Verification of Fitts' Law in Different Gravitational Environments
- Paper number
IAC-06-A1.3.08
- Author
Dr. Gianni Ciofani, Scuola Superiore Sant' Anna (SSSUP), Italy
- Coauthor
Dr. Vito Lombardo, Scuola Superiore Sant' Anna (SSSUP), Italy
- Coauthor
Dr. Daniele Mazzei, University of Pisa, Italy
- Coauthor
Dr. Antonio Migliore, University of Pisa, Italy
- Coauthor
Prof. Maria Chiara Carrozza, Scuola Superiore Sant' Anna (SSSUP), Italy
- Coauthor
Mr. Paolo Dario, Scuola Superiore Sant' Anna (SSSUP), Italy
- Coauthor
Dr. Silvestro Micera, Scuola Superiore Sant' Anna (SSSUP), Italy
- Year
2006
- Abstract
Fifty years ago Paul Fitts proved that the time (MT, Movement Time) required to complete basic tasks such as pointing movements is somehow related to the level of knowledge of the specific target to reach. The Fitt’s law says that MT=a+b ID, where ID is an “information index” related to the distance of the target (D), and to its principal dimension (W), according to the following Equation: ID=log(D/W+1). The law has been found to have relevant applications in several fields such as computer ergonomics, since it allows to define an index of difficulty and consequently to evaluate the feasibility of the development of different interfaces. The exponential development of the space research and the always greater time spent by human beings under microgravity conditions has led in the last few decades to further detailed studies in microgravity with particular attention to neurological and physiological adaptations of human beings exposed to long permanencies in zero gravity environments. However, the attention towards ergonomics in space applications may be further developed, considering the great impact that this could have in microgravity HCI engineering. Even if ergonomics is becoming more and more popular and Fitts’ law has been largely proved in the earth gravitational environment, no experiments have been carried out so far in other gravitational conditions (i.e. microgravity and hypergravity). The aim of this manuscript was to compare the results obtained in different gravitational environments (0,1,1.8g): this is the first attempt to analyse the gravity-dependent modification of the ergonomic Fitts’ law. The experiment has been performed on a Airbus 300 owned by Novespace during the 8th ESA Student Parabolic Flight Campaign held in Bordeaux. An experimental apparatus has been developed to allow the subjects to interact with some luminous targets fixed on a vertical panel and register data related to time of reaching and position of the target. The data acquired in Earth gravity conditions (1g) perfectly agree with the Fitts’ law for each of the four subjects of the experiment. The data acquired in microgravity conditions (0g), and in hypergravity conditions (1.8g), appear extremely variable for the four subjects of the experiment. Such very different behaviours could be due to the different psycho-physical impact that the variations of gravity could have on each of the subjects. So great discrepancies could not be present in subjects gotten used to this kind of experiences. After evaluating the ID parameter for every single task we fitted the mean values of MT against ID itself. For earth gravity data results are in complete agreement with MT = a + b ID, but for 0g and 1.8g data we needed a third order polynomial fitting:
MT = a+ bID+ cID 2+ dID 3 (1) .
- Abstract document
- Manuscript document
IAC-06-A1.3.08.pdf (🔒 authorized access only).
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