Hiroshi Arao

Discrete cortical regions associated with the musical beauty of major and minor chords

Previous research has demonstrated that the degree of aesthetic pleasure a person experiences correlates with the activation of reward functions in the brain. However, it is unclear whether different affective qualities and the perceptions of beauty that they evoke correspond to specific areas of brain activation. Major and minor musical keys induce two types of affective qualities—bright/happy and dark/sad—that both evoke aesthetic pleasure. In the present study, we used positron emission tomography to demonstrate that the two musical keys (major and minor) activate distinct brain areas. Minor consonant chords perceived as beautiful strongly activated the right striatum, which has been assumed to play an important role in reward and emotion processing, whereas major consonant chords perceived as beautiful induced significant activity in the left middle temporal gyrus, which is believed to be related to coherent and orderly information processing. These results suggest that major and minor keys, both of which are perceived as beautiful, are processed differently in the brain.

Does Time-Shrinking Take Place in Visual Temporal Patterns?:

The duration of a short empty time interval (typically shorter than 300 ms) is often underestimated when it is immediately preceded by a shorter time interval. This illusory underestimation—time-shrinking—had been studied only with auditory temporal patterns. In the present study, we examined whether similar underestimation would take place with visual temporal patterns. It turned out that underestimation of the same kind takes place also in the visual modality. However, a considerable difference between the auditory and the visual modalities appeared. In the auditory modality, it had been shown that the amount of underestimation decreased for preceding time intervals longer than 200 ms. In the present study, the underestimation increased when the preceding time interval varied from 160 to 400 ms. Furthermore, the differences between the two neighbouring intervals which could cause this underestimation had always been in a fixed range in the auditory modality. In the visual modality, the range was broader when the intervals were longer. These results were interpreted in terms of an assimilation process in light of the processing-time hypothesis proposed by Nakajima (1987 Perception 16 485–520) in order to explain an aspect of empty-duration perception.

Disruptive Effects in Chord Priming

Chord-priming effects were investigated in a related-prime condition, an unrelated-prime condition, and a control condition in which a noise was presented instead of a prime chord. Ten participants listened to a sequence consisting of a prime (a chord or a noise) and a target chord and then decided whether the target chord was in tune or out of tune. The interonset intervals between the prime and target chords were varied at either 1, 3, or 7 s, whereas the duration of the chords or noises was fixed at 500 ms. Responses were significantly slower with lower accuracy in the unrelated-prime condition than in the control condition, whereas responses were not significantly faster in the related-prime condition than in the control condition. The delay in the unrelated-prime condition was found at interonset intervals of 1 and 3 s, but the delay almost disappeared at the longest interonset interval of 7 s. These results cannot be fully explained by a spreading activation model that assumes a facilitation effect, but rather seem to suggest that disruptive effects occur with regard to the sensitivity to chordal tuning. /// 和音プライミング効果を，関連プライム条件，非関連プライム条件，統制条 件において検討した. 統制条件においては，プライム和音のかわりにノイズ が呈示された. 10名の被験者は，プライム (和音またはノイズ) とターゲッ ト和音を聞き，ターゲット和音のチューニングが正しいか誤っているかを判 断した. プライムとターゲット和音の立ち上がり聞の時間間隔は, 1，3， 7sのいずれかであり，和音とノイズの長さはすべて500msであった. 非関連 プライム条件における反応は, 統制条件における反応よりも有意に遅く，正 答率も低かった. 一方，関連プライム条件における反応は，統制条件におけ る反応よめも有意差がみられるほど速くはなかった. 非関連プライム条件に おける反応の遅れは，時間間隔が1, 3sのときにあらわれたが. 7sのとき にはほとんど消失した. これらの結果は，和音のチューニング感度に妨害効 果が生じていることを示唆しており，促進効果を仮定する活性化拡散モデル では完全には説明できない.

Priming effects on musical chord identification: Facilitation or disruption?

The present study examined whether priming effects on chord identification are facilitative or disruptive, by employing a control (no-prime) condition in addition to a related-prime condition and an unrelated-prime condition. According to the activation hypothesis, which predicts a facilitative effect of musically related chords, responses are expected to be faster in the related-prime condition than in the control condition. In contrast, according to the schema hypothesis, which supposes a disruptive effect of musically unrelated chords, responses are expected to be slower in the unrelated-prime condition than in the control condition. No facilitative effect was found in the related-prime condition, whereas a marked disruptive effect was found in the unrelated-prime condition. The disruptive effect was more pronounced in the major-chord condition than in the minor-chord condition, and more salient at an interonset interval of 1 s than at 3 s or 7 s. These results are interpreted in terms of the schema hypothesis.

Early ERP responses to own names while gaming

Calling and being called by ones own name play essential roles in our social life. In the study reported here, we investigated the possibility that own as opposed to other names would be automatically detected by mechanisms utilizing some initial acoustic indications. To this end, we examined early event-related potential responses (up to 400-ms latency) to ones own and other names while playing a video game with no sound effects. To test possible effects of emotion, we used name stimuli uttered by a female speaker in 3 emotional tones (angry, love, and neutral) and recruited 10 young male participants. We observed the modulation of the P1, P2, and N2 waves caused by the name-property manipulation (i.e., own VS. other names). The name-property effects did not significantly interact with the emotional tone factor. These automatic modulations may reflect early detection processes concerning signals of potential importance at multiple, perhaps initially coarse but later less coarse, processing stages. The paradigms using own and other names may provide unique ways both to investigate mechanisms by which personally/socially significant signals are processed and to assess neural circuitry in various neurological or developmental populations.