A PSYCHOPHYSICAL STUDY OF DIFFICULTY RATING IN ROCK CLIMBING

The competitive evolution of rock-climbing has meant that the rating s cale of difficulty (RSD) has taken a central role in the organisation of this activity. However this scale is based on evaluative mechanisms , and little is known about its validity or metrical properties. If we accept that RSD has been historically created by the accumulation of expert's judgement, we can suppose that RSD properties are related to individual processes of judgment. An experiment was conducted with the aim of testing this hypothesis. 15 highly-skilled climbers partecipat ed in the experiment. They had to perform 27 climbs on an artificial c limbing wall. They were asked, after each path, to rate its difficulty according to the RSD. Furthermore, subjects were asked to estimate, u sing the magnitude estimation method, difficulty, exertion, and requir ed accuracy. Electromyographic data were collected on the right upper limb, with the aim of evaluating expended exertion. Results showed tha t rating of objective difficulty, and perceived difficulty as an expon ential function of RSD. These results are discussed in relation with t he psychological models of judgement.