Enlarged Interior Built Environment Scale Modulates High-Frequency EEG Oscillations

Experimental design and setup. A, Isometric view of conditions. Participants were presented with eyes open resting state, followed by four randomized scale conditions. Each scene lasted 2 min, between which the resting state was displayed while the participant completed a self-report assessment of emotion. B, Floor plan indicating the position of items in the experiment. IEQ variables were measured continuously, and all recording equipment was positioned outside of the participants field of view. C, Diagram of equipment fitted to participant including stereoscopic tracking glasses, EEG system, respiratory belt, SCR finger cradles, and ECG electrodes. Diagrams are representative, not drawn to exact scale.

Significant differences between the control and extra-large condition for EEG power spectral density was found in the β bandwidth. To illustrate the differences, we have plotted EEG topographies and boxplots with quartile ranges and medians for the overall power spectra in the β, low-γ, and high-γ bandwidths. Note the Cz site has been interpolated for this figure. β 13–29 Hz (A), low-γ 30–45 Hz with amplitude range (B), and high-γ 55–70 Hz (C).

Significant differences in EEG low-γ frontal midline power were found. A, Power spectra plot showing power (dB) across frequencies. The low-γ bandwidth (30–45 Hz) and high-γ bandwidth (55–70 Hz) are highlighted with the gray shading box. The dip represents the 47- to 53-Hz notch filter applied to remove electrical interference from the CAVE environment. B, C, Boxplots with quartile ranges and medians to show increased γ midline power spectra. Each data point overlaid represents a participant’s averaged response from the 2-min exposure.

Physiological measures between the resting-state, small, control, large, and extra-large conditions. A–F, Boxplots with quartile ranges and medians for physiological measures analyzed using raw values. Each data point represents a participant’s averaged response from the 2-min exposure. Significance values (FDR-corrected) from the data after transform and removal of outliers have been superimposed to indicate where significant differences were found. All participants were exposed to the resting state first, before the randomized conditions. We did not detect a difference between the control and scale conditions; however, significant differences were detected between the resting-state and built environment scale conditions were found in measures analyzing the change in range, such as maximum–minimum slope for SCR and the RMSSD for HRV.

Correlations between self-assessment and physiological response. (Top row) Heatmap of the aggregated self-report responses across participants for pleasure, arousal, and dominance. (Middle row) The pictorial scale on the x-axis depicts the SAM dimensions of pleasure, arousal, and dominance. (Bottom row) Correlations were used to understand if a relationship between physiological response and self-report could be found for pleasure, arousal, and dominance. The data was obtained from averaging the response to built environment conditions and obtaining the absolute difference to the resting state condition for SCR Mx-Mn and the ± value from each domain in the self-assessment manikin.

Exposure order and comfort conditions. All IEQ data are organized by calendar day the reading was collected on (x-axis). Multiple points represent the number of participants from each day. Measurements stratified by height data were required to accommodate differences in temperature and air velocity.