One percent ability and ninety-nine percent perspiration: a study of a Japanese memorist

In 1987, Hideaki Tomoyori, a Japanese memorist, set a world record for reciting the first 40,000 digits of pi. The authors report results from a series of tests that give a view of Tomoyori's memory performance compared with that of a control group, matched for age and educational level. He showed very good scores on tasks with digits, such as digit memory span tasks and 5 x 5 number matrix learning, although some of the control participants were nearly as good. In contrast, his performance was not particularly good for learning word lists and story recall. Overall, his performance on the tasks does not suggest that he has superior cognitive abilities. We believe that his extraordinary memory performance in reciting the digits of pi results from his effective use of a combination of digit-syllable transformations and imagery mnemonics developed from extensive practice. These results are consistent with the skilled memory framework.     

Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans

This study investigated whether 12 participants with color-vision deficiency had superior visual discrimination of color-camouflaged stimuli shown on a computer screen compared with 12 participants with normal trichromatic vision. Participants were asked to distinguish a circular pattern from other patterns in which textural elements differed from the background in orientation and thickness. In one condition, stimuli were single-colored, green or red; in the other condition, stimuli were color camouflaged with a green and red mosaic overlaid onto the pattern. Color-vision deficient participants selected the correct stimuli in the color-camouflaged condition as quickly as they did in the single-colored condition. However, normal color-vision participants took longer to select the correct choice in the color-camouflaged condition than in the single-colored condition. These results suggest that participants with color-vision deficiency may have a superior visual ability to discriminate the color-camouflaged stimuli.     

Vocal recognition of owners by domestic cats (Felis catus)

Domestic cats have had a 10,000-year history of cohabitation with humans and seem to have the ability to communicate with humans. However, this has not been widely examined. We studied 20 domestic cats to investigate whether they could recognize their owners by using voices that called out the subjects’ names, with a habituation–dishabituation method. While the owner was out of the cat’s sight, we played three different strangers’ voices serially, followed by the owner’s voice. We recorded the cat’s reactions to the voices and categorized them into six behavioral categories. In addition, ten naive raters rated the cats’ response magnitudes. The cats responded to human voices not by communicative behavior (vocalization and tail movement), but by orienting behavior (ear movement and head movement). This tendency did not change even when they were called by their owners. Of the 20 cats, 15 demonstrated a lower response magnitude to the third voice than to the first voice. These habituated cats showed a significant rebound in response to the subsequent presentation of their owners’ voices. This result indicates that cats are able to use vocal cues alone to distinguish between humans.     

Fluctuations of answer and confidence rating in a general-knowledge problem task: Is confidence rating a result of direct memory-relevant output monitoring?

In order to examine whether confidence rating is a result of direct memory-relevant output monitoring, a general-knowledge test was used. A question set was answered in experimental session 1, and the same question set was employed in session 2. Subjects chose one answer from two alternatives. No significant difference in answer accuracy was found between sessions, which suggests that identical information processing was carried out, and that any difference between sessions was based on probabilistic fluctuation. The major results were as follows: (a) In both sessions, answer accuracy was an increasing function of confidence. (b) Answer-change rate (rate of different answers to the same question between sessions) decreased monotonically with confidence. (c) The distributions of confidence rating in session 2, conditional on the rating in session 1, were nearly identical in no-answer-change and answer-change cases. These results suggest that confidence rating is not a result of monitoring memory-relevant output itself but an estimation of possibility of answer fluctuation.     

Perceptions of the Concept of Mutation among Family Members of Patients Receiving Outpatient Genetic Services and University Students

Our objectives were to investigate: (1) relationships between perceptions of various terms regarding mutation and the depth of knowledge regarding mutation among family members of patients receiving genetic outpatient services, and (2) differences in perceptions of the term “gene mutation” for family members versus university students. Fifty-eight family members and 178 university students responded to two questionnaires: Impressions regarding the term, and Knowledge about the concept of mutation. Factor analyses were conducted to determine the factor structure of ratings of the terms, and two-way analyses of variance [(1)Term, (2)Group × Knowledge] were conducted to examine differences in perceptions of the terms as measured by scores for each extracted factor. Family members had a significantly more negative perception of the term “gene mutation” than “gene change” and a less negative perception of the term “gene mutation” than “gene lesion”; they had significantly more negative perceptions of the term “gene mutation” than did university students.     

The Problem of local optimality with OSMOD

The possibility of obtaining locally optimal solutions with categorical data is pointed out for the original version of OSMOD development by Saito and Otsu. A revision of the initialization strategy in OSMOD is suggested, and its effectiveness in diminishing this possibility is demonstrated.     

Demonstrating a wordlikeness effect on nonword repetition performance in a conduction aphasic patient

The purpose of this study was to identify the nature of the deficit for a conduction aphasic patient in order to evaluate two different theories of conduction aphasia. First, a conduction aphasic patient FS was tested on auditory word-pair discrimination, word-repetition, and picture-naming. The results of these tasks indicated that her deficit was likely to be post-lexical rather than perceptual or lexical. Next, we examined her repetition performance for two types of nonwords (high-wordlike and low-wordlike nonwords) to distinguish the two theories. FS exhibited a wordlikeness effect: she produced more correct moras and more correct combinations of moras for high-wordlike nonwords than low-wordlike nonwords. We conclude that she had difficulty in maintaining stable phonological representations of verbal materials in the output buffer.