視線計測によって、アーティストの意図を読み解く

Michelangelo Merisi da Caravaggioは17世紀の最も影響力のある画家の1人であり、特に照明効果に特徴があるので有名です。

Caravaggioは、光学的研究が盛んで、画家の作品が特定の場所に展示されるように作成された時代に活動していました。

イタリアScienza Nuovaの研究者は、Caravaggioが画像をどのように認識し、芸術を創作する際にとりまく環境が、来場者の視覚運動にどのように影響するか、の仮説を検証するためにアイトラッキングを使用しました。

研究は、芸術を元の環境から移動すると、意図された視聴者体験が減少することを明らかにした。

これらの結果は、芸術作品が美術館でどのように展示されるのが良いのか、また来場者にとって最高の経験を得るためには、芸術作品をどのように見ればいいのか、といった観点から役立ちました。

Tools and methods

この調査では、ウェアラブル型アイトラッカーTobii Pro Glasses 2をデータ収集に使用して、被験者の自然な視線の動きを促進しました。
今回芸術界でアイトラッキング調査が初めて行われたのです。

Pro Glasses Analyzerソフトにより、視線の動きと視覚刺激を簡単にオーバーラップさせることができました。

調査は2部に構成され、2つの異なる場所で、被験者がCaravaggioの絵を見てどこに注意を払っているのか、というデータを収集しました。

第1部では、ナポリのPio Monte della Misericordia教会で3日間にわたって行われました。Caravaggioの絵画であるSette Opere di Misericordiaは、そこに元の状態で保存されています。

第2部では、ナポリのCapodimonte博物館で行われました。これはCaravaggioのLa Flellellazione di Cristoという作品が展示されている場所です。

研究者は、教会と博物館の訪問者から被験者を無作為に選びました。

キャリブレーション後、Pro Glasses 2を3分間装着してもらい、自然にその場所を歩いて頂きました。 

視線データ、凝視までの時間、AOIデータ、視線への訪問回数などの分析をするためにアイトラッキングは活用されます。

Tobii Pro Glasses 2 wearable ye tracker used in a painting viewing study in Italy

Results

In the first phase, the visual pathway of the subjects was defined. It was discovered that each participant focused their attention on the same area of interest. In fact, the aggregated data allowed researchers to identify five areas of interest on the basis of the fixation count. These were visualized by the Pro Glasses Analyzer in a heatmap.

The time to first fixation, which corresponded to the precise moment when the visitor actively observed each portion of the painting, demonstrated not only when the gaze was resting on each of the scenes of the composition but also when the visitor started the cognitive process of understanding.

The Pro Glasses Analyzer's gazeplot visualizations confirmed that the visual pathway of the participants was repetitive, and two recurring visual patterns were found.

In the second phase of the study, it was not possible to find a common pathway among the 22 participants in the experiment. In fact, the researchers indentified 20 different patterns. To compare the variability of pathways in the two different scenes, a Pathway.Variability Index (PVI) was defined:

PVI = number of distinct pathways / number of subjects.

This PVI tends to be 0 when there are very few distinct pathways (i.e. low variability with several subjects using the same pathway), and it tends to be 1 when the number of distinct pathways increases with the number of the subjects (i.e. high variability with each subject performing a different pathway). A PVI of 0.35 was obtained in the first scenario, and 0.90 was the PVI in the second one - much higher than the previous case.

Tobii Pro Glasses 2 wearable ye tracker used in a painting viewing study in Italy

Conclusions

There is growing evidence that Caravaggio was aware of the phenomenon of the perception of images since optical studies were popular in the 16th century. It is possible that he used this knowledge to direct the construction of his paintings so that his methods still control how his work is consumed by viewers after several centuries have past.

Eye tracking allowed the researchers to validate this hypothesis by observing the visual pathway of the visitors to Pio Monte della Misericordia, where Caravaggio's painting, Sette Opere di Misericordia, is preserved in original condition. Data collected from a group of 40 visitors showed that people follow a consistent pattern when observing this work of art.

In contrast, there was no common pattern found among the visitors at the Capodimonte Museum for Caravaggio's painting, La Flagellazione di Cristo, which was on exhibit in different physical conditions from those originally intended when the work was created. Although the areas of interest were shared among most visitors, the order (visual pathway) was different for each of the participants.

Background

Since ancient times, we have wondered how the human brain acquires and processes images from the outside world. Cognitive psychology explains the phenomenon through embodied simulation: the ability to build a representation of the outside world to which our visual experiences are related. The act of viewing art is so complex that the cognitive disciplines have begun to use eye tracking to observe both ocular and brain behavior.

The goal of this study is to identify the formal elements (line, shape, form, tone, texture, pattern, color, and composition) that guide the viewer through the works of the painter in order to apply the techniques of Michelangelo Merisi da Caravaggio to other visual pieces. The intent is to increase the effectiveness of images in many fields, improve the museum experience, and increase the appreciation of artwork.

The interaction of art and the brain has been the focus of numerous studies, but this is the first time that the study of this process is being used to improve the guest-fulfillment experience.