Research conducted by Pheasant "et al." has shown that when individuals make tranquillity assessments based on a uni-modal auditory or visual sensory input, they characterise the environment by drawing upon a number of key landscape and soundscape characteristics. For example, when making assessments in response to visual-only stimuli the percentage of water, flora and geological features present within a scene, positively influence how tranquil a location is perceived to be. Likewise when responding to uni-modal auditory stimuli, the perceived loudness of biological sounds positively influences the perception of tranquillity, whilst the perceived loudness of mechanical sounds have a negative effect. However, when presented with bi-modal auditory-visual stimuli the individual soundscape and landscape components alone no longer influenced the perception of tranquillity. Rather configurational coherence was provided by the percentage of natural and contextual features present within the scene and the equivalent continuous sound pressure level (LAeq).