Method of Loci in VR Web Search:
Memory Retention Support byOrganizing Search Results in a VR Room
Yumiho Takeuchi⋆1 , Yoshiyuki Shoji1[0000−0002−7405−9270] , andMartin J. Dürst[0000−0001−7568−0766]
Aoyama Gakuin University
Sagamihara, Kanagawa 252-5258, Japan
takeuchi@sw.it.aoyama.ac.jp, shoji,duerst@it.aoyama.ac.jp

Abstract. This paper investigates whether the Method of Loci is also
effective for Web search in a VR environment. The Method of Loci (often called Mind Palace) is one of the most famous Mnemonic; whenmemorizing things, placing them in a building reproduced in the brain
makes them easier to recall. We implemented a browser that is movable
within the VR space, and VR rooms to verify whether such a Mnemonic
could be used for Web searches in VR. The subject experiment compared
four types of rooms: a Sequential-alignment room, a White room, a 4colored wall room, and a Realistic room with furniture. In each VR room,
users can freely create Web browser windows, and they can place, scale,tilt, and manage the windows anywhere in the room. Six participants
searched for many things, compared them, and decided on their opinions
in the VR room. The result shows that participants who searched inrealistic rooms remembered more details of their searches a week later.
Keywords: Virtual Reality · Web Search · Information Retrieval · Methodof Loci.

1

Introduction

With the rapid spread of VR (Virtual Reality) devices in recent years, opportunities for work to be performed in the VR space have increased. In addition toits original use for general game purposes, in an increasing number of cases, it isbeing used for practical software projects, such as construction use, events, andexperience-based training. VR has the ability to work even if the object itself
is not in that location, can return it to its original state immediately in caseof failure, and checks the results in a three-dimensional way. The use of VR isprogressing in a wide range of fields, such as education and training VR, since it
can also be used for training where there would otherwise be the risk of physicaldanger.
⋆Yumiho Takeuchi researched at Aoyama Gakuin University until 2021 but now works
at a company.

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Despite the VR space being so convenient and experience-based, unlike work
performed on a conventional computer screen, it has the disadvantage that it
is challenging to search while working. For example, when searching during VR
work, it is sometimes necessary to remove one’s head-mounted display and searchusing a separate computer or smartphone. Moreover, even if the search takes
place without removing the headset, it is necessary to close the software theworker was using and launch a search browser. Even if the search function isembedded within the VR space, it is necessary to input text and search in the
VR space, where it is difficult to carry out the input process. Although, inreality, it is possible to search on the spot using a smartphone or PC, current
VR technology has not yet developed to a state where it is possible to searchwith any level of comfort.
Several measures of resolution have been considered for resolving these kindsof issues relating to the difficulty of searching within the VR space. If we focus oncomplex issues surrounding the input of text, innovation regarding the following
is required:– Reducing the effort of input,– Reducing the frequency of text input, and– Reducing the number of searches itself.
We can broadly categorize these into two approaches: reducing the effort
required for input and making repeat searches unnecessary. Many studies havefocused on the approach of reducing the effort for input in the VR space andmaking text input a more comfortable process [1, 4, 11]. These include, for example, keyboards that make use of hand tracking [6]. With a software keyboardthat uses the pinch input format, a circle is made using the thumb and otherfingers, and this corresponds to the keyboard layout. With this format, as thesoftware displays vocabulary after judging the context, this enables text entry
at a low cost but has the feel of predictive text conversion. Methods have also
been conceived that can reduce the frequency of text input by using information
search technology, such as query recommendations. This kind of technology is
not limited to the VR space, and is commonly used for search engines in mobile
devices with complex text input.
On the other hand, however easy it is to enter text and however much theeffort of inputting text is alleviated, it does not change the fact that it is necessary
to suspend work to search while experiencing VR. The approach taken in thisstudy is to reduce the number of searches. The objective of conventional methods
has been to make input more comfortable when searching. On the other hand,
if the number of searches themselves can be reduced, this could provide anindirect solution to the complexity of searching in a VR environment. It has
been said that in Web searches carried out until now, most search queries arerepeat searches of information that has already been searched before. According
to a survey by Teevan [12], 40 percent of queries are repeat search queries.
If we can eliminate repeat searches, there will be an opportunity to perform
complicated procedures may be reduced by up to 40 percent, even if the text
input and search procedures are complicated in a VR environment.

Method of Loci in VR Web Search

3

In this study, therefore, we propose a method in which, by allowing the search
results to stay longer in the memory, we can eliminate the need to perform repeat
searches on content that has already been searched. When investigating multiple
items of information, the researched content does not easily become entrenchedin human memory.
This study focuses on a famous method, the Method of Loci (also called“Mind Palace” or “Memory Journey”), as a method of allowing the retrieved
contents to remain in memory for a more extended period of time. The Methodof Loci is a method of retaining people and objects in one’s mind by associating them. For example, consider the case that a person wants to memorize
the ingredients for dinner for shopping. When using the Method of Loci, theyfirst imagine their house in their mind. After that, they place the ingredientsfor appetizers in the entryway, the ones for the main dish in the living room,and the ones for dessert in their bedroom. Walk around that house and try tovisualize what they need to buy in each order. In this way, they are not justmemorizing words; people can also use their brain area for grasping space, making things easier to memorize and recall [7,9]. The aim, therefore, is to create anenvironment in which users can freely place search result Web pages in the VR
space and organize them by freely moving them around. Therefore, by linking
the search results in the VR space to places and organizing them in this way,
there are expectations that the Method of Loci can be used to remember the
results more effectively and reduce the number of searches during VR work.
The proposed method uses a Web browser that can search in the VR space,and make bookmark-like saves in the VR space. Figure 1 shows the actual screenshot of our system named the “Special bookmark”; a system that allows users tofreely arrange browsers on the space and organize search results. The following
VR rooms were created in order to verify what kind of space promotes memory
retention based on the Method of Loci (see Fig. 2):– Sequential Allainment room is a space that is just ordered like traditional
bookmarks,– White room is the user can freely allocate a browser in a spatial sense, but
the direction in which the user is facing is unclear,– Four-colered wall room is that the user can freely arrange the browser ina spatial sense, with painted walls on all four sides, and– Realistic room with furniture in which a variety of objects are placed, as
in a real room.
We conducted an experiment in which participants were asked actually toperform a retrieval task in each room. It makes it possible to verify what factors
aid in memory retention and the effectiveness of this method.

2

Related WorkIn this study, we proposed a method enabling better memory retention of search
results for a more practical method of searching in VR environments. Therefore,

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Fig. 1. A sample of a VR space where search result windows can be freely positioned.
A browser window can be placed anywhere in the room, at any angle, and scaled down
to any size.

this study is positioned in terms of an introduction to related research on Web
browsing support in VR and the retention of accessed information in memory.
2.1

Web Browsing Support in VR

Web browsing support exists as a measure to counteract the difficulties presented
when searching in a VR space. Among these difficulties, most studies have looked
at methods of reducing the effort required to input text in VR. Speicher et
al. [11] performed a comparative survey on six input methods. The results of
the investigation revealed that the input performance of the method of crucial
selection by pointing using VR controller ray casting is the optimal method.
Boletsis et al. [1] proposed a method in which text could be input by using
a controller as a drumstick and mapping the motion of a drum beating to thekey input. In this study, we aim to assist in accessing information in the VR
space at a different level from the comfort of text input and browsing. These
are interface improvements within the VR space so they can be used together
without modification.
2.2

Retention of Information in Memory

Many studies have looked at methods of retaining information in memory. In
studies by Bui et al., [3] and Einstein et al. [5], it was noted that powers ofmemory are improved by notetaking. Gordon et al. [2] elucidated the possibilityof strengthening memory related to one’s own concepts or episodes.

Method of Loci in VR Web Search

Sequential Alignment

White Room

The browser windows opened by the user

The user can place their browser windows

are automatically aligned. They have only

in a plain white room, but they can not

an order, not a position, which is the sameknow the direction.

5

as a conventional list-type bookmark.

4-colored Wall RoomRealistic Room

Users are free to put their browser

Users are free to put their browser window

windows in the room as they wish. The

in the room where their furniture is placed.

walls are painted in diﬀerent colors for

Furniture is concrete and easy to call by

east, west, north, and south, so they canname.

understand the direction in which they
have put their window.

Fig. 2. Four different interior rooms. Each has a different level of abstraction. Users
can put their search results windows in these rooms and organize them.

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There have also been studies linking VR space and memory. Krokos et al. [10]asked participants to perform memory-related tasks in a visually immersive VR
space, and verified that memory methods based on the Method of Loci could
be effective in the VR space. Through this experiment, it was noted that both
vestibular perception and cerebral reception help to retain things in memory. In
this study, the Method of Loci is applied more specifically in the VR space toresearch on a Web page to determine what kind of space is adequate.
On the other hand, Hine et al. [8] noted that in experiments using memory
with VR, this has a different impact on memory than in reality. In other words,
a gap was noted regarding the ease of retaining memory, based on active andpassive views. Elsewhere, Unsworth et al. [13] studied the influence of visual
fidelity and active navigation provided in a virtual environment. This study also
targets retrieval during VR games and works as a future application of thistechnology. When promoting this research in the future, it will be necessary to
fully consider the memories and impressions that are unique to the VR space.
In a study strongly related to ours, Yang et al. examine the effectivenessof memory palace methods in general tasks that can be placed within a VR
space [14]. Unlike their study, our research is a more localized, Web searchfocused analysis. For this reason, we compared four different rooms rather thana large-scale comparison of effects.

3“Spacial Bookmark” ApproachThis section describes the method proposed in this study. In this study, we
propose a method of memory retention based on the Method of Loci. Memory
retention is achieved by placing things to remember in space, and based on the
Method of Loci, the browser can be placed in the space freely reproduced in VR
and saved like a bookmark. We named it the “Spacial Bookmark” approach.
The search results can then be organized on the place in a VR space. At thistime, if the space in which the browser is placed in a white space without walls
or ceilings, it will be unclear where it has been placed, given that it will not
be possible to ascertain the eastern, western, northern, and southern directions.
Therefore, the browser was placed in a room with four colored walls. However,even with color within the space, it was very abstract and difficult to ascertain
the location. Therefore, the hypothesis was postulated that placing furnitureand the like within the space would create a location that could more easily be
expressed in words. To verify this hypothesis, we created three spaces based on
the proposed method and one space that reproduced the conventional bookmarks
within the VR space. Furthermore, when performing searches using these spaces,
we added a memory function to enable an analysis of the search behavior of theusers.
3.1

Overview of the Spatial Bookmark

In this study, we could organize the space by placing a screenshot of a Web page
within the space. Whereas bookmarks on a typical computer are represented as

Method of Loci in VR Web Search7

a list or a tree divided into folders, bookmarks here are stored as coordinates
within the space. The advantage of handling these kinds of bookmarks spatiallyin this way is that, based on the Method of Loci, it would be easier for the search
results to be retained in memory, and it would be possible to reduce the effort
required for repeat searches.
The Method of Loci is the method of memorization passed down since Ancient Roman times, and made famous by being summarized in the book “TheArt of Memory” in 1966 by Yates [15]. This method is also commonly referred
to as the memory palace method, the memory palace, or the journey method. In
this method, when memorizing items, a person imagine an arbitrary place, andlink the item they want to remember by placing the item in that place. At thistime, the place they imagine can be an actual place like their home, an imaginary
place, or even one of their body parts. It is thought that, as their memorize aplace and the item to remember as a pair in this way, there are more cues whenrecalling, and this makes it easier to recall things.
3.2

Creating Browser Placable in SpaceWe generated multiple browser windows within the space, and created an environment in which they could be placed freely. The user is able to move freely
within the environment and use the VR tracking device to generate a single
tabbed browser window at any location. The generated browser can then be left
at that location. In this way, it would appear as though the screenshot of thewebsite seen at that location is placed there as is, and after touching the browser
again, it would be possible to browse using that browser again.
The browser itself would have the same capabilities as conventional browsers,
but there would be certain restrictions for using multiple browsers within the VR
space. First, the “Back” button is allocated to one button on the controller, andall other navigation functions (i.e., Forward, Update, etc.) are excluded. The
concept is such that the user should access pages with individual informationfrom the search results page when actually searching, return to the search result
page if there is no information to be retained, and if there is information to beretained, place the entire window in the VR space and start a new window. The
Close button is excluded for the same reason. This is because we want the user
to overwrite and reuse windows other than those left as bookmarks within the
VR space. Further, as, on this occasion, the information search is being carriedout as the main task, we have yet to make it impossible to enter URLs directly.
Finally, when a link is clicked, a new tab is opened, so the function to open a
new window has been excluded. In this experiment, all browsers operate on asingle tab. This is because multiple windows are placed within the VR spaceinstead of opening multiple tabs within a single window.
When operating the browser on an actual VR device, the user wears VR
goggles by changing the direction of his/her face up, down, left, or right, and isable to walk around within the space to the extent allowed by the cable. The
browser operations are mainly operated with VR controls performed with both
hands. In addition to its position detection ability, in terms of the direction

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the controller is facing, the controller has three physical buttons enabled on thecontroller: a trigger that can be pulled with the index finger, a side button that
detects the user’s grip, and a touchpad button that can be operated using the
thumb. When the trigger is pressed, this has the role of the left click within thebrowser. This is also used when generating a new window or making active awindow that has already been generated. If the user presses the side button,
the user can grasp the browser window. The user can move the window in thegrasped state, and by releasing this grasp, place the window in the location of
their choice. As the controller is held in both hands at this time, they can grasp
the window with both hands, and stretch and shrink it, in order to expand or
contract the size of the window. By using this function, they can enlarge thewindow state when searching within the browser window and reduce it to asmall state when simply placed within the space. The touchpad in a thumbpress position was used as a physical button for detecting presses, rather thanas a touchpad. If they press the touchpad while operating the browser, they canmove one step back in the browser history.
3.3

Creating a VR Space to Spatial Bookmarks

Several spaces have been prepared to actually allocate windows for browsers
where it is possible to place windows as bookmarks within the created space.
The aim of this study is to determine the space that can best facilitate thememorization of retrieved content based on the Method of Loci. In the original
book on the Method of Loci by Yates, the space in which the object to beremembered is placed can be anywhere, such as a museum or a palace. However,within the VR space, as there are restrictions on physical movements as wellas mechanical restrictions, it is possible that the optimal space will change. For
example, a space where the user walks along a long route and places a memory
in each room would be difficult to reproduce with VR.
For this reason, in this study, we prepared the following three VR rooms inphases:– Most abstract space where the user can not know the direction,– Slightly less abstract space painted in four colors,– Space in which the place of allocation is expressed specifically in words,
and were able to organize the searches and results within the respective spaces.
We set the spaces to the same size to prevent any disparity between spaces.
Abstract Rooms We created two VR rooms in which users are able to simply
search and move the search browser within the VR space. These are the mostprimitive spaces for organizing information. In these spaces, the test participant
generated windows and searched in spaces that were nothing in particular andwere able to allocate the windows they liked to their favorite places within thespace.

Method of Loci in VR Web Search

9

The first abstract space is completely indistinguishable from front to backand left to right and is surrounded on all sides by pure white walls. The image ofthe actual space is shown in the upper right of Figure 2. It is possible to searchwithin this space, and place the search browser in the desired location, but as
the user does not know in which direction they are facing, the mutual placementof browsers is all relative. For this reason, even if they can remember somethingby saying “placed to the left on the previous page,” they cannot say “placed in
the western direction.”
The second space is a room like the first space, but with the concept of
direction added. An image of the actual room is shown in the bottom left of
Figure 2. In this room, the four walls are color-coded in four colors; red, blue,
yellow, and green. As a result, the browser is not simply relative, and also hasmeaning as an absolute position. In this space, the user can organize related
pages together by considering the direction, such as “Let us place pages related
to this topic in the direction of the red wall and pages related to different topics
in the direction of the blue wall,” which allows users to organize the information
based on direction.

Specific Room In addition to the two abstract spaces, a specific space basedon the motif of an actual room was prepared. An image of the actual space isshown in the bottom right of Figure 2. In this space, we can see a simple arrangement of furniture, with a bookshelf, bed, desk, and chair. In this space, thecoordinates, in addition to having a relative position, have an absolute position
as the azimuth, and also have fine-grained absolute positions, such as “placednear this furniture.”
The types of furniture placed in this space are limited to furniture where
the name easily comes to mind for whoever is looking at it. Other objects withmore difficult-to-recall names were not placed in said space. This is because thename of the furniture is thought to become a hint for people to more easily recall
where they placed things later.
In this space, it is possible to organize information in terms of where things
were placed, by linking to objects, in the form of “This perspective on this topic
is placed on the top-left of the TV” or “a perspective on a separate topic isplaced on the bed.”

Space Only Has Order The bookmarks in conventional browsers only haveorder and a hierarchical structure, and do not possess spatial coordinates. For
the purpose of comparative experiments, we created a space that reproduced
bookmarks with only order in the VR space. An image of the actual space isshown in the top left of Figure 2.
In this space, by pressing the Favorites button in a place where the user
wants to leave a bookmark, a new window opens next to the user. The user isable to continue searching by using this window. In this space, the user is notable to freely move the browser. For this reason, it can only remember in terms

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Y. Takeuchi et al.

of order within a series, in that a certain page is “bookmarked before that page”
or “was bookmarked first.”
3.4

Collecting Behavior Logs for Analysis

labelss:Log Operational logs remain for each search browser in the space. The
time, movement coordinates, and investigated URLs are recorded in the log. Elements recorded as time include the time that the Web browser was generated
and the time it was in the active state. When a browser is moved for the purpose of the organization, it records from where it was moved from and to andwhen. Finally, the URL actually accessed is recorded as the behavior within thebrowser.
Additionally, the screen actually seen by the user in the VR space can be
captured as video. By combining these three logs and screen captures, the user
can learn the browser’s behavior within the space, such as what kind of web
pages are opened and how they move.

4

Evaluation Experiment

We implemented the proposed method and evaluated each space through subject experiments to confirm in which space the search contents are most easily
remembered.
4.1

Implementation

We implemented the system using Unity to enable the browser to be placed
within the proposed VR space. The implementation used OpenVR and SteamVR.
In this experiment, we used HTC Vive and HTC Vive Cosmos, respectively, forthe experimental head mount displays. When implemented, room-scale tracking
was enabled, and this allowed the user to use the controller to actually physicallywalk and place the browser within the room without moving. For the browser
implementation, we used an Embedded Browser, generally sold as a Unity asset.
With the Embedded Browser, the Chromium browser for Desktop use can beused within the VR space. For the experiment, we restricted some functions; theuser cannot open multiple tabs in a single window, and cannot open menus.
The four spaces, including comparative methods, were reproduced in therespective VR spaces, and the following were implemented:– White Room is a space where the user can not know what direction they
are facing,– 4-colored wall room is a space separated into Four colors– Realistic room with furniture is a space in which the location can be easily
expressed in words, and– Sequential alignment is a space in which the browser is automatically placedin the horizontal direction.

Method of Loci in VR Web Search

11

6.8 meters
Wooden Desk

Cat Statue

6.4 meters

Wooden
Chair

Shelf

Initial Position of
User

Bed

TV on the Stand

Fig. 3. Layout view of the Realistic room. Objects that are easy to describe in words
are arranged around the user’s initial position.

The first White room is a space that is six meters long and two meters
high. It is square and surrounded by white walls, so the user cannot know what
direction they are facing. The 4 wall color space was also 6 meters long and 2
meters high, in the same way. The structure of the space itself is the same as inWhite, but the walls surrounding the four sides are painted red, blue, yellow,
and green, respectively. The space with furniture has a variety of furniture placed
within a room that is six meters long. As shown in Figure 3, objects such as aTV, bed, shelf, desk, and cat are placed inside the room.
The experiment with the participant was carried out in a specialist lab witha dedicated 6.4 x 8.6 m VR experiment space. An image of the experiment isshown in Figure 4. In terms of the setup for the actual experiment, HTC Vive
tracking sensors were placed three meters apart, and participants were free towalk between them in order to search the Web and organize the results.
4.2

Experiment Settings and Procedure

We evaluated the extent to which information could be retained over the longterm when linked to information when searching in the VR space. For this purpose, we requested that the six participants perform a search task in VR, collectlogs, and then go back to them one week later to check the extent of their recall regarding the search content. The time required for the search task was twohours per person.
The search task imposed on the test participants was to collect and organize awide range of information and, finally, provide a conclusion. The test participants

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Y. Takeuchi et al.

Fig. 4. Experiments were conducted in a room-scale VR environment of 6.8 x 6.4
meters using HTC VIVE.

finally performed decision-making based on the collected information and created
one ranking. Specifically, we first created a list of candidate Ferris wheels, suchas “the most suitable Ferris wheel for a date in Japan,” and then examined
the location and facilities of each the candidate Ferris wheels, and finally sorted
them in order of their suitability.
This kind of search task mimics typical search behavior in everyday life.
For example, let us suppose we buy a new smartphone. At that time, we always
choose which smartphone is best based on certain information we gather, such asimage quality and performance. In this way, natural search behavior is gathering
information when searching, examining, and selecting the information we want.
The actual experimental procedure is as follows: First, the test participant answers a questionnaire in advance regarding their method of performing searches
and whether he/she has used VR. Next, the test participant operates the proposed system for 30 minutes in order to become familiar with the VR operations, and freely perform Web browsing. Then, after a 30-minute break, he/she
performs search tasks in the four spaces over the course of one hour. After completing the search tasks, the test participants ranked their own search results
based on what they searched for and selected the top three results. Then, one
week later, they answered regarding what extent they remembered the top threerankings of the search results.
4.3

Experimental Task

In terms of a search task in which participants examine a large quantity of
information, discard certain information, and make decisions, a search task is
set in which they choose their top three, respectively from– Ferris wheel: Finding the best Ferris wheel considered to be appropriate
for dating in Japan, andMethod of Loci in VR Web Search

13

Table 1. Combination of a given experimental task and a VR room for each participant.
Considering order effects, each participant experiences the realistic room and one otherroom.
Participant ID Fisrt Task Second Task First Room Second Room
1
Ferrs Wheel Migration
Realistic
4-colored
2
Ferrs Wheel Migration
RealisticWhite
3
Ferrs Wheel Migration
Realistic
Sequential
4
Ferrs Wheel Migration 4-colored
Realistic
Ferrs Wheel Migration
White
Realistic
5
6
Ferrs Wheel Migration Sequential
Realistic
7
Migration Ferrs Wheel Realistic
4-colored
8
Migration Ferrs Wheel RealisticWhite
9
Migration Ferrs Wheel Realistic
Sequential
10
Migration Ferrs Wheel 4-colored
Realistic
11
Migration Ferrs Wheel
White
Realistic
12
Migration Ferrs Wheel Sequential
Realistic– Migration prefecture: Finding a prefecture in Kyushu (an area in Japan)
suitable for working and raising children if you move there when you are 30
years old.
It is not possible to create a ranking for these two tasks unless multiple
searches are performed. In the Ferris wheel task, participants were given an abstract search goal of finding the “most appropriate one for a date” and wererequired to go to multiple Ferris wheel-related Web sites in turn to find information on what they themselves considered appropriate for a date. In the migration
point task, based on the search goal of finding a place “appropriate for working
and raising children,” as part of this task, participants were asked to examine thesuitability of each of the Kyushu prefectures from various perspectives in termsof working and raising children. By comparing and examining information, they
finally create a ranking of the top three. The test participants were prohibitedfrom creating rankings by browsing only summary or ranking sites. This was toensure that they made their own decisions.

4.4

Experimental Participants

A combination of the four spaces was created, taking the order effect into consideration. Given that the superiority or inferiority of each method could not be
discussed without a minimum of twelve participants, we were only able to verify
the combinations represented in Table 1. When performing these tasks, an equal
number of test participants performed the proposed method first as the number
performing it later. Additionally, as there were two types of tasks and four typesof spaces, the 12 participants performed the tasks in an interchangeable order,that is to say, before and after the space and before and after the task.

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Y. Takeuchi et al.

Questionnaire on the Day and One Week Laterparticipants were asked to respond to the top three rankings in the search task
they performed for that day’s evaluation. In the evaluation, after one week had
passed, the test participants responded in regard to how much they recalled.
In addition to the ranking items, they answered in regard to whether they
could remember what information was placed where. They were also requested
to respond with how they were able to recall the information. In this way, it ispossible to judge the recall and reaffirmation. To confirm recall, they were asked
whether they recalled the rankings themselves. To confirm reaffirmation, they
were asked whether they remembered what was placed where.
4.6

Results of the Experiment

In this experiment, to measure to what extent it was entrenched in memory, it
was judged whether the rankings in the search task on the day in question and
one week later matched. In the experiment conducted on this occasion, the degreeof memory retention of the participants could not be assessed by ranking theretrieval tasks, and there were differences in the quality of how much information
they could recall. In regard to the i-th ranking element created in task t by test
participant u, the matching co(u, t, i) between the answer amorrow immediately
after the task and the answer one week later of alater is defined as(
1 : amorrow = alater ,(1)
0 : otherwise.
At this time, the extent to which the search results of task t are entrenchedin the memory of test participant u is expressed as the mean matching level:
ftask (t, u) =ranknumX
i=1

co(u, t, i).
ranknum(2)Here, this is set as ranknum = 3. If this value is summarized for each space
and the set of tasks carried out in this space r is expressed as T (r), this becomes:
X ftask (t, ut ).
|T (r)|(3)t∈T (r)At this time, the executor of the tasks carried out in this room is expressed asut .
As shown in Table 2, a space with Realistic room is able to support memory
retention better than a White space, but not as good as a room with 4-coloredwalls.
The number of people who remembered the place in which the information
was placed and the number of people who remember the information itself foreach space is shown in Table 3. The space in which the highest percentage

Method of Loci in VR Web Search

15

Table 2. Memory retention rate after one week for each VR room. Because participants
examined several candidates and answered the top three, it shows the correct answer
rate for each of their top three answers.
Room Type 1st 2nd 3rd Average
Realistic 0.91 0.83 0.91
4-colored 1.00 1.00 0.75
White
0.50 0.50 0.75
Sequential 0.75 0.75 0.75

0.89
0.91
0.58
0.75

Table 3. Details of what participants remembered after one week from the survey
evaluation
Room TypeRealistic
4-colored
White
Sequential

Location where they put browser What they searched for
Remembered
Forgotten
Remembered Forgatten
11
2
2
-

1
2
2
-

11
2
1
1

1
2
3
3

of participants who remembered all the information was found was the space
Realistic room with furniture, Furthermore, the Realistic room also had thehighest percentage of people who remembered what kind of information wasinvestigated.

5

Discussion

In this section, we focus on the four stages based on the experiment results, of
support for the retention of information in each space, VR familiarity, sequential
effects, and memory, and discuss whether the proposed method supports memory
retention. In general, there was a high degree of memorization of search results
one week later for all rooms. In regard to the memory task in the Realisticroom, although there was no particular trend toward higher memory retention
when taking the average of all test participants, there were differences in how
much detail of the retrieved results could be remembered.
First, we shall discuss the results of each method. In addition to having thesecond highest retention rate among all spaces, the space with Realistic room
had the highest percentage of participants who remembered the location in which
the information had been placed. When comparing Realistic room against theexisting method, the test participants moved more during the search. It is considered possible, therefore, that the physical movement of the participant’s body,as well as the difference in the space, may have impacted memory retention.
The following should be noted: Some test participants who experimented
with this combination used a unique memorization method of linking the information and words together. Specifically, in the Realistic room, they used word

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association to memorize the information and the furniture placement locations.
This is kind of a pun; such as “Kagoshima (the name of a prefecture) is in a
cage.” When using this method of memorization, whereas all the information researched in the Realistic room was remembered, some of the information in the
Sequential a space was forgotten. Having the user associate the VR space withthings that can be easily expressed using words is thought to enable effective
memory retention when the user associates the VR space with existing memory
methods such as word association.
The room with 4-colored wall had the highest memory retention among all
the spaces, but when asked whether they could remember the place where the information was placed and what information was searched, half of the respondents
answered that they could not. Compared to the Realistic room, many mademistakes when recalling the placement location. Specifically, the test participants
remembered where they had placed the information on the Ferris wheel that was
supposed to be in second place, and where they had placed the information on
the Ferris wheel that was in third place, but in reverse order.
Compared to all other spaces, the level of memory retention was lowest in
the White space. This may be because, compared to the Realistic room andthe 4-colored wall room, it was hard to summarize what had been placed andwhere. Specifically, one test participant placed a summary of all Ferris wheels
to his/her own right in the White space, but answered that he/she had put
the information for each Ferris wheel on his/her left side. They made a mistakewith the placement of information on the left and right, and this content was
not remembered in detail.
In the Sequential alignment space, in the majority of cases, the test participant did not remember the search results. This is thought to be because actions
could not be summarized without moving the browser, as in the Realistic room.
Specifically, if we focus on one test participant, in the migration point task, they
researched locations in terms of the three items of ease of working, the convenience of transportation, and positive effect on child-rearing. However, one week
later, they could not remember what kind of information they had researched.
On the other hand, if we focus on memory retention, the level of memory retention is not as high as the White space. This may have been because theact of active summarization in the White space was more burdensome from awork perspective, they focused more on the operation, and the result of this wasthat it was easier to focus on the information in the less intensive Sequentialalignment, making it easier to retain the information.
In terms of VR familiarity, all test participants responded that it was easierto perform the later task than the first task because they were familiar withthe operation. Given the effect of VR familiarity, it is possible that the later
results may be more easily retained in memory due to the effects of familiarity.
The majority of test participants had a higher level of memory retention forthe search task performed first than for the search task performed later. Someparticipants remembered information in more detail in the first search task thanin the later search task. As one of the test participants did not remember theMethod of Loci in VR Web Search

17

results of either task, if we consider that this participant should be excluded as
an outlier, the later search task did not produce abnormally high results. Basedon this, we can consider that the impact of VR familiarity is low.
It is also possible that the order effect may have impacted memory retention.
As many of the test participants were experiencing VR for the first time, thesearch results for the first task carried out may have remained particularly strong
in memory. In this experiment, the memory retention of the latter space of test
participants who experienced the Realistic room first was relatively low. It isthought that the search task conducted first had a greater freshness, and thismay have made a significant difference in the rankings. In addition, the test
participants who performed the Realistic room task later had greater memory
retention from the later search task than the earlier search task. For this reason,
it is considered that, though the order effect has an impact on the results, evenwhen considering the order effect, the Realistic room is thought to be able tosupport memory retention.
The aim of this study is to support memory retention. For this purpose, we
confirmed recall and reaffirmation in four stages. Recall was confirmed basedon whether the test participants could remember the ranking. However, in thisexperiment, there was no significant difference in memory accuracy among thetest participants in any of the spaces. This is thought to possibly be due tothe search task being simple on this occasion. As the top three items were the
top three items in the simple search task, there was no significant difference.
This was also more memorable due to the VR experience, which is somethingthat is not usually experienced. For this reason, it was not possible to determine
whether improved recall occurred with the present method in the Realistic
room. For reaffirmation, on the other hand, differences appeared between theRealistic room and the other spaces in terms of remembering the places information was placed and what information was searched. The places information
was placed were remembered more in the Realistic room than the other spaces,
and the searched information was remembered in more detail. More reaffirmationis thought to have occurred in the Realistic room than in the other rooms.
Based on this, it may be suggested that, although there was no significant
difference in the number of search results that could be recalled when considering
the possibility of memory support based on the Method of Loci, it may have had
an effect on the amount of content remembered.

6

Conclusion

This study proposed a Method of Loci -based method named “spatial bookmark”
for facilitating the recall of search results. It allows placing the search browserthat performs the search in the VR space by itself. Four rooms were createdwithin the VR space: a realistic room that could be easily expressed in words, aspace color-coded with four colors, a pure white space, and the Sequential space
like traditional bookmarks. An experiment was conducted in which participants
collected information from the Web and made a ranking. One week after the

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experiment, a survey was conducted regarding how much of the search content
was remembered, using a questionnaire. Based on the experiment results, it
was impossible to accurately measure the same day and next day evaluation of
the rankings due to the simplicity of the search task. However, the quality ofmemory retention differed between the spaces. Information was recalled the mostwhen searching in a room with 4-colored walls. The content of the information
researched in the Realistic room was remembered in detail, and the locationof placement was also remembered accurately. Finally, our study showed thepossibility of making users remember their searches by organizing the search
results in a non-abstract room.

Acknowledgements
This work was supported by JSPS KAKENHI Grants Number 21H03775, 21H03774,
and 22H03905. The research was also supported by ROIS NII Open Collaborative Research 2023 (Grant Number 22S1001).

References
1. Boletsis, C., Kongsvik, S.: Text Input in Virtual Reality: A Preliminary Evaluationof The Drum-like VR Keyboard. MDPI Technologies 7(2), 31 (2019)
2. Bower, G.H., Gilligan, S.G.: Remembering Information Related to One’s Self. Journal of research in personality 13(4), 420–432 (1979)
3. Bui, D.C., Myerson, J., Hale, S.: Note-Taking with Computers: Exploring Alternative Strategies for Improved Recall. Journal of Educational Psychology 105(2),299 (2013)
4. Carter, L., Potter, L.E.: Spatial Virtual Keyboard for Wand Based Virtual Reality.
In: Proceedings of the 5th Symposium on Spatial User Interaction. pp. 161–161(2017)
5. Einstein, G.O., Morris, J., Smith, S.: Note-Taking, Individual Differences, andMemory for Lecture Information. Journal of Educational psychology 77(5), 522(1985)
6. Fashimpaur, J., Kin, K., Longest, M.: Pinchtype: Text Entry for Virtual and Augmented Reality Using Comfortable Thumb to Fingertip Pinches. In: Extended
Abstracts of the 2020 CHI Conference on Human Factors in Computing Systems.
pp. 1–7 (2020)
7. Hartley, T., Lever, C., Burgess, N., O’Keefe, J.: Space in The Brain: How The
Hippocampal Formation Supports Spatial Cognition. Philosophical Transactionsof the Royal Society B: Biological Sciences 369(1635) (2014)
8. Hine, K., Tasaki, H.: Active View and Passive View in Virtual Reality Have Different Impacts on Memory and Impression. Frontiers in psychology 10 (2019)
9. Hok, V., Save, E., Lenck-Santini, P.P., Poucet, B.: Coding for Spatial Goals in
The Prelimbic/Infralimbic Area of The Rat Frontal Cortex. Proceedings of the
National Academy of Sciences 102(12), 4602–4607 (2005)
10. Krokos, E., Plaisant, C., Varshney, A.: Virtual Memory Palaces: Immersion aids
Recall. Virtual Reality 23(1), 1–15 (2019)

Method of Loci in VR Web Search

19

11. Speicher, M., Feit, A.M., Ziegler, P., Krüger, A.: Selection-based Text Entry in
Virtual Reality. In: Proceedings of the 2018 CHI Conference on Human Factors in
Computing Systems. pp. 1–13 (2018)
12. Teevan, J., Adar, E., Jones, R., Potts, M.A.: Information re-retrieval: Repeat
queries in yahoo’s logs. In: Proceedings of the 30th annual international ACM
SIGIR conference on Research and development in information retrieval. pp. 151–
158 (2007)
13. Unsworth, N., Engle, R.W.: The Nature of Individual Differences in Working Memory Capacity: Active Maintenance in Primary Memory and Controlled Search from
Secondary Memory. Psychological review 114(1), 104 (2007)
14. Yang, F., Qian, J., Novotny, J., Badre, D., Jackson, C.D., Laidlaw, D.H.: A virtual reality memory palace variant aids knowledge retrieval from scholarly articles.
IEEE Transactions on Visualization and Computer Graphics 27(12), 4359–4373(dec 2021)
15. Yates, F.A.: The Art of Memory, vol. 64. Random House (1992)