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.     

Experimental study on co-evolution of categorical perception and communication systems in humans

In this paper, we present an experiment that integrates a semiotic investigation with a dynamical perspective on embodied social interactions. The primary objective is to study the emergence of a communication system between two interacting individuals, where no dedicated communication modalities are predefined and the only possible interaction is very simple, non-directional, and embodied. Throughout the experiment, we observe the following three phenomena: (1) the spontaneous emergence of turn-taking behaviour that allows communication in non-directional environments; (2) the development of an association between behaviours and perceptive categories; (3) the acquisition of novel meaning by exploiting the notion of complementary set theory.     

Crystal structure of a hexagonal phase and its relation to a quasicrystalline phase in Zn-Mg-Y alloy

The crystal structure of a Zn-Mg-Y hexagonal phase, considered to be related to that of the quasicrystalline phase, has been determined by single-crystal X-ray diffraction. The atomic model, refined to a final R value of 0.027, has the composition Zn65.22Mg27.92Y6.86 and 92 atoms in a unit cell with lattice constants a = 14.579(2) A and c = 8.687(1) A and the space group P63/mmc. The Y atoms are situated at two different sites; one is fully occupied by Y atoms, while the other is shared with Mg atoms. The structure can be characterized by a layer structure stacked along the c axis, and also viewed as a columnar structure composed of fused Friauf polyhedras sharing hexagonal rings. The similarity of this hexagonal phase to the MgZn2 phase is shown. The structural relationship between this hexagonal phase and the icosahedral phase is also discussed.     

Intergroup retaliation and intra‐group praise gain: The effect of expected cooperation from the in‐group on intergroup vicarious retribution

Intergroup vicarious retribution is the phenomenon whereby, after an out‐group member attacks an in‐group member, a member of the victim's group retaliates against a member of the perpetrator's group. This study examined the effect of expected cooperation from the in‐group on intergroup vicarious retribution through intra‐group reputation based on praise gain and exclusion avoidance. In the experiment, we conducted a one‐on‐one match in which, after participants learned that an out‐group member (as the winner) had imposed a fine on an in‐group member (as the loser) in a previous round, winning participants were allowed to impose an arbitrary fine on the other losing out‐group member. As a result, participants imposed a larger fine on their out‐group member opponent in retaliation when they were expected by in‐group members to cooperate than when such cooperation was not expected. Furthermore, participants regarded a fine as intra‐group cooperation. Since a path analysis revealed a mediating effect of praise gain, but no mediating effect of exclusion avoidance, expected cooperation from in‐group members facilitated vicarious retribution because those involved in retribution sought praise from other in‐group members. These findings suggest that the intra‐group reputation dynamics of expected cooperation and praise gain escalate intergroup conflict.     

The Organization of Extrinsic Neurons and Their Implications in the Functional Roles of the Mushroom Bodies in Drosophila melanogaster Meigen

Although the importance of the Drosophila mushroom body in olfactory learning and memory has been stressed, virtually nothing is known about the brain regions to which it is connected. Using Golgi and GAL4–UAS techniques, we performed the first systematic attempt to reveal the anatomy of its extrinsic neurons. A novel presynaptic reporter construct, UAS-neuronal synaptobrevin–green fluorescent protein (n-syb–GFP), was used to reveal the direction of information in the GAL4-labeled neurons. Our results showed that the main target of the output neurons from the mushroom body lobes is the anterior part of the inferior medial, superior medial, and superior lateral protocerebrum. The lobes also receive afferents from these neuropils. The lack of major output projections directly to the deutocerebrum’s premotor pathways discourages the view that the role of the mushroom body may be that of an immediate modifier of behavior. Our data, as well as a critical evaluation of the literature, suggest that the mushroom body may not by itself be a “center” for learning and memory, but that it can equally be considered as a preprocessor of olfactory signals en route to “higher” protocerebral regions.     

Self-motion perception compresses time experienced in return travel

It is often anecdotally reported that time experienced in return travel (back to the start point) seems shorter than time spent in outward travel (travel to a new destination). Here, we report the first experimental results showing that return travel time is experienced as shorter than the actual time. This discrepancy is induced by the existence of self-motion perception.     

The mental number line in depth revealed by vection

To explore how numbers are represented in depth in our mental space, we asked participants to sequentially speak random numbers while they observed forward/backward vection. We found that participants tended to generate larger numbers when they perceived backward self-motion. The results suggest that numerical magnitudes were topographically mapped onto our mental space from front to rear in an ascending order.     

Attentional load inhibits vection

In this study, we examined the effects of cognitive task performance on the induction of vection. We hypothesized that, if vection requires attentional resources, performing cognitive tasks requiring attention should inhibit or weaken it. Experiment 1 tested the effects on vection of simultaneously performing a rapid serial visual presentation (RSVP) task. The results revealed that the RSVP task affected the subjective strength of vection. Experiment 2 tested the effects of a multiple-object-tracking (MOT) task on vection. Simultaneous performance of the MOT task decreased the duration and subjective strength of vection. Taken together, these findings suggest that vection induction requires attentional resources.     

Eyes pursue moving objects, not retinal motion signals

For smooth-pursuit eye movements, a moving target is necessary, but we show that it is not sufficient. Observers pursued targets that appeared to move in one direction even though they really moved in another. Changes in perceived direction did not disrupt pursuit eye movements, but motion-based failures in object parsing did.     

Inhibition of vection by red

We investigated the effects of colors on vection induction. Expanding optical flows during one’s forward self-motion were simulated by moving dots. The dots and the background were painted in equiluminant red and green. Experiments 1 and 2 showed that vection was weaker when the background was red than when the background was green. In addition, Experiment 3 showed that vection was weaker when the moving dots were red than when the dots were green. Experiment 4 demonstrated that red dots on a red background induced very weak vection, as compared with green dots on a green background. In Experiments 5 and 6, we showed that the present results could not be explained by a luminance artifact. Furthermore, Experiment 7 showed that a moving red grating induced weaker vection than did a green one. We concluded that a red visual stimulus inhibits vection.