Benham's Top

About

<This page in English is under construction.>

On RIKEN Open Day, April 22, 2017, Neuroinformatics Japan Center demonstrated a Hands-on event, " Find your subjective color by spinning a top". Materials related to the demonstration has been released at Tutorial Content page of this portal. It includes questionnaire, summary on the individual difference of subjective color seeing, how to make a top and a review article on the subjective color. This photo is a wooden benham's Top sold by THE TOYCRAFTER.  

Creator of this page:  Neuroinformatics Japan Center, RIKEN BSI

  Articles: Yoko Yamaguchi; Linked contents Itsuko Ishii, Yoshihiro Okumura, Yoko Morii, Sawako Suenaga, Ayumi Honda, Miyabi Ogawa, Jonathan Lai, Sutthinan Anantarattachai, Munenori Takaku 

May 15, 2017

What is Benham's Top?

Benham's Top is a top with a disk of black and white pattern, while it's spinning causes color perception. The color percieved by rotating a black and white pattern is a kind of illusion and is called "subjective color". This phenomena was discovered by a psychologist, Gustaf Theodor Fechner (1801 - 1887), a founder of psychophysics. Benham is a name of the toymaker who made the phenomena popular through the top.  

INCF Japan Node Tutorial Contents: Demo Video of spinning a Benham's Top
         

Figure 1  Benham's top movie (left) and the pattern printed on its disk (right). The same pattern is downloadable at Visiome Platform.

If you feel uncomfortable by watching the movie, please stop watching immediately. Please do not watch the movie for a long time near the screen.  

 

Individual difference in subjective color appearance

It is unknown why there is  an individual differences in the perception of subjective colors. We conducted a questionnaire on the color perception of Benham's top on RIKEN Open Day, April 22, 2017. We hereby report the questionnaire method and the result summary as below.


Method of questionnaire

Hand-made top was prepared by using a CD disk and a marble. The black and white pattern was printed  on the disk. The disk pattern used in the questionnaire consists of four types of stripes, each of which has an interval of 45 degrees as shown in the left picture. The four types of stripes result in perception of four different color bands. These bands are called band 1, band 2, band 3 and band 4 in the order from inside to outside of the disk. The questionnaire sheet uses the Munsell color system. Each participants was asked to select the closest color they perceived on each bands from the Munsell color system. All questionnaires were conducted in Japanese.

 

                      

 Questionnaire sheet I (in Japanese only)           How to answer the questionnaire (in Japanese only)

 


 

Results (in Japanese only)

The total number of answers was 301. By removing incomplete answers, 280 answers were used for the summary below.

 

 Figure 2  Hue distribution of perceived colors at each band         Figure 3  Comparison among three groups with different ages.

 

The number of answers of black/white was obviously very few. At each band, one peak or a few peaks with a broad hue distribution were observed. Interestingly, different age groups had diferent hue peaks. Further summary is availble below.

  Material 1: Summary of questionnaires  <PDF>

 

How to make a top

How to make the top is available in Japanese below. It is to be added  in English soon.

Material 2: Methods in japanese<PDF>      

Movie of hand-made top

INCF Japan Node Tutorial Contents: Demo video of spinning a handmade top

If you feel uncomfortable by seeing the movie, please stop to see. Do not see the movie for a long time at close.  

 

Mechanisms of seeing subjective color

Review of mechanism of subjective color in English is to be added soon.

Material 3: Mechanism of seeing subjectibe color in Japanese  <PDF>

 

References

 

北岡明佳 北岡明佳の錯視のページ  色の錯視(2016) 主観色   (2012)

 

小松英彦 色選択性細胞  脳科学辞典 DOI10.14931/bsd.6413 (2015)

Visiome Platform           URL https://visiome.neuroinf.jp/

 

How to cite

本ページおよびリンクされている各ビデオ・資料の引用は下記の通りです。

本ページ)

理化学研究所 脳科学総合研究センター 神経情報基盤センター. "INCF日本ノードチュートリアルコンテンツ:ベンハムの独楽", 2017.
https://www.neuroinf.jp/tutorial/benham/

 

各ビデオ・資料)データの詳細のページにある作成者氏名、アイテムタイトル、発行者、年度の順で引用して下さい。

動画1:ベンハムの独楽のムービー)

Itsuko ISHII. "INCF Japan Node Tutorial Contents: Demo Video of spinning a Benham's Top". Neuroinformatics Japan Center, RIKEN Brain Science Institute, 2017. https://www.neuroinf.jp/modules/xoonips/detail.php?id=tutorial.benham.demo1

動画2:手作り独楽の動画)

Itsuko ISHII. "INCF Japan Node Tutorial Contents: Demo video of spinning a handmade top". Neuroinformatics Japan Center, RIKEN Brain Science Institute, 2017. https://www.neuroinf.jp/modules/xoonips/detail.php?id=tutorial.benham.demo2

資料1:アンケート結果のまとめ)

Jonathan LAI, Sutthinan ANANTARATTANACHAI, Munenori TAKAKU, Yoko YAMAGUCHI. "INCF Japan Node Tutorial Contents: Summary of Questionnaires on Benham's Top". Neuroinformatics Japan Center, RIKEN Brain Science Institute, 2017. https://www.neuroinf.jp/modules/xoonips/detail.php?id=tutorial.benham.questionnaire_sum

資料2:独楽の作り方)

Itsuko ISHII. "INCF Japan Node Tutorial Contents: How to make a top (Ja)". Neuroinformatics Japan Center, RIKEN Brain Science Institute, 2017. https://www.neuroinf.jp/modules/xoonips/detail.php?id=tutorial.benham.howtoja

資料3:色を見るしくみ)

Yoko YAMAGUCHI. "INCF Japan Node Tutorial Contents: Mechanisms of Seeing Subjective Color (J)". Neuroinformatics Japan Center, RIKEN Brain Science Institute, 2017. https://www.neuroinf.jp/modules/xoonips/detail.php?id=tutorial.benham.mechanism

 

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