Experts and Novices Use the Same Factors–But Differently–To Evaluate Pearl Quality

Yusuke Tani,Michiteru Kitazaki,Shigeki Nakauchi,Takehiro Nagai,Kowa Koida,Chris I Baker

doi:10.1371/journal.pone.0086400

Yusuke Tani, Michiteru Kitazaki + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0086400

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Journal: PloS one	Publication Date: Jan 22, 2014
Citations: 35	License type: CC BY 4.0

Affiliation: Toyohashi University of Technology, Yamagata University

Abstract

Well-trained experts in pearl grading have been thought to evaluate pearls according to their glossiness, interference color, and shape. However, the characteristics of their evaluations are not fully understood. Using pearl grading experiments, we investigate the consistency of novice (i.e., without knowledge of pearl grading) and expert participants’ pearl grading skill and then compare the novices’ grading with that of experts; furthermore, we discuss the relationship between grading, interference color, and glossiness. We found that novices’ grading was significantly less concordant with experts average grading than was experts’ grading; more than half of novices graded pearls the opposite of how experts graded those same pearls. However, while experts graded pearls more consistently than novices did, novices’ consistency was relatively high. We also found differences between the groups in regression analyses that used interference color and glossiness as explanatory variables and were conducted for each trial. Although the regression coefficient was significant in 60% of novices’ trials, there were fewer significant trials for the experts (20%). This indicates that novices can also make use of these two factors, but that their usage is simpler than that of the experts. These results suggest that experts and novices share some values about pearls but that the evaluation method is elaborated for experts.

Highlights

Pearls are known as jewels from the bottom of the sea
We judged the concordance of each participant’s rank ordering as whether it was categorically concordant with the reference rank; this was because experts’ daily work is to categorize pearls according to their quality
The group averages approached 0.773 (SD = 0.163) for experts and 0.522 (SD = 0.192) for novices, and there was a statistical difference between these averages (Figure 4B; an independent two-sample t-test, t(17) = 2.832, p = 0.012, d = 1.39)

Summary

Introduction

Pearls are known as jewels from the bottom of the sea Their mystique from being produced by shellfish and their lustrous iridescence has attracted many people worldwide. The pearls produced by Akoya pearl oysters (Pinctada fucata martensii) have superior luster and impressive iridescence. In addition to these two features, their size, roundness, and the existence of scars or pocks are the key features inspected by farmers, traders, and craftsmen, who are collectively addressed as ‘‘experts’’ [1,2,3]. This situation suggests interesting questions: How do experts use visual information to evaluate pearls? This situation suggests interesting questions: How do experts use visual information to evaluate pearls? What do they learn? What supports this tacit agreement between experts and novices?

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Results

Conclusion