A preliminary field study of sitting comfort and easy chairs with a new observational method

Most studies concerned with easy chairs have been laboratory-based, and therefore a need exists for information concerning the behaviour of sitters in 'natural' surroundings. Such a behavioural study requires a method of recording movement and postures which enables a detailed written record to be made at least as fast as the behaviour is occurring. The Benesh Movement Notation, which satisfies this requirement, is described and used to record the behaviour of sitters in the public lounges of hotels. The reliability and validity of this recording method is assessed. Evidence from the behavioural study shows that there are important constituents in the environment other than the chair, which affect the sitter's behaviour and posture. The sitter's behaviour is considered to be hierarchically organised; the activity of a sitter largely dictates his orientation and the chair dictates which posture can be adopted within that orientation. It is suggested that the chair (and other constituents of the environment) maintain the sitter at a level of 'activation' suitable for the current activity, however evidence for this is not conclusive. An easy chair must be designed to facilitate the activity of the sitter. The observational study shows that conversation occurs frequently between sitters and that the postures they adopt while talking are due to the need to generate and receive the non verbal signals which accompany speech. The nature of 'comfort' and 'discomfort' is discussed, and a distinction is drawn between positive comfort and the absence of discomfort. The subjective assessment of discomfort is also investigated and two experiments are reported. The first shows’ that cross modality matching of subjective feelings of discomfort with ;the force exerted on a hand grip, is a reliable and valid technique for comparing the discomfort of different chairs. The second experiment produces the function relating the force on the hand dynamometer to the score on a 'comfort' rating scale.