MEASUREMENT OF PHOTOGRAPHIC QUALITY AND INDIVIDUAL DISTINCTIVENESS FOR THE PHOTOGRAPHIC IDENTIFICATION OF HUMPBACK WHALES, MEGAPTERA NOVAEANGLIAE

Accurate identification of humpback whales from photographic identification data depends on the quality of the photographs and the distinctiveness of the flukes. Criteria for evaluating photographic quality and individual distinctiveness were developed involving judgments about overall quality or distinctiveness and about specific aspects of each. These criteria were tested for the level of agreement among judges. The distinctiveness scheme was tested for the independence of distinctiveness judgments and photographic quality. Our results show that judges could agree when evaluating specific and overall aspects of photographic quality and individual distinctiveness. The level of agreement varied for different pairs of judges, and less adept judges were identified. Ability to agree on evaluations of photographic quality was independent of the experience of the judges. Overall photographic quality and overall distinctiveness were successfully predicted from more specific variables, but the agreement between judges for these was not significantly greater than the agreement for the overall measures judged directly. There was no correlation between individual distinctiveness and photographic quality for four of the five judges, but the power of this rest may be low. Analyses of photographic identification data frequently require evaluations of photographic quality and individual distinctiveness. To obtain reliable results from such analyses, evaluation schemes and judges should be tested to ensure reliable and consistent evaluations.     

USE OF INDIVIDUAL DIFFERENCES SCALING FOR SENSORY STUDIES: SIMULATED RECOVERY OF STRUCTURE UNDER VARIOUS MISSING VALUE RATES AND ERROR LEVELS

The use of Individual Differences Scaling in sensory studies has been limited because the number of pairwise comparisons in a complete design can be prohibitively large. This study examines the effect of different levels of error and missing data on recovery of true structure by Individual Difference Scaling for the normal range of assessors and stimuli (8–16) used by sensory workers. Recovery was very good for a missing value rate of 20%. It was good for 40% provided that the number of stimuli was high, but deteriorated sharply at 60% missing data. The effect of superimposing random error on to the true structure indicated that a large error rate gave poor recovery. It is concluded that up to 40% of the distances in a complete design could be excluded, provided that replicate measurements indicated error levels were not severe.     

PREFERENCES FOR SOUTHWESTERN SALTED SNACK FLAVORS: INDIVIDUAL DIFFERENCES AT THE CONCEPTUAL LEVEL AND THE CONSTRUCTION OF A PRODUCT LINE

Individuals differ in what they like, both from a sensory basis, but also from a conceptual basis. For a product to be purchased, the concept (or even the flavor name) must be acceptable just as the physical product itself must be acceptable. This paper presents the results of a study in which the panelists rated degree of interest in 12 different new flavors for a snack chip positioned at the start of the study to have a "taste of the southwest." The results show the substantial variation in acceptance for the different flavors presented as names only (viz., concepts, rather than actual products). Segmentation by attitude of consumers on the basis of the pattern of liking revealed differences among consumers, but did not show the typical opposing patterns found when sensory segmentation is done using actual products having different flavors. These individual differences require that a line of different flavors be developed. There is no simple organizing principle, however, underlying the individual differences. Thus to create the line of flavors requires a different approach. The approach selects various combinations of flavors, identifies the proportion of consumers who would accept at least one flavor of the line (so-called "satisfied consumer"), and then maximizes the number of such "satisfied consumers" for a line comprising a given number of flavors.