A Study on the Effect of Presence andImmersion in Aiding Memory Recall Ability

Lizzet Clifton∗

Duke UniversityAnuraadhaa Kandadai†

Duke University

ABSTRACT

Immersion in a Virtual Environment is defined by the technologythat was used to create that VE. It helps to create the feeling of pres-ence or the sensation of being there. As the fields of gaming andVirtual Reality rapidly evolve, we have seen the transformation ofimmersive experiences become more and more realistic, presentinghigher levels of fidelity. Past research has shown that an increasedlevel of immersion from a Virtual Environment would be beneficialto the memory recall abilities of VR users, relative to a 2-D dis-play. However, due to the conflicts existing in previous work andthe lack of clear proof of the relation between sense of presenceand immersion with memory recall, we believe that research on thejoint influence of immersion and presence on recall is missing. Theaim of our research study was to examine if differing levels of im-mersion in a Virtual Environment affects ones sense of presenceand, thus, their ability in accurately and rapidly recalling informa-tion from a procedural task. We hypothesized that higher presencewould lead to higher recall accuracy and faster recall time. We con-ducted an experiment that compared the results of two VEs withdiffering levels of immersion when users were asked to recall infor-mation from a procedural task. The results from the Mann Whitneytest analysis on our study data suggest that there is no statisticallysignificant difference in both ingredients recall as well as recipe re-call when comparing a high-immersion virtual environment and alow-immersion virtual environment. However, the mean and themedian scores for both recall assessment scores is slightly higher incase of high immersion environment.

Index Terms: Immersion, Visual Fidelity, Sense of Presence,Memory Recall

1 INTRODUCTION

Virtual Reality is becoming more and more realistic every day. Asthe capabilities of VR and AR (Augmented Reality) such as navi-gation techniques, computer graphics, user-centered design, framerate speeds, and computer graphics continue to shoot forward, thepossibilities for the real-life applications of these technologies growendless. These technologies are becoming more sophisticated andmore intelligent, but there is not enough research being done on thebenefits that VR can have as a cognitive aid for education and train-ing purposes. One question that needs to be more closely lookedat is how much level of immersivity affects the outcome of VirtualReality as a tool for such enterprises.

We know that VRs displays allow us to use spatial and visualcues to better recall information when compared to a 2-D displaybecause it reduces the mismatch of our virtual world and our phys-ical perceptions. Our questions are:

1. How crucial is the feeling of presence?

∗e-mail:lizzet.clifton@duke.edu†e-mail:anuraadhaa.kandadai@duke.edu

2. If the subjects do not feel present in the environment, willtheir recall abilities change?

The goal of our user study was to examine how significant thesensation of presence in a virtual environment is in aiding recall.Slater defines immersion as the objective level of fidelity of the sen-sory stimuli produced by a VR system [14]. Furthermore, the termimmersion depends on the technology that was used to produce thevirtual environment. It is not the same as a sense of presence, how-ever, immersion does affect a users sense of presence. Presenceis often considered to be psychological, and it can only be experi-enced. This aspect makes the feeling of being there more challeng-ing to measure. Immersion is the degree to which the technologycan project the stimuli onto the users. Technology plays a signifi-cant role in immersion whereas presence merely is being immersedin the Virtual Environment. Highly immersive environments cancreate a feeling of presence, but it is not always the case. In ourstudy, by creating two Virtual Environments with varying levels ofimmersion which in turn would induce different levels of presence,we studied the effects of presence in aiding memory recall.

Previous studies have shown that an immersive virtual environ-ment allows the user to memorize a procedure more accurately thana typical 2D desktop display because the steps in the activity can bemapped to locations within a 3D environment. This approach relieson ”Method of Loci,” which is a memorization technique whichmaps tasks or visualizations to spatial memory to more efficientlyrecall it later on. The user mentally travels through the predefinedpath and uses details about the objects and their surroundings tocreate an association.

In our study, we want to examine the memorization of a procedu-ral task of creating and memorizing the steps in a recipe. We will betesting the effects of level of immersion in the ability to recall thisprocedure. In this study, we are considering the level of immersionto affect the level of presence a participant will feel, and thereforeaffect the ability to recall information.

2 RELATED WORK

Measuring presence is a difficult task to do given the psychologicalnature; however, the use of presence questionnaire was proposed tomeasure[16]. Presence questionnaire(PQ) is to measure the degreeof immersiveness of the individuals. Immersive Tendencies Ques-tionnaire (ITQ) is also another metric of presence which measuresthe capability individuals to be involved or immersed. Both PQ andITQ are a set of questions which use a 7-point scale with varyingdescriptions. In the majority of the studies involving presence, PQis being used. For this study, we intend to design a PQ related toour virtual environment(VE).

Memory can be classified into two- semantic and episodic. Se-mantic memory is the memory of concepts and facts, and episodicmemory is the memory of events. There are different memorytests- factual, recognition, brand preference and confidence in brandpreference[7]. Nadia et al. use a memory test to measure the senseof presence in VE[12]. The paper focuses on factual memory andconfidence in brand preference. Factual memory testing is done byusing a questionnaire to test the extent to which the objects are re-membered. Confidence in brand preference measures the intensityalong with the direction of attitude. In this study, confidence in

brand preference is measured by asking the level of confidence bya 9-point Likert scale (Not Confident At All Very Confident) alongwith the answer.

Previous studies have explored the relationship between pres-ence and memory recall. J Bailey et al. conducted an experimentto measure the impact of virtual experiences on memory in real-world tasks[2]. In the study, both free and cued memory recall ofa narrative when immersed in the VE is tested. The findings ofthe study indicate a negative association which could be due to thedrain in cognitive resources caused by high presence. Mediatedarousal caused by high presence could also hinder memory. Thestudy also notes that the memory recall of specific details of thevirtual environment was high whereas recall of related informationoutside of the virtual world was low. K. Mania et al. discusses thereal vs. VE, comparing participants level of presence, task perfor-mance, and cognition state employed to complete a memory task[9]. The study compares different conditions (real, 3D desktop,HMD, and audio only) where it assumes HMD is more immersivethan 3D desktop and audio-only condition. Information recall andspatial recall were both tested by collecting data using question-naires after the session in VE. A questionnaire used to measure theassess the level of presence in every condition modified to fit theapplication was used.

Another study explores whether immersion aids recall in recall-ing virtual memory palaces[8]. Memory palaces is a techniqueused in recall where information, people are organized spatially.To check if immersion aids recall, a comparison is made between a2D desktop monitor and an HMD. It is tested by creating a virtualmemory palace and asked to recall the image given the location andalong with the confidence rating for the answer. Metrics used inthis study include recall accuracy which is the number of correctanswers, the number of skips which is the number of no answers.A comparison between the number of errors and confidence ratingis done which indicates the performance, as well as the confidencerating, was higher in the HMD condition.

In order to develop a VE closer to the reality, sensory cues areused to improve the level of presence. It is believed that the higherthe range of sensory cues provided, the greater sense of presenceis felt in the VE. Sensory cues such as tactile, olfactory, audio andvisual can be used to study the effect on presence[5]. Memory re-call of spatial layout, as well as object location, was tested whichindicated that the overall sense of presence in a VE could increasewith the addition of tactile and auditory cues. The study observesthat increasing the level of visual fidelity did not affect the levelof presence. In that case of other sensory cues, the cues either ex-isted, or they didnt whereas in case of visual fidelity there were twolevels of varying fidelity. Interaction with the VE is limited wherethe movement of the users is restricted since the users were onlyallowed to turn their heads and not physically move around in theroom.

D. A. Bowman et al. completed a study to test the hypothesisthat higher levels of immersion benefit tasks if the activity can bespatially mapped within a 3D environment[3]. The results of the2009 study supported their hypothesis. They conducted a study fora procedure memorization activity where a user in a VE was showna procedure involving several steps. The user was asked to rehearseand memorize the procedure, which required perception and inter-pretation of abstract information. As they were testing the level ofimmersion, they defined this level as being made up of the field ofview, the field of regard, and software field of view. Furthermore,they set up 6 conditions which controlled each of the three fields.The layout of this study is similar to the one for our study, as it willalso be testing levels of immersion with different conditions.

In the study entitled ”Quantifying the Benefits of Immersion forProcedural Training,” A. Sowndararajan et al. similarly hypothe-sized that a higher level of immersion helps users memorize the

complex procedure by providing enhanced spatial cues, leading tothe development of an accurate mental map that could be used asa memory aid[15]. Their independent variable was the level of im-mersion that the user perceived, and their constants across the studywere the input device, navigation technique, environment design,and task. Similarly to our study design, their dependent variablewas the time taken to recall each procedure and the numbers of er-rors in describing the procedure. Interestingly, this study designedits experiment in three phases. The first phase was the ”TrainingPhase,” in which the experimenter identified objects used in the pro-cedure and explained each step in detail. The second was the ”Prac-tice Phase,” in which the participants were asked to recall the pro-cedure verbally. The final phase was the ”Final Assessment Phase,”in which the participants were asked to recall the procedure with noaid from the experimenter. The results from the Final AssessmentPhase were used in calculating the accuracy and recall time of theparticipants. While this study gave more insight into the effects ofimmersion on memory recall ability, one criticism of it is that theexperiment consisted of two separate memorization tasks, meaningthat the participants had to go through all three phases twice. Thiscould have caused fatigue in the participants and could have madetheir recall abilities for the second task less accurate and slower.Another criticism of this study is that there were many variablesthat did not have separate conditions. The researchers tested FOV,software FOV, the field of regard, screen size, and screen shape.However, they are not sure which components had a positive effectsince they did not test them individually.

Capobianco et al. analysed the effects of egocentric and al-locentric spatialization and the impact of frame of reference,knowledge of architectural environment, and navigation on recallperformance[4]. They split their study into three different envi-ronments: two were egocentric and one was allocentric. The firstegocentric environment presented the participants with a series ofimages with no spatial information. It was simply a sequence ofimages one after the other. The second egocentric environment haditems appear one after the other following a circular shape aroundthe user. In this way, the participant could use the relationship oftheir location with the images as a point of reference for memo-rization. In the allocentric environment, a virtual apartment wascreated and a passive navigation technique was used. Images wereplaced in locations around the apartment. An interesting note aboutthis study is that the researchers chose abstract images as the im-ages the users had to memorize. This is because they did not wantthe participants to depend on other visual cues within the images tohelp them with their memorization. This is something that we willincorporate into our own study through the use of abstract ingre-dients in the recipe. Before the experiment began, the users wereintroduced to the idea of ”Method of Loci” and the researchers in-sisted that the participants would have to recall a list of items inorder. This was a very intriguing course of action taken by the re-searchers. They did this because they wanted to ensure that theparticipants used the environment and to reduce the number of cog-nitive strategies they could possibly use for memorization. This isanother strategy from this study that we will be incorporating intoour own. In their hypothesis, the researchers expected allocentricand egocentric environments to improve memory, when comparedto no surroundings, and be about equal in doing so. The results,however, showed that the use of an allocentric frame of referenceled to lower recall scores than the use of an egocentric frame ofreference and showed no improvement when compared to the envi-ronment in which no environmental information was given.

3 EXPERIMENT

We conducted a formal between-subjects study to investigate howvarying levels of immersion would induce different levels of pres-ence, and how these differing levels affected memory recall of a

procedural task. We chose to use between-subjects because wewanted to reduce learning effects that might cross over from mak-ing one recipe to another. We also reasoned that if someone wasfirst exposed to high-immersion environment, they would be moredisoriented if they were then placed into a low-immersion environ-ment. We trained participants on the procedural task of completinga recipe, and then compared the differences in performance fromthe two different levels of immersion.

3.1 HypothesisWhy should an increased sense of presence aid memory recall abil-ities? By using a virtual environment instead of a 2-D display, wealready know that memory recall abilities will have increased sincea user can use spatial information. In a similar train of thought, ahigher level of immersion should lead to a higher sense of presence,and thus, a greater sense of being there for the user. With richer,more detailed, and more sensory information available to the user,we believe that he or she will be able to use these extra details in theVirtual Environment to better recall the procedural task they will beasked to complete and memorize.

Our hypothesis is that the condition with the higher immersionwill result in the highest accuracy and fastest recall time for therecipe procedure. We believe this is true because of the increasedamount of immersivity and sense of presence that the user will feelin this condition, which will allow him or her to more intenselyuse the environment as a ”method of loci” while memorizing theprocedure.

3.2 Experimental DesignFor this experiment, we created two virtual environments and com-pleted a between-subjects study. We wanted to test a proceduraltask because completing and memorizing such a sequence of activ-ities would allow participants to have a clear goal in mind all whilebeing able to utilize the Method of Loci.

Because we wanted to test a procedural task, we decided to recre-ate a virtual kitchen, recipe, and ingredients for the user to interactwith. The procedural task itself would be the execution of a recipe.In order to prevent that a users prior knowledge of a recipe wouldaffect his or her memory recall, we created our own recipe fromingredients that were more generic and would not typically cometogether to create a soup dish.

The sequence of activities for the procedural task included read-ing a recipe and ingredients list, picking up and dropping the in-gredients and tools, slicing ingredients, opening cans, filling a potwith water, and placing the pot on a stove. In order to add anotherdimension of complexity to the recipe, we not only tasked the usersto memorize the steps and ingredients but also their colors and thequantities that the recipe called for. We designed the recipe to becomplex enough so that not everyone would remember all of it andnot so simple that everyone would remember every part. To get tothis balance, we came up with a recipe that consisted of 11 steps,contained 7 different ingredients, specified 5 different quantities,and included 4 different colors.

Environment A was the high-immersion environment and Envi-ronment B was the low-immersive environment. Which environ-ment a user experienced was the independent variable. For thetwo environments, we varied the details in the appearance of thekitchen and the level of audio stimulation. Environment A hadhighly-detailed architecture, ingredients, and textures and realis-tic auditory cues that played depending on which action the userwas completing. For example, the sound of the faucet would occurwhen the pot was being filled with water, the sound of water boil-ing would occur when the pot with water was left on the stove, thesound of slicing and chopping would occur when an ingredient wassliced, the sound of something dropping into water would occurwhen an ingredient was added to the pot, and a bell would go off

when the recipe was successfully completed. Environment B hadobjects with no textures except for solid colors, no visual details,and no auditory stimulation whatsoever. The recipe, ingredients,layout of the kitchen, navigation technique, and controllers wereour controlled variables and were identical in both environments.

The dependent variables were the following:1. The sense of presence that the user felt2. The time taken to orally recall the ingredients, their colors,

and their quantities and the accuracy of this assessment3. The time taken to write out all of the steps of the recipe in

order and the accuracy of this assessment

Figure 1: Low-Immersion Environment

Figure 2: High-Immersion Environment

3.3 Participants

For this study, we were able to recruit 18 unpaid participants andreserve times with them. Participants were required to be 18 yearsof age or older, to have no personal history of epilepsy, have no his-tory of severe simulator sickness, and to have normal or corrected-to-normal vision.

We randomly split those 18 people into Environment A or B,with each environment having 9 participants. However, only 13arrived at the lab on their reserved time and took part in the ex-periment. 8 were female and 5 were male. The mean age was 22years old. 7 participants had never used Virtual Reality before, 3of them reported having low experience with Virtual Reality, 2 ofthem reported having moderate experience with Virtual Reality, andnone reported having high experience with virtual reality. 7 of ourparticipants experienced the low-immersion environment.

3.4 Experimental Procedure

Before beginning the study, the participants were assured that theirparticipation was voluntary and that their identity as a participantwould remain anonymous and confidential during and after thestudy. We then gave them a written consent form that gave a briefoverview of the study and listed any possible associated risks andbenefits. The foreseeable physical risks included eyestrain, dizzi-ness, nausea, motion sickness and general discomfort during virtualreality tasks. If, after reading the form, they chose to continue withthe study, they were required to give their written consent in theform of a signature.

We then asked them to fill out a short demographics form thatincluded their age, gender, and experience level with virtual realityranging from None, Low, Moderate, to High. We continued withan explanation of the instructions for the study:

”The experiment will take place inside of a virtual environment.You will be wearing a head-mounted display and be holding twocontrollers in your hands. You will only be able to see the virtualenvironment and hear sounds from the virtual environment. You aretasked with reading the ingredients and instructions of a recipe andcompleting the recipe within 4 minutes, all while memorizing therecipe, the ingredients, their colors, and their quantities. In orderto grab an object, you place the controller on the object and holdthis trigger on the controllers. To release an object, you let go ofthe trigger. In order to slice any ingredient, you can place it onthe cutting board or use the can opener to open canned objects.All of the ingredients that you will need will be laid out on thecenter table. If at any moment you would like to exit the study,you can let us know as we will be able to hear you. Before theexperimental session begins, you will have 3 minutes inside of avirtual environment to familiarize yourself with the experience andcontrols. Do you have any questions at this time?”

At this point we assisted the participants in putting on the head-mounted display and grabbing hold of the controllers. They thenparticipated in the initial testing immersive environment. For theseenvironments, we had both a low-immersion environment and ahigh-immersion environment. If the participant had been placed inthe high-immersion experimental environment, they used the high-immersion testing environment and vice-versa. The testing envi-ronment took place in the same kitchen that we used for the exper-imental session and we placed a cutting board, can opener, a list ofdirections, and two cubes in the environment. We used the sameenvironment for the test and for the experiment so that participantscould practice using the navigation technique around the room. Weused two cubes to represent the ingredients, and the directions toldthe users to either slice or open the cubes with their respective tools.In this way, we ensured that lack of familiarity with the Virtual En-vironment’s controls would not hinder the participants performanceduring the experimental phase.

Once the testing immersion was over, the experimental immer-sion began. As soon as the experimental environment loaded, atimer began and the participant had 4 minutes to complete andmemorize the recipe. During this phase, we ensured that the HTCVive was always out of the way and the immersion area was clearso that the participants would not fall or injure themselves.

After the 4 minutes, the experimental phase concluded. TheHead-Mounted Displays were removed. The participants weregiven a post-test simulator sickness questionnaire and a presencequestionnaire. Then, they were asked to list off any ingredients,their colors, and quantities form the recipe that they remembered.They were timed. Following that, the participants were given ablank sheet of paper and asked to list all of the steps of the recipe,in order, as well as they could remember. They were timed.

Figure 3: Low-Immersion Testing Environment

Figure 4: Low-Immersion Experiment Environment

Figure 5: High-Immersion Testing Environment

Figure 6: High-Immersion Experiment Environment

3.5 Apparatus

We used an HTC Vive head-mounted display and its hand con-trollers for both environments. We programmed the environmentsusing C# in Unity. The study took place on Duke University’s Cam-

pus in Hudson 029D. Participants stood in the middle of the studyroom and were able to walk through the physical and virtual space.

4 RESULTS

The average recall performance of the participants in the high im-mersion (77.77778%) condition for ingredients recall was 6.34%higher than the low immersion condition (71.428%). In the case ofrecipe recall accuracy, the mean score is 2.70% higher in the high-immersion environment (73.484%) when compared to the low-immersion environment (70.77922%) The median recall accuracy

Figure 7: Accuracy percentage of ingredients recall score

in both the ingredients recall assessment as well as the recipe recallassessment was higher in the high-immersion environment. Themedian recipe recall scores were 77.272% vs 68.181% and medianingredients recall scores were 79.166% vs 75% in the high vs low-immersion environments. We used Mann Whitney Tests for both

Figure 8: Accuracy percentage of recipe recall score

tasks- the ingredient recall and the recipe recall. Mann WhitneyTest is a non-parametric test which is used to compare two groupswhere the assumption of normal distribution is relaxed. It is usedto test the null hypothesis by verifying if the distributions of bothgroups are identical. [1][13]

Here it is used test the null hypothesis that both theenvironments- high and low did not aid in memory recall for bothingredients and recipe. The Mann Whitney Test, or the Wilcoxon

test scores, was found to be W = 25, p-value = 0.6111(α = 0.05)for the ingredients recall assessment. With a p-value greater than0.05, there seems to be no significant statistical difference betweenmemory recall based on if the participant was placed in the highor low-immersion environment. For the recipe recall assessment,the Wilcoxon test scores was found to be W = 24.5, p-value =0.6643(α = 0.05). Again, with no significant statistical differencewe fail to reject the null hypothesis that the presence does not seemto aid recipe recall.

Figure 9: Average presence scores

The presence questionnaire was scored according to Witmer etal. [?] As shown in Figure 9, the average presence scores in thehigh-immersion Virtual Environment were higher than that of thepresence scores in the low-immersion Virtual Environment.

Since one of the differences between the high and low immersionenvironment is display fidelity, we also looked into the score ofrecalling the ingredient’s color along with the score of recalling theingredient’s quantity. In Figure 10, we can see that the averagescores for recalling color and quantity are slightly higher in the caseof the high-immersion environment. In comparing the color vs.quantity score, the color scores in both environments seem to behigher than the quantity scores.

In table 1, the time taken for the completion of the recipe forall participants is shown. As we can see, the difference in the av-erage recipe completion time is small, with the mean amount ofseconds for the high-immersion group being 183.1667 seconds andthe mean amount of seconds for the low-immersion group being182 seconds to complete the recipe.

Table 1: Comparison of percentages.

High Immersion Low Immersion

Participant No Time(in s) Participant No Time(in s)

2 175 1 1684 260 3 2086 112 5 2027 218 8 187

10 178 9 14712 156 11 126

13 236

Mean 183.1667 Mean 182

Figure 10: Average scores in quantity and color in Recipe recall

4.1 DiscussionWhen asked to report their experience level engaging with Vir-tual Reality, three participants reported a low level of experienceand two participants reported they had a moderate level of experi-ence with VR. Most of the participants (7 participants) had reportedthat they did not have prior experience with VR. The mean recipecompletion time for the category of low experience with VR was193.3333 seconds and the mean recipe completion time for the cat-egory of no experience with VR was 185.4286 seconds. As we cansee, the completion times for low experience and no experience areboth higher than the mean completion time for the moderate ex-perience category, which was 174 seconds. It is interesting to notethat the mean recipe completion time is greater in the no experiencecategory when compared to the low category. This could be due tothe fact that the number of participants who had reported no priorexperience with VR is higher than the number of participants whoreported low experience.

Our hypothesis was that, when a participant experiences a highlevel of immersion, it will lead to a greater sense of presence, whichwould aid in memory recall ability. The results from the MannWhitney test suggest that there is no statistically significant differ-ence in both the ingredients recall assessment as well as the reciperecall assessment between the two levels of immersion. However,the mean and the median scores for both scores seem to be higherin case of high-immersion environment.

When looking at the scores for ingredient color recall and ingre-dient quantity recall separately, one can expect the mean scores forcolor to be lesser than the mean scores for the quantity due to thedifference in display fidelity. However, the results indicate other-wise with the mean scores in color being higher than that of thequantity scores. This indicates that recalling a quantity seems tobe more difficult than recalling more visual, such as a color. Sinceour ingredients happen to be common vegetables and fruits, havingtextures on them do not seem to make a difference.

The presence questionnaire scores also indicate that the differ-ence between the sense of presence in a high-immersion environ-ment vs a low-immersion environment is very small. We did notexpect this and this may be due to fact that many of our participantsdid not have experience with Virtual Reality before, therefore theydid not know any other VE’s to compare the fidelity with.

In both the high and the low-immersion Virtual Environment’swe had placed additional ingredients in the scene other than theingredients in the recipe. For example, we included onions, redapples, and green tomatoes to the scene even though these were notpresent in the recipe. All participants except one did not confuse

any additional ingredients from the scene with ingredients from therecipe during the ingredients recall.

4.2 Conclusion

Overall, our study does not seem to indicate any statistical signif-icance that presence and immersion aid memory recall when com-paring two environments in virtual reality. However, as noted pre-viously, the mean and the median scores seem to indicate that theparticipants did perform slightly better with the accuracy of theirrecall after experiencing the high immersion environment. It is notenough of a difference, however, to reject our null hypothesis.

The task for completing the recipe in the experiment had 11steps. We do not believe that it is the case that this statistical in-significance could be due to the recipe being overly simple, as noneof the participants received a perfect or near-perfect score in re-calling the ingredients. Perhaps the true reason for the statisticalinsignificance could be that we only considered display fidelity andaudio stimulation as the differences between the two virtual envi-ronments. It might be worthwhile to consider adding other factorssuch as tactile feedback to the high immersion environment and adecreased Field of View to the low-immersion environment. Thiswould require multiple conditions with a variation of each of thesecombinations so that we could pinpoint exactly what technologyaffected the level of immersion.

ACKNOWLEDGEMENTS

The authors wish to thank Dr. Regis Kopper, an Assistant Re-search Professor of Mechanical Engineering and Materials Scienceat Dukes Pratt School of Engineering and the director of the Dukeimmersive Virtual Environment (DiVE) and Zekun Cao, a PhD Stu-dent in Mechanical Engineering at Duke University. This workwas supported in part by Duke University’s Computer Science 590Course: Advanced Topics in Computer Science, Virtual RealitySystems Research.

REFERENCES

[1] Mann-whitney u test in spss. https://statistics.laerd.com/premium-sample/mwut/mann-whitney-test-in-spss-2.php. Accessed: 2019.

[2] J. Bailey, J. N. Bailenson, A. S. Won, J. Flora, and K. C. Armel. Pres-ence and memory: Immersive virtual reality effects on cued recall.

[3] D. A. Bowman, A. Sowndararajan, E. D. Ragan, and R. Kopper.Higher levels of immersion improve procedure memorization perfor-mance, 2009.

[4] A. Capobianco, F. Larue, and T. Jund. Impact of frame of referenceon memorization in virtual environments, 2016.

[5] H. Q. Dinh, N. Walker, L. F. Hodges, C. Song, and A. Kobayashi.Evaluating the Importance of Multi-sensory Input on Memory and theSense of Presence in Virtual Environments. In VR, 1999.

[6] J. Jerald. The VR Book: Human-Centered Design for Virtual Reality.Association for Computing Machinery and Morgan & Claypool,New York, NY, USA, 2016.

[7] T. Kim and F. Biocca. Telepresence via Television: Two Dimensionsof Telepresence May Have Different Connections to Memory and Per-suasion. Journal of Computer-Mediated Communication, 3(2), Sept.1997.

[8] E. Krokos, C. Plaisant, and A. Varshney. Virtual memory palaces:immersion aids recall. Virtual Reality, May 2018.

[9] K. Mania and A. Chalmers. The effects of levels of immersion onmemory and presence in virtual environments: A reality centered ap-proach. CyberPsychology Behavior, 4(2):247264, 2001.

[10] K. Mania, A. Robinson, and K. R. Brandt. The effect of memoryschemas on object recognition in virtual environments, 2005.

[11] K. Mania, T. Troscianko, R. Hawkes, and A. Chalmers. Fidelitymetrics for virtual environment simulations based on spatial memoryawareness states, 2003.

[12] D. Nadia, M. Mohd, R. Dayang, and R. Awang. Subjective measure-ment of presence in image based virtual reality based on memory test

factors. In 2012 International Conference on Green and UbiquitousTechnology, pages 149–152, July 2012.

[13] Shier. Mann-whitney. http://www.statstutor.ac.uk/resources/uploaded/mannwhitney.pdf.Accessed: 2019.

[14] M. Slater. A note on presence terminology. Presence Connect, 3, 012003.

[15] A. Sowndararajan, R. Wang, and D. A. Bowman. Quantifying thebenefits of immersion for procedural training, 2008.

[16] B. G. Witmer and M. J. Singer. Measuring presence in virtual en-vironments: A presence questionnaire. Presence: Teleoperators andVirtual Environments, 7(3):225–240, 1998.