Assessing individual differences in psychophysical functions

Abstract

Individual differences in psychophysical data are examined in an olfactory experiment using a group of sixteen children (9 year olds) and three different techniques: magnitude estimation (ME), reglets or sticks (RE) and finger span (FS). From the responses given in the three techniques Steven's functions were calculated. Group and individual fits to the power law are analyzed. Comparisons of all individual curves were also done and consistency of the subjects responses across techniques was examined. Results show that: (1) while group data fit to the power law, individual data, in general, do not; (2) individual differences are found in both slopes and intercepts and (3) subjects are consistent in their judgments across techniques. These results might be interpreted in a sensory and cognitive context. Further research is needed to identify the specific contribution of sensory and cognitive sources to the individual differences in the psychophysical function.

An Experimental Test of the Accumulated Copying Error Model of Cultural Mutation for Acheulean Handaxe Size

“…Our aim here is to provide an explicit experimental test of Eerkens & Lipo's ACE model of artifact transmission. Although the assumptions of their model are based on previous experimental findings from psychophysics [28] , from where their 3% copying error assumption is derived, it is unclear (i) whether this 3% error threshold is uniform across a large population of individuals, or whether there is inter-individual variation in this threshold value (especially given previous findings of substantial individual variability in some perceptual psychometric functions [29] – [30] ), and thus how any inter-individual variation affects the robustness of the model; (ii) whether this 3% threshold, originally obtained for simple lines or abstract geometric shapes, also applies to more realistic artifact shapes; and (iii) whether it is valid to simply extrapolate a single individual's perceptual error along successive transmission episodes, or whether there are unexpected dynamics introduced by the compounding of individual errors (Hamilton & Buchanan [31] , for example, argued that the compounding of errors causes chains to decrease in size, on average).…”

Excavaciones en el sitio de Uquira, valle de Asia

“…Según Coello, la ubicación del sitio responde a la existencia de ricas minas de metales preciosos ubicados en los caseríos de Cata, Hunchor y La Yesera, que se sustentaría por la ocurrencia de poblados que, posiblemente, se ocupaban de las minas situadas en las quebradas cercanas a esos caseríos. Además, es importante por su posición geográfica en el valle, pues «[…] se comunica con sus valles vecinos por dos quebradas; hacia el sur (Quilmaná por la quebrada de San Andrés) y al norte (La Vuelta) por la quebrada de Hunchor» (Coello 1991).…”