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Citation for published version:
Dag Sverre Syrdal, Kerstin Dautenhahn, Kheng Lee Koay, and
Wan Ching Ho, ‘Integrating Constrained Experiments in LongTerm Human–Robot Interaction Using Task- and Scenario-Based
Prototyping’, The Information Society, Vol. 31 (3): 265-283, May
2015.
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https://doi.org/10.1080/01972243.2015.1020212
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Integrating Constrained Experiments in Long-Term
Human–Robot Interaction Using Task- and ScenarioBased Prototyping
a
a
a
Dag Sverre Syrdal , Kerst in Daut enhahn , Kheng Lee Koay & Wan Ching Ho
a
a
Adapt ive Syst ems Research Group, School of Comput er Science, Universit y of
Hert f ordshire, Hat f ield, Unit ed Kingdom
Published online: 13 May 2015.
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The Information Society, 31:265–283, 2015
Published with license by Taylor & Francis
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DOI: 10.1080/01972243.2015.1020212
Integrating Constrained Experiments in Long-Term
Human–Robot Interaction Using Task- and ScenarioBased Prototyping
Dag Sverre Syrdal, Kerstin Dautenhahn, Kheng Lee Koay, and Wan Ching Ho
Downloaded by [University of Hertfordshire] at 03:35 02 June 2015
Adaptive Systems Research Group, School of Computer Science, University of Hertfordshire,
Hatfield, United Kingdom
In order to investigate how the use of robots may impact
everyday tasks, twelve participants in our study interacted with a
University of Hertfordshire Sunflower robot over a period of 8
weeks in the university’s Robot House. Participants performed two
constrained tasks, one physical and one cognitive, four times over
this period. Participant responses were recorded using a variety of
measures including the System Usability Scale and the NASA Task
Load Index. The use of the robot had an impact on the experienced
workload of the participants differently for the two tasks, and this
effect changed over time. In the physical task, there was evidence of
adaptation to the robot’s behavior. For the cognitive task, the use of
the robot was experienced as more frustrating in the later weeks.
Keywords
assistive robotics, domestic robots, human–robot interaction, prototyping
In the field of human–robot interaction, domestic,
human-centered environments present serious challenges
for prototyping human–machine interactions. In particular, when addressing future and emergent technologies, it
is a challenge to enable interactions that are situated in
such a way that they are meaningful to the user, and
allow users to translate this experience to their everyday
life. Moreover, the experience of such interactions is subjective, and the relationship between interactants,
Ó Dag Sverre Syrdal, Kerstin Dautenhahn, Kheng Lee Koay, and
Wan Ching Ho.
This is an Open Access article distributed under the terms of the
Creative Commons Attribution License (http://creativecommons.org/
licenses/by/3.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly
cited. The moral rights of the named authors have been asserted.
Received 28 December 2013; accepted 15 August 2014.
Address correspondence to Dag Sverre Syrdal, Adaptive Systems
Research Group, School of Computer Science, University of Hertfordshire, Hatfield AL10 9AB, United Kingdom. E-mail: d.s.syrdal@
herts.ac.uk
Color versions of one or more of the figures in the article can be
found online at www.tandfonline.com/utis.
technologies, and situations can be complex and dynamic
(Buchenau and Suri 2000). On the technical side, cuttingedge technologies often do not have the stability required
to function autonomously in an effective and safe manner
for sustained periods of time outside of highly constrained settings. However, such feedback is critical for
guiding the development of these technologies. This
necessitates a high degree of pragmatism and creativity
when developing appropriate methodologies for examining how prospective users interact with these technologies, and how these interactions may benefit or hinder
the user (Dautenhahn 2007).
While there have been studies of actual robots acting
autonomously in a domestic environment without continuous oversight by experimenters, either the robots
employed have had limited movement capabilities, and
served mainly as physically embodied conversational
agents (not unlike those described in Bickmore and Cassell 2005) as in the KSERA project (Payr 2010), or the
robots were market-ready products (Fernaeus et al.
2010; Sung et al. 2008) or at a late stage in the development cycle (Kidd and Breazeal 2008). Furthermore, due
to the cost in time and resources to set up and run the
experiments, live interactions with robotic technologies
in complex usage scenarios usually involve only a relatively small number of participants (Walters et al. 2011;
Huijnen et al. 2011). While it is often desirable to run
studies with the largest number of participants possible
for greater generalizability, there is also the need for
studies that allow for a wide range of interactions to capture data on human–robot interaction in all its richness.
This balance lies at the heart of our efforts to develop,
adapt, and use prototyping methodologies for domestic
human–robot interaction (Syrdal et al. 2008).
PROTOTYPING OF HUMAN–ROBOT INTERACTION
Broadly, there are two different approaches to prototyping
of human–robot interaction. The first one is a holistic,
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D. S. SYRDAL ET AL.
scenario-based approach (Carroll 2000), which takes a
high-level view of the situations and tries to capture the
experience of the interaction through narratives. Here the
participants’ interactions with the robot are framed within a
narrative that allows them to evaluate the potential impact
of the prototype in everyday life situations. These scenarios
can be presented to the participants as written stories
(Blythe and Wright 2006), videos (Walters et al. 2011; Syrdal et al. 2010), theater performances (Syrdal et al. 2011;
Chatley et al. 2010; Newell et al. 2006), or live human–
robot interactions (Koay et al. 2009). The second approach
is more reductionist and condenses and abstracts the salient
features of the interaction into a controlled experimental
setup. This approach has been used successfully for studying human–robot proxemics (Tapus et al. 2008; Koay et al.
2007; Dautenhahn et al. 2006), specific robot behavior
styles (Syrdal et al. 2009; Fussell et al. 2008; Bartneck
et al. 2005), and different user groups.
These two approaches are not mutually exclusive. For
instance, Walters et al. (2011) combined a high-level
narrative with a highly constrained experimental manipulation in a video study. However, each has clear strengths
and weaknesses when compared to the other. The narrative approach provides insights into how robotic technologies may impact on people’s lives on a more conceptual
level. It does not, however give the participant the clear
ability to experience and differentiate between the ways
that the particularities of a robot’s behavior or characteristics impact specific interactions. Highly controlled,
experimental studies, on the other hand, are often lacking
in ecological validity, but allow for in-depth understanding of specific aspects of the interaction.
The study presented here fruitfully brought together
both approaches: The controlled experiments were integrated with open-ended scenarios as part of a long-term
study (Syrdal et al. 2014). These studies were conducted
in the University of Hertfordshire Robot House.
UNIVERSITY OF HERTFORDSHIRE ROBOT HOUSE
The UH Robot House is a residential house, near the University of Hertfordshire campus, that has been adapted for
human–robot interaction studies. It has been augmented
into a “smart home” with low-cost, resource-efficient sensor systems that inform the robots about user activities and
other events in the environment (Duque et al. 2013).
Moreover, it offers ecological validity because it is a real
working house, with kitchen appliances, a TV, a doorbell,
and so on. Throughout the studies presented here, participants primarily used the living room, dining area, and
kitchen, sometimes responding to events (visitors, deliveries, etc.) at the front door, with an extra room used in the
briefing for the open-ended scenario. In general, the Robot
House serves as an effective test bed for prototyping
domestic human–robot interactions. Its infrastructure supports interactions with a range of robots such as the UH
Sunflower robot (Koay et al. 2013), PeopleBots (Walters
et al. 2011), and the IPA Care-O-Bot 3 (Parlitz et al.
2008; Koay et al. 2014).
CONSTRUCTED PERSONAS
Personas are understood in human–computer interaction
as fictional yet highly realized users of a given technology (Chang et al. 2008). By creating and extrapolating
behaviors, goals, histories, and characteristics of these, it
is possible to tightly focus the technological development. The specific personas used to guide the scenario
development in the Robot House were a couple in their
mid-to-late sixties. The personas were given work, interests, and health issues, which are summarized next.
The Husband (David) is recently retired from a whitecollar profession. He is looking forward to spend some
time focusing on his hobbies, which include reading,
watching documentaries, and building military models.
He has a heart condition, which requires him to take
medication regularly. For some reason, he often forgets
to take this medication and has to be reminded by his
wife daily. He also has a condition (likely arthritis in the
knees) that gives him some mobility issues.
The Wife (Judy) works from home most days. Her
husband’s recent retirement and associated distractions
are causing her some stress, and the couple some tension.
She normally stays in her home office almost exclusively
during her working hours, interacting with David primarily at mealtimes. She is used to computing technology,
relying on it to work effectively from her home office.
This has also enabled her and David to maintain close
contact (using Skype and other social media) with their
children and grandchildren.
Based on the lives of these personas, we created a
“typical” day comprised of episodes in which the robot
was utilized to aid “Judy” and “David” in their daily
activities. See Figures 1 and 2 for episodes from a scenario based on a “typical” day for the user personas. The
evaluation scenarios were created by examining the possible roles that the robot could play in the different episodes
that comprised a “typical” day for the two user personas.
This was done both as high-level narrative-based interactions, which presented scenarios where the interaction
with the robot was within a specific context for the participants, and through constrained and experimental examinations of the role of the robot within specific tasks.
OPEN-ENDED SCENARIOS
The open-ended scenarios sought to convey the impact of
the agent within a wider context to the participants in an
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LONG-TERM HUMAN–ROBOT INTERACTION
FIG. 1. Episode from a “Normal Day” for the user personas (1).
267
evaluation study. To achieve this, two open-ended scenarios were created. They were inspired by the Persona
Scenarios (as shown in Figure 1) but differed in that they
were intended for a single user, and would be meaningful
to an experimental participant within the context of a
1-hour duration interaction (for long-term studies a duration of 1 hour maximum for each session was considered
appropriate in order to avoid fatiguing the participants).
The scenarios were grounded in an imagined daily life,
with the robot adopting an assistive role: allowing the
participants to inform the robot about their preferences
in terms of drinks, snacks, leisure activities, and TV programs that they preferred. These elements were used in
individual episodes whereby each scenario was performed twice during the long-term studies, according to
the schedule shown in Table 1. In these episodes, the
participants were asked to engage in a structured roleplay-like scenario (Seland 2009) in order to investigate
the role of the robot in a manner that could be directly
related to the participants’ everyday experience.
FIG. 2. Episode from a “Normal Day” for the user personas (2).
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D. S. SYRDAL ET AL.
TABLE 1
Overview of sessions
Week
Week 1
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Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 10
Session content
Introduction to the Robot House,
familiarization with the robots and their
interface. Baseline experiment.
Review of Robot House, robots, and interface.
Repeat of experiment.
Open-ended scenario A
Open-ended scenario B
Repeat of experiment
Open-ended scenario A
Open-ended scenario B
Repeat of experiment
Debriefing
Note. The constrained experiment was run in Week 1 (2 tasks,
Human-only condition) and Weeks 2, 5, and 8 (two tasks, HumanOnly and Robot and Human conditions).
Therefore, they could directly experience the impact of
the robot. These scenarios also investigated particular
issues that were of interest to our research, such as
human and robot communication and “agent migration”
(see explanation in the following).
These scenarios were based around episodes in two
“imaginary” days and were intended to investigate
interactions with and responses to the robot in an
everyday setting. The first episode took place in the
“morning” and focused on the expressive capabilities
of the Sunflower robot. The second episode was set
during the “afternoon” and was focused on the participants’ impression of agent migration—the ability of
an agent’s “mind” to move between different robot and
virtual embodiments (Syrdal et al. 2009; Duffy et al.
2003). Here, the agent’s “mind” comprises its memory,
its interaction history, and a sense of context; for
example, it can remember the user’s preferences while
moving between different embodiments, and can continue tasks begun in one embodiment within another.
This allows the agent to take advantage of features and
functionalities of more than one embodiment while
maintaining the persistent features that make it unique
and recognizable from a user’s perspective. These
attributes include awareness of interaction history and
context, as well as persistent customizable features. In
the scenario, the migration took place between a Sunflower and a SONY Aibo robot. For both of these scenarios, participants were briefed as to the time of day
and the particulars of the situation they were going to
take part in (Koay et al. 2011).
CONSTRAINED EXPERIMENTS
Cognitive Prosthetic
The scenarios identified several instances in which the
robot companion would be able to assist the user by providing information. This information could be provided
in the form of reminders of appointments, mealtimes,
and medicines. In the chosen scenario the robot’s task
was to remind “David” to take his heart medication.
Adherence to a prescribed regimen of medication can
be difficult for many patients. Early approaches (as exemplified by Schwartz et al. 1962) presented this as being
caused by a shortfall in the ability of the patient, who was
seen as making mistakes. More recent approaches consider a wider range of reasons for nonadherence to prescribed medicine regimens. In addition to the cognitive
abilities of the patient, the new approaches also take into
account other factors such as the complexity of the medication schedule, perceived efficacy of the treatment, and
perceived risk of side effects (Horne et al. 2005).
While this particular scenario used the robot purely to
remind the user of his schedule in a manner similar to
that of cognitive prosthetics on hand-held platforms (Modayil et al. 2008), this functionality can also be combined
with more persuasive technologies that use relational and
other strategies in order to encourage habits conducive to
the health of the user (Bickmore et al. 2005). However,
this was not the focus of the current study, which focused
purely on the cognitive prosthetic aspect of such technologies and its impact within the performance of a task.
The experimental instantiation of the Cognitive Prosthetic task involved participants putting Scrabble tiles
into the correct spaces of a medicine dispenser on the living room table (see Figure 5, shown later), relying on a
master list that had to remain on the kitchen bench. There
were 28 spaces for the tiles, and both the position of the
tiles in the dispenser and their position on the list in the
kitchen were randomized.
Fetch and Carry
The Fetch and Carry task involved the carrying of objects
between different rooms. This task was performed during
episodes such as mealtimes, where the robot could assist
with the movement of prepared food from the kitchen to
the dining area and returning of dishes to the kitchen. It
was also considered to be of utility in the episodes where
“David” could use it while engaging in his hobby, for
example, to move models and tools from storage to a
work surface in a different room.
The term Fetch and Carry comes from H€
uttenrauch
and Eklundh (2002), who in their case study describe
how a user with partial mobility impairment uses a
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LONG-TERM HUMAN–ROBOT INTERACTION
269
mobile robot as a platform for transporting objects that
this person would otherwise be unable to move without
assistance from another person. This particular task is
interesting due to both the utility of the task and the
human–robot interaction issues that it highlights.
The Fetch and Carry capability of robots can be of use
to a wide variety of users because there are many reasons
why they may need assistance for transporting objects,
ranging from fall injuries to neurodegenerative conditions
like Parkinson’s (Kamsma et al. 1995; Walker and Howland 1991). It is also an interesting task from a human–
robot interaction perspective, as it is unique to the physical nature of robots and involves both human and robot
interactants negotiating and moving in a shared physical
space. As long as the robot is capable of moving between
two or more points and is fitted with a suitable container
for the transport of objects, a robust and stable realization
of this task is well within the current state of the art. For
a product prototype implementation for this task, see the
Danish Technological Institute (DTI) robot-butler
“James” (Danish Technological Institute 2012).
The experimental instantiation of the Fetch and Carry
task involved the participants moving 100 plastic balls
from a net on the kitchen bench to the living room table
using only one hand. This was a constraint that was easily implemented while being challenging to the participants. While the balls were very light, requiring little
physical strength, they were quite unwieldy in numbers
larger than four or five, so required several trips back and
forth to transport them all.
Assistance as envisaged with the Cognitive Prosthetic
and Fetch and Carry tasks can be used in response to
changed circumstances, such as recovery from illness and
accidents, as well as rehabilitation after strokes, where
the prospective user will have to learn new skills to aid in
daily living, or gradually recover mastery of old skills.
For the experimental instantiation of both these tasks,
we decided to choose tasks that, while not strenuous,
would present a challenge to the participants, and in
which the use of a robot would have a clear impact on
the task. In addition, it was hoped that the experimental
constraints would add novelty to the task, allowing us to
see the impact of changes in participant task mastery.
Fetch and Carry along the Physical Dimension, and Cognitive Prosthetic along the Mental Dimension). It was
also of interest to see whether these tasks changed over
time (i.e., whether practice changed the nature of the
tasks in terms of experienced workload).
RESEARCH QUESTIONS
Apparatus
Differentiation of Tasks on the NASA TLX
Two robots were used in this study. The first was the UH
Sunflower robot, which uses a Pioneer base (commercially available from MobileRobots) but with significant
modifications (See Figure 3). The main mode of direct
interaction with this robot is its touch-screen (Figure 4),
which can be used to both display information to the user
and issue commands to the robot. Sunflower also has an
extending tray that can be used to carry light objects.
The first research question was whether or not we could
differentiate between the tasks using their NASA Task
Load Index (TLX), a measure for different types of workload that is described in more detail in the methodology
section. It was expected that the two tasks would load
more strongly on their “primary” dimensions (namely,
Research Question 1:
(a) How did the two tasks differ from each other in terms of
experienced workload at the initial presentation?
(b) How did the experience of the tasks change over time?
Impact of the Robot
We were also interested in how the use of the robot
would alter the perceived workload of the two tasks, and
how this impact changed over time. While we expected
the use of the robot to impact the different tasks along
their primary dimensions by reducing participants’ workload in the initial interactions with the robot as an aid, we
were also interested in how the robot impacted the workload on these tasks along the other dimensions.
Research Question 2:
(a) How did the robot impact the experienced workload on
the tasks along the different dimensions of the NASA
TLX?
(b) How did the impact of the robot change over time?
The Experience of the Task and the Robot
Our final interest was in how participants reasoned about
the tasks, and how they described the tasks in terms of
what contributed to their workload and their experience
of the robot’s assistance.
Research Question 3:
(a) How did the participants reason about the tasks? Did
they see them as “natural” and relevant to their own
everyday experience?
(b) How did participants describe the role of the robot in the
task? What where the benefits of its use, and what were
the drawbacks?
METHODOLOGY
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D. S. SYRDAL ET AL.
FIG. 3. The Sunflower robot used in this study. The robot was built at the University of Hertfordshire, significantly extending a
basic Pioneer Platform.
The Sunflower robot is similar in shape and interaction
capabilities to other robots intended for domestic use
(e.g., Coradeschi et al. 2013; Lammer et al. 2014; Koay
et al. 2014). The second robot used in the study was a
SONY AIBO.1
In addition, laptop PCs were set up for Skype calls.
The apparatus for the Fetch and Carry task consisted
of the previously mentioned 100 play balls. The apparatus for the Cognitive Prosthetic task was comprised
of the generic medicine tray and scrabble tiles as
shown in Figure 5. Both of these are widely available
commercially.
Experimental Setup
Participants were asked to visit the robot house once a
week for a period of 10 weeks, in order to study how participants’ views of, and interactions with, the robots
changed over time. See Table 1 for an overview of the
sessions that the participants took part in. References
made in this article to a specific week are based on
Table 1. While the participants would only do the controlled, task-based prototyping experiment in weeks 1, 2,
5, and 8, it is important to note that in these other sessions
they interacted with the robot, using its touch-screen
LONG-TERM HUMAN–ROBOT INTERACTION
271
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FIG. 4. Interacting with the touch-screen interface on the
Sunflower robot.
interface and moving in the same space as the robot, thus
familiarizing themselves with the robot and its use
between the constrained task-based experiments. Each
session took about 1 hour, including debriefing.
Procedure
Introduction. The introduction session introduced the
UH Robot House and the robots to the participants. The participants were instructed in the use of the Sunflower robot
and touch-screen, as well as how this robot responded to
scheduled and sensor events. The participants were given a
tour of the living areas where they would interact with the
robot, and were shown the kitchen cupboards and fridge
shelves that would be “theirs.” In addition, they were introduced to the AIBO robot and its use in remote human–
human interaction scenarios. Throughout this tour, participants were encouraged to think of these areas as their home
and to put themselves in the mind set of someone living in
the house. This was intended to begin the process of framing
the narrative (Dindler and Iversen 2007) of the open-ended
scenarios. It was also intended as a session in which the participants could make themselves as comfortable in the house
as possible. The session ended with the baseline experiment.
Open-ended scenarios. As mentioned earlier, there
were two open-ended scenarios that were presented twice
to the participants. At the beginning of each open-ended
scenario session, the participants were given a narrative
framing of the context of the scenario that they were taking part in. They were told the time of day, and also what
had transpired immediately before the beginning of the
scenario. Scenario A began in the morning and the participants were told the following:
Imagine that you have now woken up. In the introductory session
you gave us some preferences for what you would like to do in the
early morning. The robot has stored these preferences and will try to
help you do them. When you are ready, you will come out of the
bedroom and sit down on the sofa. The robot will then approach you.
FIG. 5. Medicine dispenser and Scrabble tiles used in the Cognitive Prosthetic task as part of the controlled experiments.
Scenario B began in the afternoon:
Imagine that it is afternoon and you have just returned home
and have just sat down on the sofa. You have planned to watch
some TV. In the introductory session, you gave us some preferences as to what TV programs you like to watch and also what sorts
of snacks and drinks that you prefer to eat. The robot has stored
these preferences. It will also respond to events such as phone calls
and doorbells. When you are ready to begin, sit down on the sofa
and the robot will approach you.
After this briefing, the scenarios ran as outlined previously. Participants were asked to fill in questionnaires
after the scenario was completed.
Constrained experiments. There were two sets of
conditions for the experiment:
1. Task:
a. Fetch and Carry.
b. Cognitive Prosthetic.
2. Robot:
a. Human-Only.
b. Robot and Human.
In the baseline experiment in Week 1, participants
undertook both task conditions in the human-only condition. The presentation order of the two tasks was counterbalanced in order to account for a presentation effect. In
weeks 2, 5 and 8, participants did both task conditions for
both of the robot conditions for a total of 4 trials in these
weeks. The presentation order was within each week, for
both Task and Robot conditions. Participants were given
a questionnaire to respond to after each run of a task.
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D. S. SYRDAL ET AL.
TABLE 3
Open-ended questions
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Robot Use
The use of the robot was adapted to each task: For the
Fetch and Carry task, participants were allowed to use
the extendible tray of the robot as an additional platform
to transport the plastic balls to the living room table. The
participants could instruct the robot to move between
the locations using the touch-screen interface. For the
Cognitive Prosthetic task, the participants could access
the list through the touch-screen interface. The participants could only access one quarter of the list at any
given time, and could only choose which portion of the
list to access while in the kitchen. This meant that in
order to access the whole list, they would have to make
several journeys between the living room and the kitchen
over the course of the trial.
Instructions. Before each task, participants were
shown the apparatus involved in each task, and had
the task explained to them. For the robot condition, participants were shown how to use the robot, and how to
operate the touch-screen interface relevant for that particular task. Participants were asked to try to complete
the task as quickly as possible. They were told that their
performance was not being assessed, and that if the task
took longer than 10 minutes to complete, the experimenters would stop the experiment.
Q1. What was the most difficult part of doing the task?
Q2. What would have made the task easier?
Q3. What were the benefits of doing the task with the robot?
Q4. What were the drawbacks of doing the task with the robot?
been used across a wide variety of domains and tasks
(Hart 2006). It was chosen over the more focused
Human–Robot Interaction Workload Measurement
(HRI-WM) (Yagoda 2010) because the main focus of
our study was on the participants’ experience of the tasks
themselves, rather than an assessment of how they interacted with the robot. The NASA TLX measures workload along six dimensions, shown in Table 2.
Ad Hoc Questions
In addition to the NASA TLX, participants were asked
open-ended questions, inviting them to describe their
experiences of the tasks themselves, as well as the role of
the robot within them. These questions are shown in
Table 3.
Measures: NASA Task Load Index
Participants
We used the NASA Task Load Index (TLX) as the primary measure for the evaluation of the constrained tasks.
The NASA TLX is a questionnaire-based means of measuring workload for specific tasks along several different
dimensions. It is particularly intended for examining
human–machine interactions (Hart and Staveland 1988).
As it is a posttask measure, administering it to a participant would not affect task performance in the manner
that a concurrent measure such as a think-aloud protocol
might (Russo et al. 1989). Despite it being a subjective,
posttask measure, studies have shown it to be a reliable
and valid tool for examining task difficulty and performance (Rubio et al. 2004). Since its conception, it has
Twelve participants took part in the study, recruited
through advertisements on the University of Hertfordshire Intranet, mailing lists, and social networks. There
were eight males and four females in the sample. The
mean age was 32 years and the median age was 26 years,
and the age range was 18–64 years. The use of human
participants had been approved by the University of
Hertfordshire Ethics Committee under protocol number
1112/39.
RESULTS
The results for the constrained tasks with respect to the
original research questions were as follows.
TABLE 2
Dimensions of the NASA Task Load Index
Dimension
Mental
Physical
Temporal
Performance
Effort
Frustration
Workload in terms of . . .
. . . reasoning remembering, planning, thinking
. . . strength and endurance, dexterity
. . . pace, time pressure, speed
. . . success and satisfaction
. . . effort needed to accomplish performance
. . . annoyance, frustration, stress
Research Question 1: Characteristics of the Task
Baseline values. The differences between the two
tasks were examined using a series of t-tests (Table 4
and Figure 6). As could be expected, the TLX significantly differentiates between the two tasks in terms of
the physical and mental dimensions. The most salient differences between the two can be seen along the Physical
Dimension (which contributes significantly more to the
workload of the Fetch and Carry task) and the Mental
273
LONG-TERM HUMAN–ROBOT INTERACTION
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TABLE 4
TLX baseline scores for tasks
Dimension
Fetch and Carry
mean (SE)
Cognitive Prosthetic
mean (SE)
Mental
Physical
Temporal
Performance
Effort
Frustration
0.50 (.14)
2.46 (.62)
1.89 (.51)
0.83 (.33)
1.15 (.30)
1.51 (.47)
2.75 (.58)
0.70 (.25)
1.95 (.46)
0.63 (.26)
1.40 (.30)
0.58 (.18)
Dimension (which contributes significantly more to the
workload of the Cognitive Prosthetic task). There is a
trend approaching significance for the Frustration
Dimension, which suggests that it contributes more to
the workload of the Fetch and Carry task.
Long-term change. Change across the 8 weeks for the
Fetch and Carry task is described in Table 5 and Figure 7.
They suggest that the only significant change for this task
was along the Effort Dimension, which contributed more
to the workload in this task in later weeks than the first
week. Change across the 8 weeks for the Cognitive Prosthetic task is described in Table 6 and Figure 8, suggesting that overall there were no significant changes for this
task in terms of what dimensions contributed to the workload on this task. However, a trend approaching significance indicates that the Temporal Dimension contributed
less to the workload of this task in later weeks. Also,
while the descriptive statistics of Table 6 suggest that
there was an equally substantial mean change in the Mental Dimension, the variance between participants’ individual scores stopped this change from being significant for
this sample.
Mean
difference
¡2.25
1.75
¡0.07
0.19
¡0.25
0.94
95% CI
¡3.44 to 1.07
0.32 to 3.19
¡0.99 to 0.86
¡0.72 to 0.86
¡0.72 to 1.10
¡0.20 to 2.07
t(df)
p
4.20 (11)
2.69 (11)
¡0.16 (11)
0.46 (11)
¡0.62 (11)
1.82 (11)
**.01
**.02
.88
.65
.55
.10
Research Question 2: Robot Impact
Fetch and Carry. The overall impact of the robot can
be found in Table 7 and Figure 9. There were significant
main effects for the role of the Robot along the Physical,
Temporal, Performance, and Effort dimensions. However, all of these main effects, with the exception of Performance, were mediated by interaction effects between
the role of the robot and the long-term effects, so we consider these interaction effects in the text as well. For Performance, there was a main effect for robot assistance.
This effect suggests that performance was experienced as
worse with the robot than if the participant acted on his
or her own. This effect was very pronounced in week 2
but decreased with time. For the Physical dimension,
there was a significant interaction effect between time
and assistance. The relationship suggested by the
descriptive statistics in Table 7 and Figure 9b is that the
participants found that the robot reduced the workload
overall but this effect decreased after week 2. For the
Temporal Dimension, there was a significant main effect
described in Figure 9c, where participants found that the
robot overall increased the Temporal aspects of workload. The interaction effect approaching significance,
FIG. 6. TLX baseline scores for tasks.
274
D. S. SYRDAL ET AL.
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TABLE 5
Long-term change for Fetch and Carry task
Dimension
Week 1
Week 2
Week 5
Week 8
F(3, 8)
p
h2
Mental
Physical
Temporal
Performance
Effort
Frustration
0.50 (.14)
2.46 (.62)
1.89 (.51)
0.83 (.33)
1.15 (.30)
1.51 (.47)
0.19 (.06)
3.01 (.46)
1.30 (.29)
0.58 (.19)
2.50 (.37)
0.95 (.25)
0.20 (.06
3.09 (.58)
2.25 (.44)
0.83 (.34)
1.84 (.42)
0.88 (.20)
0.17 (.14)
2.70 (.56)
1.95 (.50)
0.34 (.05)
2.45 (.40)
1.02 (.34)
0.99
2.44
1.20
2.15
5.48
1.52
.45
.14
.37
.17
*.02
.28
.27
.48
.31
.45
.67
.36
however, suggests that this effect decreased over time.
The robot’s impact on the Effort Dimension was quite
small in weeks 2 and 5. However, by week 8, the assistance of the robot reduced the workload along this
dimension (see Figure 9e).
thus making the task both more frustrating and timecritical.
Cognitive Prosthetic. The overall impact for the
robot on the Cognitive Prosthetic Task is shown in
Table 8 and Figure 10. The impact of robot assistance
was primarily along the Mental, Performance, and Effort
dimensions. There were no interaction effects.
Participants viewed the robot as reducing workload
along the Mental Dimension. This was consistent across
the 3 weeks. On the other hand, the descriptive statistics
in Table 8 suggest that participants saw the robot as adding significantly to the workload along the Performance
Dimension (i.e., making it harder to succeed on the task).
This effect is less pronounced in the last week. The other
significant impact was along the Effort Dimension. The
descriptive statistics in Table 8 suggest that participants
found they needed to exert less effort when aided by the
robot. There were also two nonsignificant trends for the
Temporal and Frustration dimensions. These trends suggested that the participants saw the use of the robot as
contributing to more workload in these two dimensions,
The analysis of participant responses to qualitative questions (see Table 3) was conducted in two main stages. In
the first stage, one of the researchers examined the openended qualitative responses from the questionnaires and
categorizsed them into primary themes and subthemes
for each task and each week. These themes were then
examined across weeks for each of the tasks. This led to
the collection of themes identified in the first two columns in Tables 9 and 10. A unified category scheme for
both tasks could not be developed, largely due to the
large qualitative differences between the tasks. After this
categorization, two of the researchers went through the
responses and categorized them as major (C), minor (¡),
and nonexistent (0).
The themes that were the most prevalent in the
responses were categorized as major. Minor themes were
those less prevalent but still reported by a small group of
participants. Themes that did not appear in the responses
for a particular week were categorized as nonexistent.
Research Question 3: The Experience of the Task and
the Robot’s Role
FIG. 7. Long-term change for Fetch and Carry task.
275
LONG-TERM HUMAN–ROBOT INTERACTION
TABLE 6
Long-term change for Cognitive Prosthetic task
Dimension
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Mental
Physical
Temporal
Performance
Effort
Frustration
Week 1
Week 2
Week 5
Week 8
2.75 (.58)
0.70 (.25)
1.95 (.46)
0.63 (.26)
1.40 (.30)
0.58 (.18)
1.97 (.48)
0.72 (.30)
1.78 (.44)
0.93 (.28)
1.32 (.31)
1.08 (.42)
2.21 (.51)
0.63 (.26)
1.04 (.30)
0.76 (.22)
1.25 (.27)
0.60 (.21)
1.81 (.38)
0.60 (.18)
1.22 (.43)
0.68 (.32)
1.22 (.28)
.32 (.10)
The final categorization and assignment of the themes
was done by the researchers, after having compared their
coding of responses, discussed discrepancies, and
reached a consensus.
Fetch and Carry. The themes emerging from the participants’ responses are described in detail next and summarized in Table 9:
Week 1. For the Fetch and Carry task, the two primary
themes emerging from Q1 (What made the task difficult?) were the physical difficulty of handling the balls
and the constraint of using only one hand when performing the task. They were also evident in the responses to
Q2 (What would have made the task easier?) where the
possibility of release from this constraint was the predominant theme.
Week 2. Week 2 saw the introduction of the robot, and
Q1 and Q2 were asked for both the human-only and the
robot–human condition. For the human-only condition,
the theme of the constraint continued among some of the
participants. Participants would also contrast the humanonly condition with the use of the robot when answering
questions related to both conditions. When contrasting
the conditions, participants highlighted the practical benefit of being able to perform the tasks in fewer trips.
However, the second most prevalent theme in the
F(3, 8)
1.29
0.23
3.87
1.63
1.23
2.31
p
h2
.34
.87
*.06
.26
.36
.15
.33
.08
.59
.38
.32
.46
participants’ statements was the slow speed of the robot.
The sample as a whole agreed that the speed of the robot
was problematic from a task perspective, with participants having to change their speed of performing the
task to accommodate the robot. This was achieved either
by walking (more slowly) with the robot to the living
room and back, or by waiting at the appropriate place to
load or unload to the robot. In response to Q2 for the
robot condition, the participants overwhelmingly suggested increasing the speed of the robot and/or the size
of the tray. They also suggested that an ability of the
robot to manipulate objects by loading itself would be
helpful. In addition to purely task-related comparisons, a
small group of participants highlighted interactional
aspects of doing the task with the robot: that the robot
provided company or that the task was more enjoyable
when using the robot.
Week 5. Week 5 saw a continuation of the same
themes as in week 2. New themes also emerged related
to how participants rated their own performance. Some
participants identified changes in their own behavior
between conditions. They referred to a type of social
loafing (Latane et al. 1979) that occurred when they did
the task with the robot, and that they put more effort in
when they were doing the task by themselves. Other
FIG. 8. Long-term change for Fetch and Carry task.
276
D. S. SYRDAL ET AL.
TABLE 7
Robot impact on Fetch and Carry
Dimension
Mental
Physical
Temporal
Performance
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Effort
Frustration
Human
Robot
Human
Robot
Human
Robot
Human
Robot
Human
Robot
Human
Robot
Week 2
Week 5
Week 8
0.20 (0.20)
0.95 (1.54)
3.26 (1.41)
0.26 (0.54)
1.39 (1.01)
6.10 (5.84)
0.61 (0.67)
2.01 (3.11)
2.72 (1.03)
2.28 (2.50)
1.03 (0.85)
0.21 (0.19)
0.20 (0.20)
0.27 (0.20)
3.09 (1.91)
1.83 (1.29)
2.25 (1.47)
2.25 (1.68)
0.83 (1.13)
1.46 (1.78)
1.84 (1.40)
1.61 (1.00)
0.88 (0.66)
0.65 (0.96)
0.17 (0.25)
0.20 (0.20)
2.70 (1.86)
1.70 (1.07)
1.95 (1.67)
1.67 (1.47)
0.33 (0.16)
0.56 (0.89)
2.46 (1.33)
1.22 (0.96)
1.02 (1.14)
1.05 (0.85)
ME
F
(3, 8)
ME
p
ME
h2
In F
(3,8)
In
p
In
h2
3.83
.08
.29
1.24
.33
.22
16.16
.01*
.62
13.17
.01*
.75
7.65
.04*
.35
4.00
.05*
.47
7.65
.02
.43
1.41
.29
.24
4.61
.05*
.32
5.64
.03*
.56
1.83
.21
.16
2.28
.16
.34
FIG. 9. Robot impact on Fetch and Carry in terms of experienced workload.
277
LONG-TERM HUMAN–ROBOT INTERACTION
TABLE 8
Robot impact on Cognitive Prosthetic
Dimension
Mental
Physical
Temporal
Performance
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Effort
Frustration
Human
Robot
Human
Robot
Human
Robot
Human
Robot
Human
Robot
Human
Robot
Week 2
Week 5
Week 8
2.13 (1.63)
0.76 (0.90)
0.77 (1.08)
0.36 (0.38)
1.93 (1.53)
2.38 (1.64)
0.99 (0.99)
2.19 (1.14)
1.41 (1.05)
0.94 (0.77)
1.18 (1.47)
1.90 (2.16)
2.21 (1.71)
0.73 (0.98)
0.63 (0.85)
0.49 (0.65)
1.04 (0.99)
1.92 (1.63)
0.76 (0.72)
1.14 (1.51)
1.25 (0.90)
0.72 (0.87)
0.60 (0.69)
1.10 (1.47)
1.81 (1.26)
0.88 (1.72)
0.60 (0.61)
0.83 (0.75)
1.22 (1.41)
1.04 (0.99)
0.68 (1.05)
0.81 (1.06)
1.22 (0.94)
0.95 (0.70)
0.32 (0.32)
1.34 (1.33)
ME
F
(3, 8)
ME
p
ME
h2
In
F
(3, 8)
In
p
In
h2
16.24
.01*
.62
0.42
.67
.08
0.34
.58
.01
2.80
.11
.38
3.63
.09
.27
0.48
.64
.10
5.90
.04*
.37
1.23
.34
.21
4.79
.05*
.32
0.23
.8
.05
3.21
.10
.23
0.56
.59
.11
FIG. 10. Robot impact on Cognitive Prosthetic in terms of experienced workload.
278
D. S. SYRDAL ET AL.
TABLE 9
Themes for the Fetch and Carry task
Primary theme
Imposed constraint
Use of the robot
Speed of the robot
Changing capabilities
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Interactional aspects
Subtheme
Week 1
Week 2
Week 5
Week 8
Using one hand
Benefit from the tray
Mutual adaptation
Interface
Having to wait
Walking with the robot
Changing speed
Changing tray
Object manipulation
Robot as partner
Enjoyment
Social loafing
C
0
0
0
0
0
0
0
0
0
0
0
C
C
0
0
C
C
C
C
C
C
C
0
C
C
–
C
C
0
C
C
0
C
C
C
–
C
C
C
–
0
C
C
–
C
C
C
Note. C Theme present; – theme present to a lesser degree than in the other weeks; 0 theme not present.
participants highlighted mutual adaptation. They
reported that they were getting better at coordinating
their own and the robot’s roles in the task, reducing waiting, and making the use of the robot more efficient. The
most common strategy was to perform the task in an
asynchronous manner, only loading and unloading the
robot at convenient times instead of synchronizing each
trip. However, for the sample as a whole, the theme of
having to wait for the robot was still prevalent. In addition, this week saw statements regarding the touchscreen interface for this task. There were no statements
regarding object manipulation capabilities in this week.
In addition, participants continued to reference the social
aspects of doing the task with the robot.
Week 8. Week 8 was very similar in terms of themes
to Week 5. The main difference was one of prevalence.
The theme of mutual adaptation continued and was more
widespread, while the theme of having to wait for the
robot was much less prevalent this week.
Cognitive Prosthetic. The themes arising from the
participants’ responses for this dimension are described
below and summarized in Table 10.
Week 1. In week 1, two main themes arose in participant responses to Q1. The first was the difficulty of
TABLE 10
Themes for the Cognitive Prosthetic task
Primary theme
Imposed constraints
Performing the task
Nonrobotic tool
Robot benefits
Robot drawbacks
Subtheme
Week 1
Week 2
Week 5
Week 8
Separation of list and dispenser
Robot positioning
Random order of tiles and position in list
Difficulty in trying to remember
Physically manipulating the tiles
Use of strategy
Pen and paper
Tray
Easy
Infallible/no pressure
Subversion
Slow
Flexibility
Interface issues
Control
C
0
–
C
0
–
C
C
0
0
0
0
0
0
0
–
–
C
–
0
–
–
C
C
C
0
C
C
–
C
–
C
–
–
–
C
–
–
C
C
C
C
C
C
C
–
C
–
–
C
C
–
–
–
C
C
C
C
C
C
Note. C Theme present; – theme present to a lesser degree than in the other weeks; 0 theme not present.
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LONG-TERM HUMAN–ROBOT INTERACTION
having to remember the position of the tiles while walking from the kitchen to the living room. The second was
the attempt at developing a strategy for solving the task
without having to rely on memory alone. Responses to
Q2 did, as for the Fetch and Carry task, focus on the constraints of the task—in particular, the placement of the
list of tile positions in a separate location from the medicine dispenser, and the list of tiles not being in any discernible order. A small group of participants managed to
develop a strategy for doing this task more efficiently,
which consisted of arranging tiles spatially in one’s palm
in the same manner that they were to be arranged in the
medicine dispenser and then transporting them over and
inserting them into the dispenser in the same order. The
final theme was an expressed desire for tools to aid in the
task. There were two categories of tools: reminder tools,
such as a pencil and paper to jot down the appropriate
tiles and their positions, and tools to make the strategy
described earlier more efficient. An example of the latter
would be a large tray to arrange and carry all the tiles on
at once.
Week 2. In the human-only condition, the adoption of
the strategy just described became more prevalent as
fewer participants relied on memory alone to perform the
task. This change was also reflected in the suggestions for
tools to be used, where items that would aid in the use of
this strategy were suggested to a larger extent than in the
previous week. When discussing the role of the robot, participants raised several issues. They considered the robotassisted solution of the task to be easier, as there was no
need to either remember anything or adopt a strategy. Participants in particular referred to the infallibility of the
robot’s memory and how this made them feel less under
pressure to perform the task correctly.
However, participants referenced the interaction with
the robot in itself as a source of difficulty for the task as
well. The robot was also described as slow and lacking
in flexibility. The relinquishing of control to the robot
was also referenced when discussing the procedure used
to access the information on the robot.
Week 5. The results in week 5 followed many of the
same themes as week 2. There was a continued increase
in the use of the strategy outlined in week 1. By this
week the majority of participants used this strategy for
the human-only condition. References to interface issues
were more prevalent in this week’s responses, as were
references to the physical aspect of the task, such as
manipulating and putting the tiles in the dispenser. This
week also saw a new theme of subversion emerging.
Two of the participants described how they used the
robot the way they wanted to, instead of how they felt
they were being expected to. They arranged the tiles spatially on the tray of the robot in the kitchen and then used
it to transport them in the correct arrangement to the
279
dispenser in the living room, thus sidestepping the use of
the robot as a Cognitive Prosthetic.
Week 8. Week 8 results were similar to those in
week 5. Statements related to the physical carrying out
of the task were more prevalent this week than on any
other week. The majority of participants stated that the
task had become easier for them to do. However, many
still referenced the benefits of the robot, in particular its
infallibility.
DISCUSSION
Research Question 1—Differences Between
the Tasks
We were able to differentiate between the tasks in terms
of their NASA TLX profile. Initially, the two tasks were
significantly different from each other only along their
primary dimension, with a trend for the Fetch and Carry
task loading more on the Frustration Dimension. In terms
of long-term change, however, the picture was slightly
different. While neither of the two tasks changed on the
Frustration Dimension, they did change along other
dimensions. The Fetch and Carry task changed in terms
of Effort, and loaded higher on this dimension in the later
weeks. The Cognitive Prosthetic task changed along the
Temporal Dimension, and time pressure was considered
less important in weeks 5 and 8. This suggests that the
use of the NASA TLX for HRI tasks in domestic environments was a valid and meaningful approach.
Research Question 2—Impact of the Robot
The robot changed the participants’ experience of the
two tasks differently, both in its initial use as well as over
time. For the Fetch and Carry task, the robot initially
impacted the participants’ ratings of the physical and
temporal dimensions. In week 1, while the robot-assisted
task was considered less physically strenuous, the participants found the time taken to be burdensome. The trend
for the physical dimension continued in the subsequent
weeks. However, the impact of the robot on the temporal
dimension diminished, suggesting that participants found
it easier to use the robot to complete the tasks in weeks 5
and 8. Furthermore, participants found that the use of
robot required less effort in the last week, suggesting that
there was a learning effect, and that participants were
able to use the robot more efficiently as time progressed.
This was also seen in the manner that the participants
reported they used the robot and as well as in their
observed usage. In week 2, participants would load themselves and the robot and then follow the robot to the living to unload it. They would then return to the kitchen
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280
D. S. SYRDAL ET AL.
with the robot. In subsequent weeks, participants would
be more likely to not wait for the robot, but rather move
around the robot and only load/unload it if they happened
to be in the same space as it. This approach employed the
robot more efficiently as a supplement to their own capabilities. For the cognitive prosthetic task, the impact of
the robot was less clear-cut. Participants rated doing the
task with the robot as requiring less mental workload,
and this effect persisted throughout the trials. In addition,
participants felt that doing the task with the robot
required less effort. Despite this, participants rated the
use of the robot as requiring more workload in order to
perform the task successfully. There was a trend suggesting that for weeks 2 and 5 the use of the robot was seen
as more time-consuming; it was also seen as more frustrating across all the trials.
This suggests that despite the experienced benefit of
using the robot in this task, there were still associated
problems that made it more time-consuming and
frustrating.
Research Question 3—The Experience of the Task
The descriptive analysis of the open-ended questions
allowed for a deeper and more thorough perspective about
the tasks and how they were experienced by the users.
When discussing the initial tasks, participants referenced the constraints imposed on them. Many of their
suggestions for making the task easier involved the
removal of these constraints. In the cognitive prosthetic
task, the participants also considered the means through
which they could access the information on the robot as
one of the constraints.
In addition, the results from the TLX along this task
were mirrored in the way that participants reasoned about
the task. Participants described the robot as slow and
inflexible and expressed a need to change the way that
the robot was used in the task, either by changing how
information was presented or by changing the usage of
the robot. This was a reflection not just on their experience of the robot, but also how their increased mastery of
the task made them consider the role of the robot differently. This even led to two of the participants using the
robot in a manner unintended by the experimenters.
They asserted control by subverting its use and using the
Fetch and Carry functionalities to aid in the Cognitive
Prosthetic task. For the remainder of the sample, however, there seemed to be a tacit understanding of a tradeoff between the lack of human error in this task and the
lack of control. In the Fetch and Carry task, however,
despite similar descriptors of the robot being used in
terms of it slowing down the task, participants adapted
their use of the robot. This allowed the participants to
work around these shortcomings and receive beneficial
assistance from the robot. The changes that the participants mainly wanted to implement in terms of how they
interacted with the robot were mainly quantitative
changes: giving it more space to carry things and letting
it move more quickly, in contrast to the changes in the
quality of assistance that were suggested in the Cognitive
Prosthetic task. It also emerged that, unlike in the Cognitive Prosthetic task, users referenced the robot as a partner and companion in the Fetch and Carry task. This may
reflect the open-ended nature of this interaction, and the
opportunity for a natural synchronization of behavior to
occur gradually. Stienstra and Marti (2012) suggest this
is a key factor in developing feelings of sociality and
empathy in an HRI situation.
Ecological Validity
The narrative framing of the interactions within the
Robot House environment enabled participants to evaluate their interactions in a more relevant and applicable
manner than what would have been possible in a traditional laboratory study. Despite the fact that the constrained tasks were part of an experimental study where
the participants’ interaction with the robot was tightly
controlled, there are several factors that support the ecological validity of this study. These tasks were based on
the needs of the user personas, and expected interactions
arising from these needs. The parallels between observed
behaviors and similar interactions with technologies in
everyday settings were also encouraging. In the Fetch
and Carry task, the process the participants went through
when completing the tasks with the robot was quite similar to that of the user in the H€uttenrauch and Eklundh
(2002) study. In both cases, the users started off by coordinating their behavior closely with the robot, for example, walking with the robot, and synchronizing their own
behavior with that of the robot. They then progressed to
using the robot in a more asynchronous manner, with
less constant control of the robot. These similarities in
interactional outcomes support the notion that many of
the qualities of a real-world usage of a final stage prototype were successfully translated into the experimental
setup. For the Cognitive Prosthetic task, the manner in
which the participants described the role of the robot in
the task had elements that map well onto how people perceive such technologies in real-world settings. The issues
of autonomy and control come up in both theoretical and
practical discussions of the use of robotic technologies
(Anderson and Anderson 2008; Sharkey and Sharkey
2012). In particular, the resolution of control issues by
subverting assistive technologies has also been reported
in real-world settings (Loe 2010), and an analogous
LONG-TERM HUMAN–ROBOT INTERACTION
process took place within the experiments. This suggests
that for the cognitive prosthetic tasks, many of the salient
aspects of using such technologies could be effectively
conveyed through this constrained method.
Downloaded by [University of Hertfordshire] at 03:35 02 June 2015
Implications
The findings highlight the need for a user-centered
approach to assistive technologies intended for domestic
use. The results from the constrained task experiments
strongly stress the need for such assistance to allow for
personalization and for the robot assistance to be gradually
scaled in order to account for changes in task mastery in
the user and for coping strategies that the user may adopt.
The TLX scores for the Cognitive Prosthetic tasks suggest
that total experienced workload may increase where such
scaling and alteration of assistance do not occur, due to
frustration and disruption to learned coping strategies,
despite the robot’s assistance being still considered useful.
In addition, the open-ended responses to this task suggested that participants came to regard the robot’s assistance as hindering their preferred solution to the task. The
scores for the Fetch and Carry task, on the other hand, represent a scenario where the roles of both the robot and the
participants were less strongly defined. This left a lot of
room for mutual adaptation, which in turn led to a more
successful interaction in terms of the TLX scores, and also
in terms of the participants’ reasoning about the task and
the role of the robot. This suggests that even in constrained
tasks, such as the ones presented here, there is a hedonic
dimension to interactions that has a role equal to their
purely task- and workload-related aspects. This hedonic
quality may be impacted by anthropomorphic interaction
capabilities, and an interesting future strand of research
into task-related domestic human–robot interaction would
be to investigate the role of such capabilities in how users
respond to performing tasks with robots.
CONCLUSIONS
The work presented in this article has shown the validity of
interaction prototyping, in terms of both a high-level narrative approach in which the participants is involved in the
playing of the role of a user of a more “mature” version of
the technology being prototyped, and that of separating the
task-aspect of such interaction. This two-pronged approach
to interactions with future and emerging technologies for
the purposes of early prototyping is a valid tool for gaining
insight into how such interactions may be experienced by
the intended users. The findings in this study have allowed
us to replicate findings of real-world studies in terms of
how participants reason about their potential adoption of
such technologies, as well as to quantify the impact of
281
assistance in such tasks using the NASA TLX and to highlight issues relevant for the UH Robot House Scenario and
human–robot interaction in general.
The work described in this article showed how to successfully integrate constrained tasks (as part of controlled
experiments) with more “natural,” open-ended scenarios
as part of a long-term study into home companion robots
operating in domestic environments. We pointed out
experimental and methodological challenges and how
they have been addressed in this study. The constrained
tasks were based on commercially available tools and as
such could potentially be used and replicated by other
researchers. Being able to share, replicate, and build
upon each others’ results remains one of the big challenges in human–robot interaction, which otherwise
remains in danger of staying a widely fragmented field
with different research groups using different robotic
platforms, scenarios, and methodological approaches
(Dautenhahn 2007). We therefore hope that, in addition
to presenting concrete results from a long-term human–
robot interaction study, this article has also raised awareness of the main challenges as well as opportunities in
the design of interaction technology that supports longterm human–robot interaction.
NOTE
1. Previous studies examining the application of biologically inspired expressive behaviors to Sunflower had shown
that participants found the robot’s non-anthropomorphic communicative behavior very effective in terms of conveying the
robot’s intention (Koay et al., 2013).
ACKNOWLEDGEMENTS
We would like to thank our colleagues Michael L. Walters
and Joe Saunders for helpful comments, and Fotios Papadopolous for his help with the AIBO robot.
FUNDING
The research leading to these results has received funding
from the European Union’s Seventh Framework Programme
(FP7/2007-2013) under grant agreement 287624, the
ACCOMPANY project, and grant agreement 215554, the
LIREC (LIving with Robots and intEractive Companions)
project.
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