Zygmunt Pizlo: “I am an “expert” on 3D shape perception, so I will confine my comments about veridicality to shape. Unlike Hoffman et al., I do not have the temerity required to discuss veridicality in vision in general, as well as in smell, taste, touch and hearing in such varied species as humans, bees, and spiders.”
“… Any contemporary use of a Motor Theory of Perception, and this includes Hoffman et al.’s explanation of 3D shape perception, can be viewed as a legacy of psychology’s Dark Age called “Radical Behaviorism”. This is precisely what Hoffman et al. are offering us. As for me, “no, thank you very much.”
Zygmunt Pizlo’s paper does a wonderfully concise job of bringing Hoffman’s “veridicality” challenge back down to Earth and our three dimensional world. This paper was 1200 words long and I whittled to 500 some odd. Please visit the complete article for all the details.
Philosophizing cannot substitute for experimentation: comment on Hoffman, Singh & Prakash (2014)
- Zygmunt Pizlo, September 18, 2015
volume 22, pages 1546–1547 (2015)
Abstract
The perception of a 3D shape must be excluded from Hoffman et al.’s “interface theory” primarily because shape is characterized by its symmetries. When these symmetries are used as a priori constraints, 3D shapes are always recovered from 2D retinal images veridically.
These facts make it clear that 3D shape perception is completely different from, as well as more important than, all other perceptions because the veridicality of our perception of 3D shapes (and 3D scenes) accounts for our successful adaptation to the natural environment.
… when we talk about veridical 3D perception, we are referring to our natural visual space, that is, a space with natural, symmetrical objects residing, as they naturally do, on a common ground because of gravity.
The concept of an “empty” visual space, used in laboratories, that contains only a few isolated points of light in total darkness, or a few objects floating in the air, no matter how attractive mathematically, is actually empty from an empirical, as well as from a computational, point of view. …