Engaging the Senses : The Potential of Emotional 2 Data as a new Information Layer in Urban Planning 3

Although our emotional connection with the physical urban setting is often valued, it is 11 rarely recognised or used as a resource to understand future actions in city planning. Yet, despite the 12 importance of emotion, citizens’ emotions are typically seen as difficult to quantify and 13 individualistic, even though knowledge about people’s response to space could help planners 14 understand people’s behaviours and learn about how citizens use and live in the city. The study 15 explores the relationship between the physical space and emotions through identifying the links 16 between stress levels, and specific features of the urban environment. This study aims to show the 17 potential of integrating the use of galvanic skin response (GSR) within urban spatial analysis and city 18 planning, in order to address the relationship between emotions and urban spaces. This method 19 involved participants using a (GSR) device linked to location data to measure participant’s emotional 20 responses along a walking route in a city centre environment. Findings show correlations between 21 characteristics of environment and stress levels, as well as how specific features of the city spaces 22 such as road crossing create stress ‘hotspots’. We suggest that the data obtained could contribute to 23 citizens creating their own information layer an emotional layerthat could inform urban planning 24 decision-making. The implications of this application of this method as an approach to public 25 participation in urban planning are also discussed. 26


Introduction -Sharing Cities
Cities are increasingly the focus of new forms of participation, enabled by technological devices and platforms [1], such as crowdsourcing where citizens create, adapt and exploit data [2].
Conventional citizen participation methods in city planning include referenda, public hearings, public surveys, charettes, public advisory committees or focus groups which require the participants to be physical present at particular time and place.These enable citizens' to have input into the process, but practical problems of participation such as limitations of time and costs in the policy making process, or apathy among citizens are recognised challenges [3].Digital technologies can address some of the issues of participation in the urban planning process by enabling a more accessible system for the public to shape their neighbourhood's future [4].Munster et al. [5] outlines many advantages of digital participation which include the utilisation of wider pool of knowledge through broader audience and participants, providing for an interactive and communicationoriented planning process, offering new perspectives for designers and planners and also "transforming planning work into an iterative, agile work process, in contrast to sequential and linear workflows that have shaped urban design practice in the past" [5].In order to truly involve inhabitants in urban planning, a central aspect is to capture their concerns, agreement, and ideas and to react appropriately.However, the explosion of digital media means that a huge amount of qualitative and subjective feedback data from citizens are also being produced.Analysing these data is where the actual challenge lies.Crivellaro et al. [6] have looked at how local people get together online through Facebook to mobilise around a local social movement.They recognised the importance of forming a like-minded community, but it also acknowledged the struggle of the group to translate their emotions to the authority and decision makers.Hasler et al. [7] in another research found that the multiplication and diversity of contributions by citizens through digital participation increases complexity which means that prioritising relevant data can be problematic.This illustrates how technologies can facilitate discussions that are planning-related, but turning them into actionable policies proven to be difficult.
In this paper we look at the potential of emotional data for enabling participation in urban planning, that contributes towards a shared cities approach.This takes a model of participation that is termed 'co-production' whereby 'citizens perform the role of partner rather than customer in the delivery of public services' [8].Mclaren and Agymen present a model for collaboration and sharing around the city in their book 'Sharing Cities' and describe how they see "the increasingly blurred nexus between urban-and cyberspace enabling transformation -this time in the political domain.These spaces are fundamentally important for forms of participation invented and controlled by the people" [9].In order to do this, we first review the literature on the urban planning process, showing how the development of the discipline has sought to enable citizen participation.
We map this against Arnstein's 'Ladder of Participation' to highlight how much of this participation typically does not enable citizens to control and act in the process, and is therefore often tokenistic.
We then outline the potential of incorporating digital tools for participation, and in particular the value of incorporating emotional data as a way of capturing a more person-centric understanding of urban space.In the study described in the paper, we use a method where a small number of participants used a galvanic skin response (GSR) linked to location data to record stress levels in a walk through an urban city centre space with different characteristics.The findings aim to explore whether this emotional data might have benefit for enabling new models of more data informed participation in urban planning processes.

The Challenge of Participation in the Urban Planning Process
"Cities have the capability of providing something for everybody, only because, and only when, they are created by everybody" [10] Many people now live in cities, but despite Jacob's plea above, very few participate in how they are created, designed and planned.Therefore, the challenge we seek to make some contribution to with this study is 'how to enable meaningful participation in the urban planning process'?In order to do this, we first provide some context on how urban planning evolved and the developing role of participation.If we look back to the origins if urban planning in the western world in the early 20th Century, the process was heavily influenced by the rational-comprehensive approach where the planning sequence involves: a survey of the region, an analysis of the survey, and finally the development of the plan [11].Hall [12] argued that Geddes "gave planning a logical structure" by developing the survey-analysis-plan sequence of planning.However, this method of planning has been criticised to be too dictatorial -seeing the planner as "the omniscient ruler, who should create new settlement forms without interference or question" [12] as well as being too reductionist as planners have to make assumptions and predictions which required them to have complete certainty [13].This then caused the planners to proceed on the basis of simplifying the world around them which later led to a lot of failure of the predictions [13].The failures of the rational-comprehensive approach in urban planning led it to being succeeded by synoptic planning approach in 1960s and Hall argued that this change represents a fundamental shift in the role of the planners and their relationship with the public.However, Faludi [13] argued that this early form of participation was still based on the assumption that the society is homogenous -implying the homogeneity of interest.This means that participation is only required to validate and uncritically legitimise the goals of planning and any objection to planning proposal tends to be stigmatised [13].
Even when public participation has become an integral part of current urban planning process, Innes and Booher [3] argued that they still "do not achieve genuine participation".This is because current form of public participation does not satisfy members of the public that they are being heard and often does not improve the decisions that agencies and public officials make and [3].The scepticism posed by Innes and Booher [3] to the way that current participation is being practiced could be traced back to Arnstein's widely known 'Ladder of Participation' [14].As she put it, "there is a critical difference between going through the empty ritual of participation and having the real power needed to affect the outcomes of the process" [14].The fundamental point of these criticisms was that if urban planners seek public participation, it is necessary that there be a redistribution of power [14].She regarded power in public participation as a ladder or a spectrum ranging from 'nonparticipation' through to 'degrees of citizen power' (see Figure 1), which correspond to the degree of power or control participants can exercise in the quest of shaping the outcome.The ladder outlines steps of public participation from manipulation (level 1), education (level 3), and consultation (level 4), through to sharing power through 'partnership' (level 6) and beyond.Notably, Arnstein's framework regards consultation as 'tokenism' similar to the way Innes and Booher [3] viewed the level of public participation in current urban planning process.However, Painter [15] argued against Arnstein's analysis by stating that her ladder of participation model inaccurately apprehends power i.e. it confuses 'potential power' with 'actual power' [15].While the official decision-making power may rest with institutional decision-makers in a consultation process, to regard the process as tokenistic disregards the fact that "if the exercise of influence [by participants] is effective, then this formal power is an empty shell" [15], p.23).He also argues that Arnstein's model often assume decision-making in planning occurs at a single point in the process.This ignores the fact that there is rarely an identifiable, or single, 'point of decision' in policy-making [15].The primary value of this discussion is that it exposes that participation in planning can include the exercise of both formal and informal power.Hence, having power in decision-making processes is not the only way towards achieving genuine participation as it could also be realised through ranges of other participatory activities -as long as the engagement with citizens contribute positively towards the outcome of a planning project.

Emotions and Planning
In this paper we explore whether emotional data about a particular city setting can be used to inform the urban planning process.Although the link between the built environment and human's emotional aspects in urban planning research has found a growing interest in recent years, it is still a rather new approach in the field [16].Typically in urban planning, planning is seen as an objective process, so emotion is not seen as qualities or analysis that can be meaningfully included in decision making [17].They believe that urban planners should avoid allowing emotions to influence their analysis or recommendations and this is largely due to the fact that urban planners are taught to operate in a rational manner [17].Despite the neglect of emotional aspects by many planning officials, there are also some urban planners who do recognise the importance of emotions within the field.
For example, Lynch [18] recognises the emotional aspect through its link with emotions and mental maps while Ferreira [19] has urged that emotions should be presented as constructive drives with the power to positively inspire the planner to become a more competent professional.Porter et al. [20] on the other hand have claimed that attachments to community members improve the ability of planners to understand and work with residents while Gunder and Hillier [21] have interpreted planning issues through a Lacanian psychological model which acknowledge the entire process of becoming and being a planner is typically associated with strong emotional experiences.These authors have provided a meaningful theoretical discourse in terms of acknowledging the importance of emotions within urban planning.However, the majority of them have kept their focus on the planner side of the equation rather than on the users' side.Most of them recognise that planners should positively address emotions but very few have put the emphasis on citizens' emotional interactions with the urban environments itself.This should not be the case if we were to truly understand the relationship between emotions and urban spaces.Hence, by linking it to public participations and the developments of digital tools, the next subsection will review some of the literature and studies around the spatial-emotional interactions of the city's users as its main focus to understand the significance of emotions in urban planning field.

Digital Tools as Means for Measuring Emotions
Recent technological developments have allowed the incorporation of emotions in public participation within the planning field.It also allows current urban planners to increase their understanding of the relationship between citizens and urban spaces by measuring their emotions using newly developed digital tools.Most of the studies around this topic can largely be divided into three categories based on the tools they have used to extract emotional data either through: 1) social media, 2) mobile apps, or 3) physiological wearable devices.The similarities within all of these studies and perhaps the most important one for incorporating emotional experiences in spatial analysis is the capability to cross reference emotional data with accurate locational data i.e. the ability to geolocate those data to a specific place within a city.For example, under the first category, Mislove et al. [22] extract the moods of people from different cities by mining information on social media, in this case, Twitter.
This information however tends be at a low level of granularity; it is generally at a large spatial scale such as city, state or region and not collected at a detailed spatial level, such as a street or a city centre.Nevertheless, there are other recent research on mining emotional responses towards particular spaces from social media such as Tauscher and Neumann [23] who generated sentiment maps of tourist locations.Hauthal and Burghardt [24] and Aiello et al., [25] both extract locationbased emotions from photo titles, descriptions, and tags from Panoramio and Flickr respectively to generate maps of specific streets within various cities with emotional attributes.Mody et al designed a location-based socialnetworking tool that enables users to share and store their emotional feelings about places 'WiMo' [26].They found that it was possible to create a recognisable and useable framework for gathering users individual emptional responses in a shared map interface.Key to this was defining 'places' rather than distinct geographical locations as these elicted an emotional response.Meanwhile, Zeile et al., [27] has established a dedicated algorithm to source emotional expressions from Twitter before plotting them onto the map of downtown Boston.
Some researchers have started to focus on developing mobile apps, to gather users' wellbeing and feelings and to relate them to the geographic reference of their occurrence.For example, Ettema and Smajic (2015) utilised smartphones to gather self-recorded experiences of students during a walk.
They have then later found out that the level of happiness was the highest in areas where many activities were happening and where a lot of people were around (Ettema and Smajic, 2015).
MacKerron and Mourato (2013) in their project "Mappiness" used an iPhone app to collect frequent reports of temporary happiness at random times.responses to space through mobile phones, as well as modelling, and visualizing these data.The findings indicate that environments varying according to the amount of vegetation and traffic are perceived differently, with highest positive ratings for the urban-green area, and lowest ratings in the heavy traffic urban area (Klettner et al., 2013).
While semantic analysis from social media data and citizen feedbacks from mobile apps offer subjective evaluations on emotional experience of participants, physiological emotional extraction technique using wearable devices propose the investigation of the more objective element of emotions.This is on the basis that physiological responses would provide useful indications of the users' current emotional states when they interact with the physical environment.Over the last ten years, some urban researchers have been investigating this relationship and Nold's [28] 'emotional cartography' is perhaps the most significant in laying a fundamental underpinning to explore the changes in physiology in the urban space.His "BioMapping" project done between the year 2004 to 2009 was the first to integrate GPS data with biometric human sensor data and explore the idea to visualise cartographically referenced emotional data.In the fieldworks, he gathered the change of the skin conductance levels of the participants as they walk in a number of cities using a wearable device, in this case a galvanic skin response (GSR) device, then have it mapped based on their GPS locations to describe areas in terms of emotional arousal [28].
Similar work was done by Zeile et al. [29] who mapped the stress levels of cyclists in Cambridge, Massachusetts by measuring skin conductance levels during their ride using a GSR device.Apart from that, they have also attached a video recording device to allow footages to be taken along the route in order to accurately understand what caused the physiological changes in their participants [29].A dedicated smartphone app was then used to allow geo-tagged reporting of the experiment.
Their findings include the detection of what caused negative arousal in cyclists and they found out that the triggers include dangerous intersections, physical obstacles, pedestrians crossing, cars passing close by and damaged road surface [29].They have also mapped the cycling route with all the moments of stress and triggers as well as some specific emotions based on the input from the participants and their rides.
The studies conducted by Nold [28] and Zeile et al. [29] all benefited from the use of the GSR device that offers physiological data collection of emotions of the participants.As the GSR device measures levels of emotional arousal through the change in skin conductance and resistance levels, these data can be easily quantified resulting in a more objective measure of emotions rather than just qualitative.This method is valuable since objective measurement of emotions has proven to be beneficial in terms of producing a more accurate representation of emotions.Hence, the next subsection will explore the mechanism operating the GSR device and its uses in measuring negative emotional arousal within the field.As mentioned previously, not many exploratory studies to date [28][29][30] have attempted to objectively investigate the relationship between emotions and physical environments by using physiological responses methods.Nevertheless, their work has laid important theoretical and methodological foundations for integrating the use of galvanic skin response (GSR) within urban spatial analysis and city planning, hence, presents a new model to address the relationship between emotions and urban spaces.

Materials and Methods
In this study, individual participants were asked to walk through a specific route in the city, whilst linked up to a galvanic skin response (GSR) device attached to their fingers and a GPS tracker app (Figure 2) in a backpack which they carried.

Participants
A total of 9 participants, 3 males and 6 females, aged between 23-28 years old were recruited for the study.They were selected based on the criteria that they had lived in the city for between 1-3 years, so that they had some basic equivalence in terms of the background spatial knowledge of the setting.All of them were international students at the University of Plymouth.The relatively low number of participant's means that this study is exploratory and results are presented primarily through qualitative analysis.

Setting
The route was chosen primarily because it covers three distinct areas in Plymouth City Centre.
Participants were asked to walk from Plymouth Hoe, a popular recreational park in Plymouth, continuing their walk through Armada Way, a pedestrianized area, and ending at the North Road East (Figure 4), a walk which took about twenty minutes in total.The route chosen for this study consists of three distinct areas summarized in the The route included a number of junctions with varying levels of car and pedestrian traffic summarized in the table below (see Figure 5 and Table 2): It could also be observed that seven out of nine participant's recorded the lowest stress levels (their highest level of skin resistance) at the start of the walk in Plymouth Hoe than any other area of the walking route.Their stress level gradually increased throughout the journey as they enter Armada Way and ended at the highest level at the end of North Road East.This result indicates that most participants find Plymouth Hoe park to be the least stressful area followed by Armada Way and then North Road East, where most participants find it to be most stressful.Two out of the nine participants (participant 02 and 06) on the other hand recorded their lowest stress levels when they were walking in the Armada Way.However, both of their stress levels then changed dramatically as it steeply increased when they entered the North Road East area.
Further analysis on the participants' stress levels can be made by drawing trend lines of their individual graphs for each area along the walking route.From the results it can be observed that the highest number of participants (5 out of 9 people) recorded an increasing level of skin resistance while walking through Plymouth Hoe.This further emphasises that most participants find Plymouth Hoe to be the least stressful place as their level of stress decreases as they walk through the park.
Meanwhile, as participants walk through Armada Way, five participants experienced increasing stress levels compared to the number of people who experience decreasing stress levels (4 participants).At North Road East, all of the nine participants recorded a decreasing skin resistance level.This further emphasises that North Road East is the most stressful area compared to the other two areas as all of the participant's stress levels increased as they walked along the road.Peer-reviewed version available at Urban Sci.2018, 2, 98; doi:10.3390/urbansci2040098

Change in Stress Levels at Crossings and Junctions
Another clear finding from this study is the relationship road crossings and junctions have with the change in stress levels of the participants.A typical participant is shown in Figure 7 with the crossings and stress levels indicated.The overall results (see Figure 8, 9 and 10) show that all of the crossings have at least three people experiencing a sudden increase in stress levels (a sudden drop in skin resistance level).Crossings at Citadel Road, Royal Parade, and Mayflower Street (see Figure 8) recorded the highest number of participants (i.e.all of the 6 participants) experiencing a sudden increase in stress levels.Derry Avenue crossing and junctions at New George St. and Cornwall St., on the contrary, recorded the lowest number of participants (3 participants) that experienced the sudden increase in stress levels (see Figure 9).Peer-reviewed version available at Urban Sci.2018, 2, 98; doi:10.3390/urbansci2040098 Figure 10 Overall results from all of the 6 participants with their graphs cross referenced with their GPS locational data.It could be noted that all of the crossings have at least 3 people experiencing a sudden drop in skin resistance level which equates to a sudden increase in stress levels.

Relationship between Stress Levels and the Presence of Traffic and Natural Features
These different characteristics of each type of urban space encountered on the walk provides a clear variable which allows this paper to narrow down its research i.e. the relationship between emotions and physical environment can be studied in a more explicit manner.This means that the connection emotions have with specific urban features, in this case the presence of traffics and natural features, can be established more clearly.One observation that could be made from the findings is that area which was had the most 'green' space and natural features (Plymouth Hoe) created a generally less stressful environment for the participants.In contrast, areas with relatively less green space caused participants to feel more stressed.This observation is supported by many other previous studies such as MacKerron and Mourato's [31] "Mappiness" project and Klettner et al., [32] EmoMap project which have shown that green or natural environments have positive effects on emotions.For example, Nold stated that the Greenwich Emotion Map derived from his BioMapping project could "continues to be a discussion point and is of use in identifying and solidifying local issues of concern" [28].Meanwhile, Shoval et al., [30] recognised that products of such analysis "lead to important insights into how people perceive and interact emotionally with the urban environment; it can therefore be of great use in an improved planning process" [30].Zeile et al. have acknowledged that their results can be used "as a source of information to help improve bicycle traffic planning and to identify hotspots in urban planning deficiencies" [33].There are, of course, recognized and valid issues around the ethics and nature of consent around crowdsourcing urban data.For instance Gabrys argues that 'enabling citizens to monitor their activities convert these citizens into unwitting gatherers and providers of data' that can be used for political or commercial purposes beyond that which citizens are aware of [34].But when used by the citizen for their own benefit Haklay asserts that 'the act of mapping itself can be an act of asserting presence, rights to be heard or expression of personal beliefs in the way that the world should evolve and operate' [35] Emotional data can offer a new layer of information and provide new dimensions for both urban planners and citizens to understand the city they live in.Through the identification of stress hotspots in this study, areas with high level of stress in a city could be identified and given more attention by the local's urban planning discussions.Whilst this study is small scale in terms of the number of participants, the nature of the findings does indicate that the method could be replicated with larger number of participants to increase the level of data and coverage.The understanding gained from this analysis would help create a readily available layer of information to help planners easily identify potentially problematic area within the city, even before any planning projects were even considered.
Whilst this study was undertaken in an existing city space, there is also the potential to draw some more general conclusions that could inform urban design proposals.It could therefore provide better insights of the city and its inhabitants -enabling a new citizen-centered perspective in urban planning processes.

Physiological Data for Citizen-Centric Participatory Planning
In addition to the provision of a new information layer within urban planning analysis, the gathering of citizens' emotional data through physiological responses methods could also bring forward a more human-centric approach to participation in the city planning process.Unlike traditional forms of urban planning participation such as public meetings, consultations and hearings, this study suggests that humans, as the users of a city, could provide qualitative emotional data to contribute to a participatory planning process.Jacobs [10] pointed out an important change in urban planning procedures which includes bottom up processes of participation that proactively involve citizens in urban change.This study has benefited from the use physiological sensor technology to directly, objectively and cheaply measure citizens' emotions which means that their emotional experience of the city.Scaled up, this approach would mean that a city could involve citizens in providing emotional data that would regularly provide new emotional data near real-time and as a readily available information layer to the city council.The model used in this study was for citizens to gather their own data and share it with others in order to understand their experience of the city in a more quantitative manner.
When reviewed against Arnstein's [14] 'Ladder of Participation', this method of using physiological device to gather citizens' emotional data would still fall under tokenism at either 'consultation' or 'placation' rung of the ladder.This is because participants of this study only provide emotional data input and do not have the actual power to influence how the data will be used in urban planning process.In the end, city planners still play a central role in planning decisions.
However, the lack of 'citizen power' in this participatory method could be outweighed by the fact that using physiological sensing technology such as the GSR provides an accurate and objective data resource of citizens' emotions.It could also potentially be done at scale to create a large information database.During a traditional consultation process, citizens would subjectively express concerns about a planning project and the relevant authority would re-evaluate the project based on their feedback.In this citizen sensing participatory planning approach however, there is no need to wait until a planning project is established before actions or decisions could be made.In fact, the collection of emotional data can be continuous and ongoing and can be used at any time to inform any new planning projects.Therefore, for as long as the emotional data inputs from citizens influence the outcome of any planning decisions, even without any exercise of 'power', this form of participatory process could move beyond tokenism towards Arnstein's model of 'citizen power'.

Conclusions
Current urban planning procedures view participation as a fundamental element to the process.
Nevertheless, many academics in the field have critiqued to how it is implemented, with some of them claiming that the current participation methods do not achieve genuine participation (reference here).However digital participation using technologies such as physiological sensing devices, smartphones, and GPS technology present opportunities for a more effective and human-centred approach to participatory planning.This paper explores the potential of citizen's emotional data to inform understanding of urban spaces within a participatory planning procedure.This approach benefits from the use of digital tools such as the galvanic skin response (GSR) and GPS devices to objectively measure emotional response of people to a geo-located urban space.
The study presents a potential methodological contribution in terms of the incorporation of physiological sensing device and GPS tracking technologies for objective measures of emotional data in urban environments.The results prove that there is a significant relationship between humans and the physical environments and by objectively measuring and analysing the data, this method provides innovative opportunities for urban planners to understand how citizens relate and interact emotionally to the city's urban environment.The data gathered through this approach could add a new dimension in the form of a new additional layer of information in urban planning analysis to assist urban planners in decision making process.

Figure 2 Figure 3 GSR
Figure 2 Experiment set-up consist of a GSR device, a laptop, and a backpack linked to a GPS Phone Tracker App that was used to track participants location at 1-minute intervals during the walk

PreprintsFigure 4
Figure 4 Study Route -Participants start walking from Plymouth Hoe, through Armada Way and ends in North Road East.

Figure 5 Figure 6
Figure 5 Participant's walking route -main crossings or junctions along the route

Preprints
(www.preprints.org)| NOT PEER-REVIEWED | Posted: 4 July 2018 doi:10.20944/preprints201807.0073.v1 The other 3 participants recorded generally unchanged stress levels when encountering these roads.Crossings at Citadel Road, Royal Parade and Mayflower St. are notably busier than junctions at New George St., Cornwall St., and Derry Ave.This resulted in more participants experiencing a sudden increase in stress levels at the former 3 crossings rather than at the latter 3.In fact, junctions at New George St. and Cornwall St. are at a fully pedestrianised area thus have no traffic presence.

Figure 7 Figure 8
Figure 7 Typical participant's stress graph with crossing indicated

Figure 9
Figure 9 Derry Ave.crossing and junctions at New George St. and Cornwall St. on the contrary, recorded the lowest number of participants (3 participants) that experience the sudden increase in stress levels.

table below (Table 1 )
: A mix of both pedestrianised area and traffic (with some green space and natural features) North Road East Urban road Busy road with very limited natural features

Table 1 :
Names and types of spaces along the walking route