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Against better knowledge: The magical force of amodal volume completion.

Ekroll V, Sayim B, Wagemans J - Iperception (2013)

Bottom Line: In a popular magic routine known as "multiplying billiard balls", magicians fool their audience by using an empty shell that the audience believes to be a complete ball.Here, we present some observations suggesting that the spectators do not merely entertain the intellectual belief that the balls are all solid, but rather automatically and immediately perceive them as such.Our observations demonstrate the surprising potency and genuinely perceptual origin of amodal volume completion.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102 - box 3711, 3000 Leuven, Belgium; e-mail: vebjorn.ekroll@ppw.kuleuven.be.

ABSTRACT
In a popular magic routine known as "multiplying billiard balls", magicians fool their audience by using an empty shell that the audience believes to be a complete ball. Here, we present some observations suggesting that the spectators do not merely entertain the intellectual belief that the balls are all solid, but rather automatically and immediately perceive them as such. Our observations demonstrate the surprising potency and genuinely perceptual origin of amodal volume completion.

No MeSH data available.


Schematic illustration of the basic effect. A semi-spherical shell is put on the table and viewed directly from above. As the shell is lifted up from the table towards the eye of the observer (a)–(d), it is perceived to morph gradually into a complete ball (e)–(h).
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Figure 2: Schematic illustration of the basic effect. A semi-spherical shell is put on the table and viewed directly from above. As the shell is lifted up from the table towards the eye of the observer (a)–(d), it is perceived to morph gradually into a complete ball (e)–(h).

Mentions: We believe that the key to understanding the impressive powerfulness and robustness of this magical routine is this: Amodal volume completion (Tse, 1999; van Lier, 1999; van Lier & Wagemans, 1999) must be understood as a genuinely perceptual phenomenon (Gerbino & Zabai, 2003; Kanizsa, 1970, 1985; Kanizsa & Gerbino, 1982; Michotte, Thinès, & Crabbé, 1964) in the sense that it is automatic and cognitively impenetrable (Pylyshyn, 1999). Viewed from this perspective, the spectators do not merely entertain the intellectual belief that the semi-spherical shell is a solid ball, but rather automatically and immediately perceive it as such because that is what their visual systems tell them to be the case. Here, we describe how a simple and intriguing observation supporting this explanation can be made. Put a semi-spherical shell on a table and view it directly from above, as illustrated in Figure 2. In this situation, the shell is perceived as a semi-sphere. If you hold it slightly above the table, however, it looks like a full sphere. These observations can be made with the same result irrespective of whether the semi-spherical shell is viewed monocularly or binocularly. Note, however, that if the semi-spherical shell is photographed rather than viewed directly, it looks like a full sphere in both cases. Together, these observations suggest (1) that the visual system prefers the full sphere interpretation by default and (2) that this default can be overridden by cues signalling (a) that the semi-spherical shell is so close to the plane of the table that there is not enough free space to accommodate a full sphere and (b) that the surface of the table is indeed completely planar.


Against better knowledge: The magical force of amodal volume completion.

Ekroll V, Sayim B, Wagemans J - Iperception (2013)

Schematic illustration of the basic effect. A semi-spherical shell is put on the table and viewed directly from above. As the shell is lifted up from the table towards the eye of the observer (a)–(d), it is perceived to morph gradually into a complete ball (e)–(h).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129385&req=5

Figure 2: Schematic illustration of the basic effect. A semi-spherical shell is put on the table and viewed directly from above. As the shell is lifted up from the table towards the eye of the observer (a)–(d), it is perceived to morph gradually into a complete ball (e)–(h).
Mentions: We believe that the key to understanding the impressive powerfulness and robustness of this magical routine is this: Amodal volume completion (Tse, 1999; van Lier, 1999; van Lier & Wagemans, 1999) must be understood as a genuinely perceptual phenomenon (Gerbino & Zabai, 2003; Kanizsa, 1970, 1985; Kanizsa & Gerbino, 1982; Michotte, Thinès, & Crabbé, 1964) in the sense that it is automatic and cognitively impenetrable (Pylyshyn, 1999). Viewed from this perspective, the spectators do not merely entertain the intellectual belief that the semi-spherical shell is a solid ball, but rather automatically and immediately perceive it as such because that is what their visual systems tell them to be the case. Here, we describe how a simple and intriguing observation supporting this explanation can be made. Put a semi-spherical shell on a table and view it directly from above, as illustrated in Figure 2. In this situation, the shell is perceived as a semi-sphere. If you hold it slightly above the table, however, it looks like a full sphere. These observations can be made with the same result irrespective of whether the semi-spherical shell is viewed monocularly or binocularly. Note, however, that if the semi-spherical shell is photographed rather than viewed directly, it looks like a full sphere in both cases. Together, these observations suggest (1) that the visual system prefers the full sphere interpretation by default and (2) that this default can be overridden by cues signalling (a) that the semi-spherical shell is so close to the plane of the table that there is not enough free space to accommodate a full sphere and (b) that the surface of the table is indeed completely planar.

Bottom Line: In a popular magic routine known as "multiplying billiard balls", magicians fool their audience by using an empty shell that the audience believes to be a complete ball.Here, we present some observations suggesting that the spectators do not merely entertain the intellectual belief that the balls are all solid, but rather automatically and immediately perceive them as such.Our observations demonstrate the surprising potency and genuinely perceptual origin of amodal volume completion.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102 - box 3711, 3000 Leuven, Belgium; e-mail: vebjorn.ekroll@ppw.kuleuven.be.

ABSTRACT
In a popular magic routine known as "multiplying billiard balls", magicians fool their audience by using an empty shell that the audience believes to be a complete ball. Here, we present some observations suggesting that the spectators do not merely entertain the intellectual belief that the balls are all solid, but rather automatically and immediately perceive them as such. Our observations demonstrate the surprising potency and genuinely perceptual origin of amodal volume completion.

No MeSH data available.