A Case in Point: Social Facilitation
\label{sec:mere-presence}
Context: Studying the Mere Presence Effect in Social Facilitation
Background and Related Theories
In 1898, Norman Triplett \cite{Triplett1898} observed that cyclists pedal faster
in presence of rivals than when they are alone. He studied this effect on
children by using a fishing reel that they need to turn as quickly as possible
and found the same effect, although a later analysis of his work by
Stroebe \cite{Stroebe2012} showed that there was no significant difference in
his findings. This effect has later been termed as ‘social facilitation’ by
Allport \cite{Allport1924} to describe the increase in response due to the
presence of others who are performing the same task. Social facilitation occurs by two
types of condition: ‘co-action effects’ like Triplett’s examples, and ‘audience
effects’, in which only the mere presence of an observer effects the performance
of a person performing the task. In order to explain the audience effects,
Zajonc \cite{Zajonc1965} proposed the drive theory, which states that the
audience enhances the exhibition of dominant responses in a person. In the case
of a well-mastered task (‘simple task’), the performance is facilitated, whereas,
for the tasks that are new or require learning (‘complex tasks’), the performance
is inhibited.
Many other theories underpin social facilitation: anticipation of
evaluation \cite{Cottrell1972}, attentional conflict \cite{Sanders1975},
monitoring \cite{Guerin1983}, self-awareness \cite{Duval1972} and
self-presentation \cite{Bond1982}.
Factors
A meta-analysis by Bond and Titus \cite{Bond1983} compares 202 published and 39
unpublished studies on social facilitation. They provide a list of
13 factors that might impact social facilitation (like the participants’ age,
the number of observers, the role of the observers, the
familiarity of the observers, etc.). The meta-study shows that the
performance speed (‘quantity’) is increased for the simple tasks and the
performance accuracy (‘quality’) is decreased for the complex tasks. The
performance quantity is measured by the latency to respond, time it takes to complete a
task and the number of responses per unit time. The performance quality is
measured by the number of errors.
The study also shows that the visibility of the observers to the subjects has a
slightly bigger effect than the non-visibility, although the difference was not
significant. Examples from the literature are use of a one-way
mirror \cite{Ganzer1968, Criddle1971}, use of a video camera \cite{Geen1973,Terry1993}, or a desktop image on a computer screen \cite{Gardner2008}. On the
other hand, Bernard Guerin \cite{Guerin1983} argues in a review that the
majority of studies with social facilitation effects had observers or the
experimenters watching the subject while the task was performed, that is, they
were not busy with other tasks. However, he states that there should be some
uncertainty if the observer will evaluate the subjects, which meant that there
should be evaluation potential which the subject should not know beforehand. He
also draws attention the ceiling and floor effects for the tasks. He states that
the task should be difficult enough so that the measurements can vary between
subjects and conditions.
Tasks
Following Zajonc, the literature on social facilitation distinguish between
‘simple tasks’ and ‘complex tasks’. Examples of simple tasks include
letter cancellation, multiplication, and vowel
cancellation; examples of complex tasks include concept formation, anagrams, digit span, and pursuit rotor tasks.
Tasks such as letter-copying and paired associates can be either simple or complex depending on the task structure. McCaffrey et al. \cite{McCaffrey1996} also presented significance levels of each of these
tasks in the literature. It shows that visual perception and construction tasks
such as letter/word copying \cite{Guerin1989, Terry1993, Gardner2008} and motor
tasks such as physical activities \cite{Strube1981} are good tasks in terms of
significance as simple tasks, and memory or learning tasks such as paired
associates \cite{Cottrell1967, Geen1973, Guerin1983} and visuomotor tasks as in
rotary pursuit performance \cite{Lombardo1975, Miller1979} have higher
significance for social facilitation as complex tasks.
Cheating as a reinforcing factor
Self-presentation theory \cite{Bond1982} also suggests conformity to normative
behaviours to gain approval of another person. For example, in the case of an
embarrassing situation such as cheating, this should prevent the subject from
engaging in the cheating behaviour due to social pressure. There might be
several factors that effect cheating behaviour as examined by several
researchers, such as the importance of the task, risk of being caught,
probability of success \cite{Vitro1972}, belief in free-will \cite{Vohs2008},
knowledge of peer performance \cite{Hill1969}, higher gain of money or grades,
penalty \cite{Nagin2003} or conformity to cheating behaviour in
peers \cite{Fosgaard2013}. In the study by Vohs and Schooler \cite{Vohs2008}, in order to
observe the cheating behaviour, a computer-based mental arithmetic test was
used. The participants were made aware that there is a glitch in the program
which shows the correct answer to the problem but they could close the answer
window by pressing a key after the problem appeared. They were also told that
the experimenter would not know whether they pressed the bar, even though the
number of presses was recorded, but they should try to solve the
problems honestly. Their results revealed that those who were given an essay prior
to the test that stated the lack of free-will cheated more frequently than others.
Social Facilitation In Robotics
The audience effect has been studied in HRI by
Schermerhorn \cite{Schermerhorn2008} and Riether et al. \cite{Riether2012}.
Schermerhorn compared the effect of the robot presence during easy and difficult
arithmetic tasks with alone and robot-presence conditions. A significant two-way
interaction between gender and robot was found, because the male subjects
performed worse during the difficult task when the robot was present. Overall, a
marginally significant effect of robot presence was found. Riether et al. on the
other hand, compared alone, human-presence, and anthropomorphic robot-presence conditions
with four different tasks with easy and complex conditions: anagram solving,
numerical distance, finger tapping and motor reaction task. They observed that
in the anagram solving, numerical distance and finger tapping tasks, there were
significantly larger difference scores than the alone group for both robot and
human conditions, but there was no significant difference between the robot and
the human observer conditions. This suggests that people regard robots as social
beings. After the experiment, the subjects were asked to fill a survey in which
they gave higher observation impression scores for the robot condition than the
human observer, implying that they thought someone else was watching through the
eyes of the robot or due to novelty effects leading to distraction.
Following the findings from social facilitation literature, we decided to explore
the mere presence of two robotic platforms (the Aldebaran NAO and Pepper)
through a social facilitation task. We anticipated that there would be
a difference between the two platforms due to their appearance that would
be useful to make other HRI researchers aware of.
While the studies aimed to compare the social facilitation of two different
robots, it was important to establish two baselines first: one with no observers,
and one with the social facilitation elicited by a human. This
would essentially be a first step in replicating the finding from psychology.
Assuming this replication was successful, the robots could then be tested to
see how they compare both with each other and our psychology-inspired
baselines.
We ran two distinct studies, with a total of three different tasks.
Because no effect could be found between the alone condition and the human
condition in any of our tasks, we did not actually pursue the studies to
include the robots.
Social Facilitation: First Attempt
\label{sec:first}
The first study was run between-subjects with two conditions: alone condition
against human-presence. Participants were recruited on the university campus and taken
to a room in the campus library for the experiment. The experimenter would take
the participant to the room and tell them to follow instructions on the tablet,
then the experimenter would leave. In the human observer condition, a second
experimenter would already be sitting in the room and would remain there for the
duration of the experiment (as per Figure \ref{fig:setup}).