do notknow where the relevant cues are in a taskenvironment, and therefore use a greater numberof fixations to scan the whole environment.32 Thisstrategy deceases the amount of information they

SurgeryVolume 156, Number 5

Causer et al 1095

are accruing from the critical areas of the task,which leads to poorer execution. In the currentstudy, the QET group used fewer fixations oflonger duration, to the final placement locationof the knot, which seems to ensure placement ac-curacy and appropriate tension of the knot. Theseresults were exaggerated in the complex conditionunder high anxiety, when the demands of atten-tion were increased. These findings support theslowing down29 and other literature demonstratingthat engaging in more systematic strategies ofcognitive focus can enable performers to over-come the demands of anxiety-provokingscenarios.4

Our study highlights the importance of under-standing how technical skills are acquired, and howeven simple skills can break down under high-anxiety situations. During an operation, when slightmisjudgments or poor decision making can havecatastrophic consequences, the importance of allo-cating attention to critical cues and salient informa-tion at the relevant timepoints is essential.Our studyprovides evidence that with the correct training,surgeons can overcome the limits of attentionalcapacity, by employing strategies that highlight andrefocus attention during critical tasks.

Our study has several limitations. There was arelatively small sample size used in the currentstudy; future studies should look to identify differ-ences in training effectiveness with a larger sample,of different skill levels. Although we included atransfer condition (complex condition) in thisstudy, a more representative transfer shouldexamine tying knots or tracking knot tying perfor-mance in a live operation. Also, longitudinalstudies of resident education examining how thesetraining interventions impact on learning arerequired.

In conclusion, these data demonstrate theeffectiveness of training gaze behaviors, not onlyto improve the effectiveness and efficiency ofperformance, but also to mediate any negativeeffects of anxiety on performance. These findingshave important implications for medical educatorsand practitioners, as well as surgeons who may be(re)training or learning new procedures. Theemergence of advanced technologies in medicalsimulation provides an opportunity to acquiredifferent strategies to procure and measure tech-nical skills, without the risk to patient safety.21

REFERENCES

1. Eysenck MW, Calvo MG. Anxiety and performance: theprocessing efficiency theory. Cogn Emot 1992;6:409-34.

2. Eysenck MW, Derakshan N, Santos R, Calvo MG. Anxietyand cognitive performance: attentional control theory.Emotion 2007;7:336-53.

3. Causer J, Janelle CM, Vickers JN, Williams AM. Perceptualtraining: what can be trained? In: Hodges NJ, WilliamsAM, editors. Skill acquisition in sport: research, theoryand practice. London: Routledge; 2012. p. 306-24.

4. Causer J, Holmes PS, Smith NC, Williams AM. Anxiety,movement kinematics, and visual attention in elite-level per-formers. Emotion 2011;11:595-602.

5. Vickers JN. Control of visual attention during basketballfree throw. Am J Sports Med 1996;3:93-7.

6. Vickers JN. Advances in coupling perception and action:the quiet eye as a bidirectional link between gaze, attention,and action. Prog Brain Res 2009;174:279-88.

7. Causer J, Bennett SJ, Holmes PS, Janelle CM, Williams AM.Quiet eye duration and gun motion in elite shotgun shoot-ing. Med Sci Sports Exerc 2010;42:1599-608.

8. Vickers JN, Lewinski W. Performing under pressure: gazecontrol, decision making and shooting performance of eliteand rookie police officers. Hum Mov Sci 2011;31:101-17.

9. Ward P, Farrow D, Harris KR, Williams AM, Eccles DW,Ericsson KA. Training perceptual-cognitive skills: can sportpsychology research inform military decision training. MilPsychol 2008;20:S71-102.

10. Wilson M, McGrath J, Vine SJ, Brewer J, Defriend D, MastersR. Psychomotor control in a virtual laparoscopic surgerytraining environment: gaze control parameters differentiatenovices from experts. Surg Endosc 2010;24:2458-64.

11. Williams AM, Singer RN, Frehlich SG. Quiet eye duration,expertise, and task complexity in near and far aiming tasks.J Mot Behav 2002;34:197-207.

12. Harvey A, Vickers JN, Snelgrove R, Scott M, Morrison S.Expertise differences in performance and quiet eye dura-tion during identification and dissection of the recurrentlaryngeal nerve. Am J Surg 2014;207:187-93.

13. Vickers JN, Harvey A, Snelgrove R, Stewart A, MacKenzie C,Arsenault G. Expertise differences in quiet eye durationduring surgical knot tying. Int J Sport Psychol. In press.

14. Wilson M. From processing efficiency to attentional control:a mechanistic account of the anxiety-performance relation-ship. Int Rev Sport Exerc Psychol 2008;1:184-201.

15. Law B, Atkins MS, Kirkpatrick AE, Lomax AJ, Mackenzie CL.Eye gaze patterns differentiate novice and experts in a virtuallaparoscopic surgery training environment. In: Eye trackingresearch & applications symposium on eye tracking research& applications. New York: ACM Press; 2004. p. 41-8.

16. Zheng B, Tien G, Atkins SM, Swindells C, Tanin H, Mene-ghetti A, et al. Surgeon’s vigilance in the operating room.Am J Surg 2011;201:673-7.

17. Wilson MR, Vine SJ, Bright E, Masters RS, Defriend D,McGrath JS. Gaze training enhances laparoscopic technicalskill acquisition and multi-tasking performance: a random-ized, controlled study. Surg Endosc 2011;25:3731-9.

18. Wanzel KR, Kneebone R, Woloshynowych M, Nestel D,Moorthy K, Kidd J, et al. The effects of stress on surgical per-formance. Am J Surg 2006;191:5-10.

19. Causer J, Williams AM. Professional expertise in medicine.In: Lanzer P, editor. Catheter-based cardiovascular interven-tions – knowledge-based approach. New York: Springer;2012. p. 97-112.

20. Vine SJ, Masters RS, McGrath JS, Bright E, Wilson MR.Cheating experience: guiding novices to adopt the gazestrategies of experts expedites the learning of technicallaparoscopic skills. Surgery 2012;152:32-40.

SurgeryNovember 2014

1096 Causer et al

21. Causer J, Harvey A, Snelgrove R, Arsenault G, Vickers JN.Quiet eye training expedites surgical knot tying: a random-ized controlled study. Am J Surg 2014;208:171-7.

22. Causer J, Barach P, Williams AM. Expertise in medicine: us-ing the expert performance approach to improve simula-tion training. Med Educ 2014;48:115-23.

23. Wilson M, Vine SJ, Wood G. The influence of anxiety on vi-sual attentional control in basketball free throw shooting.J Sport Exerc Psychol 2009;31:152-68.

24. Tytherleigh MG, Bhatti TS, Watkins RM, Wilkins DC. Theassessment of surgical skills and a simple knot-tying exer-cise. Ann R Coll Surg Engl 2001;83:69-73.

25. BerntsonGG, Bigger JT, EckbergDL,GrossmanP, KaufmannPG, Malik M, et al. Heart rate variability: origins, methods,and interpretive caveats. Psychophysiology 1997;34:623-48.

26. Causer J, Holmes PS, Williams AM. Quiet eye training in avisuomotor control task. Med Sci Sports Exerc 2011;43:1042-9.

27. Harle SK, Vickers JN. Training quiet eye improves accu-racy in the basketball free throw. Sport Psychol 2001;15:289-305.

28. Vickers JN. In: Perception, cognition and decision training:the quiet eye in action. Champaign, IL: Human Kinetics;2007.

29. Moulton CA, Regehr G, Mylopoulos M, MacRae HM. Slow-ing down when you should: a new model of expert judg-ment. Acad Med 2007;82:S109-16.

30. Scott D, Scott LM, Howe BL. Training anticipation for inter-mediate tennis player. Behav Modif 1998;22:243-61.

31. Sosa JA, Bowman HM, Tielsch JM, Powe NR, Gordon TA,Udelsman R. The importance of surgeon experience forclinical and economic outcomes from thyroidectomy. AnnSurg 1998;228:320.

32. Mann DTY, Williams AM, Ward P, Janelle CM. Perceptual-cognitive expertise in sport: a meta-analysis. J Sport ExercPsychol 2007;29:457-78.