that contribute, in unknown ways, to observed differences in scales. These biases must be removed either by properly arranging conditions in the experiment so that they do not exist or by measuring them in the experiment and later eliminating them from the data by some statistical procedure. If this cannot be done, ratio scaling techniques will be of no value to the diagnostician interested in assessing the psychological magnitude function of an individual patient. Participants at the conference strongly endorsed the view that it is important for us to develop methods for measuring unbiased psychological magnitude functions in individuals. A better understanding of individual differences within populations of people with normal and defective sensory systems will be achieved only when this goal is met.
Near the end of the conference the participants were enthusiastic about the possibility of having future conferences on ratio scaling. A number of topics were suggested for focused attention at future conferences, some of which were touched on either during paper presentations or during the 3- hour general discussion at the end of the conference. Thus, in addition to the new information presented through papers, the conference provided a forum for setting agendas for future meetings. Future conferences are likely to include such topics as the relationship between psychophysical scales and neurophysiological measurements with the specific aim of determining the neural code for stimulus intensity, the dynamics of the judgment process, which should include an assessment of the role of cognitive and sensory factors, comparisons of results obtained for intensive continua with those obtained for extensive continua, relationships between ratio scaling data and stimulus detectability data obtained either through classical or signal detection methodology, and finally methodological topics were suggested such as the reliability of measurements and measurement of the psychological magnitudes of stimuli presented to individual subjects.
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