The Effects of Physical - Spatial Measures of Urban Streets on Pedestrians Emotional Responses Using EEG

The environment can cause positive and negative emotions in citizens. Emotions are important due to their impacts on people’s behaviors, because emotions make up a main component of social behavior, and extraction of emotional responses is one of the best ways to understand different fields of experience and perception. Nowadays, mental health problems and the emphasis on increasing social interactions have led to more and more concern for the subject of emotions, but the impact of physical-spatial factors has received less attention from the conducted studies. The aim of this study is to investigate the effect of the physical-spatial measures of urban streets on pedestrians’ emotional responses by placing the individual in a pseudo-real environment. Moreover, this study makes possible the use of a new neural measurement tool in urban studies and evaluates its accuracy.

Theoretical Framework:

The review of previous studies demonstrated that the environmental parameters that can affect emotion include non-physical human factors on the one hand and physical ones on the other. The physical factors that make up the subject of this research can be divided into two categories: 1- non-artificial factors, i.e. green space, and 2- artificial factors, which include the size and enclosure of the space, the shape and form of the space, the characteristics of the surfaces including architectural style, the color and texture of materials, and the variation in spatial sequences. Given the number of studies conducted on the effect of natural factors and certain characteristics of surfaces in the field of architecture, the present research examined four physical parameters.

Ten of the most important physical-spatial variables that make up different states and types of the spatial structure of an urban street, which can affect the individual emotions of pedestrians, were selected for investigation and used to design 18 tests. The research was conducted with a combined method consisting of: 1- a self-report method of Self-Assessment Manikin (SAM) images and 2- a neurological method using electroencephalography. In the EEG method, the single-channel MindWave MW001 headset, produced by Neurosky, was used as the instrument. The research population included 50 students of Tarbiat Modares University. The research was conducted with the help of controlled experiments using the mobile digital 3D modeling technique, which makes it possible for people to navigate the virtual street in the city. After the data extracted by the health and Stroop tests were confirmed, the data analysis was made using a quantitative-statistical method.

The findings regarding the shape and form of the space demonstrated that people feel more pleased in curved streets than in straight streets, and there is greater arousal in streets of the former than the latter shape. However, the level of control in a straight street is higher than that in a curved or spiral street. As for the size and enclosure of the urban space, the results indicated that there is greater pleasure in a street with medium enclosure (1:2 and 1:1) than in one with low or high enclosure (1:4 and 1:1.2), but streets with medium enclosure exhibit less arousal. Spaces with less enclosure cause people to have more control over the space. The results also demonstrated that the pleasure and arousal experienced by people is increased by the existence of the square as a spatial element and a landmark building as a physical element, permeability in the spatial structure of the street and brokenness in the path, and variation in the landscape of the street. It was only in the street with physical retraction and protrusion that no effect on arousal was observed, although the level of pleasure should increase. Moreover, the results indicated that the pleasure in the street with the curved corner was greater than that with the other forms. However, the shape of the street corner exhibits no effect on the arousal. Furthermore, the walls that are completely three-dimensional exhibit greater pleasure and arousal than those featuring walls with two-dimensional and three-dimensional rhythms. Finally, the walls that are completely two-dimensional have the least pleasantness and arousal. There is a higher level of control in the street with 2D rhythms than in that with 3D rhythms. The results also showed that visual permeability in the physical structure of the street increases the arousal and control of the space, but it has no effect on the pleasure. Another result of this research is that there is 75% conformity in the results obtained from the two methods of SAM and EEG, which demonstrates that the data (EEG) extracted from the device can extract people’s emotions well. 

In general, the current research confirms the results of previous studies, but it precisely demonstrated by measuring the extracted neural data that the levels of emotional pleasure, arousal, and control are affected by the shape and form of the street, the size and enclosure of the street space, the presence of a spatial and physical element that creates attention and emphasis in the street, permeability in the spatial structure of the street, rotation along the street and perspective change along the path, two and three-dimensional wall street rhythms, and the shape and form of the corners of the street intersection. However, physical indentations and protrusions exhibit no effect on arousal, and visual permeability has no effect on pleasure. In addition, the results showed that the EEG data extracted from the headset (MindWave MW001) used in this study could well capture the emotions of individuals, thus making up a proper potential tool for evaluation of environmental design interventions in the field of architecture and urban planning. The results of the present study, which indicate the psychological effects of urban design of a street, help to select and design the appropriate elements and physical characteristics of the space, increase positive emotions and reduce negative emotions, and ultimately improve the mental health of citizens.