The Relationship Between Stimulation and Stimulus Information (Gibson, 1979, Chapter 4)

The first three chapters describe the world to be perceived, at the ecological scale. This chapter opens the section on how we visually perceive that world - via information. Remember, a key part of the ecological analysis is doing things in this order (see the Introduction). 

The work of the next few chapters is to lay out a theory of ecological optics. Lots of science studies light, but as with the physical world/environment distinction, Gibson will insist on distinguishing between the physics of light and the ecology of it; only the latter will be relevant to a theory of perception. 

Sabrina also blogged this chapter here. 

The Meaningful Environment (Gibson, 1979, Chapter 3)

In Chapter 1, Gibson identified the animal and it's environment as the two mutually defining parts of an ecological system. In Chapter 2, he developed a vocabulary for describing an environment (as opposed to the physical world). Now, in Chapter 3, he will use that vocabulary to identify that the environment of an animal is meaningful, literally full of meaning, and this will mean that meaning is there to be discovered, rather than constructed (as in every theory of perception so far). 

Sabrina also blogged this chapter here. 

Medium, Substances, Surfaces (Gibson, 1979, Chapter 2)

In this chapter, Gibson continues to lay out the rules of the environment (vs the physical world). In physics, there are objects in spaces, but this simply does not work as the basis of perception (see the chapters about Helmholtz and the limits of unconscious inference in the Turvey book). Instead, environments are made of medium, substances, and surfaces, and this chapter defines these at the ecological scale.

This chapter introduces a lot of vocabulary for talking about the environment: I have reviewed some of it, but see the chapter for the full set because it is going to be needed as we described the environment to be perceived. 

Note: Sabrina also blogged this chapter here.

The Animal and the Environment (Gibson, 1979, Chapter 1)

Gibson's first chapter introduces his notion of the environment. This is a distinct level of description from the world according to physics, even though everything in it is still made of physical stuff. The environment is the ecologically-scaled surroundings to an organism, and Gibson lays out some of the key differences between this and the physical world here. Why? Because perceiving is going to be of the environment, and not of the physical world, and as we progress this is what the word 'environment' will mean.

Note: Sabrina also blogged this chapter here.

Introductions in the 2014 Edition (Gibson, 1979 Reading Group)

The 2014 reprint of Gibson (1979) includes the original Preface and Introduction, as well as an Introduction to the Classic Edition by William H Mace. A few things come up in Gibson's sections that I thought were cool, and worth documenting as part of the reading group. 

Mace's Introduction does some nice work reviewing Gibson's intellectual development over the course of his career and exemplified by his three books. He points to how the ecological approach has grown and connected to other fields in the years since Gibson's death, and talks about how the 1979 book was received (a mixed bag, to say the least!). It's a good read, but it doesn't have much new content in it so for this reading group I'll just focus on the bits Gibson says that set things up nicely. 

Reading Group - Gibson (1979) The Ecological Approach to Visual Perception

Rob, Marianne, and I had so much fun with the Turvey (2019) reading group that we decided to keep going, and we decided to return to the source - Gibson's 1979 book. Buckle up, this should be fun!

We'll be using the 2014 edition, so all page numbers will refer to that (I have the feeling I will be directly quoting the eminently quotable Gibson a lot more than I did with Turvey!). I will use this page to link to my post, and the video and podcast links for our group discussions, for each chapter.

Gibson (1979) The Ecological Approach to Visual Perception

Introductions in the 2014 edition

Part I: The Environment to be Perceived

Chapter 1: The Animal and the Environment

Chapter 2: Medium, Substances, Surfaces

    Chapters 1 & 2: Video || Podcast

Chapter 3: The Meaningful Environment  

Part II: The Information for Visual Perception

Chapter 4: The Relationship Between Stimulation and Stimulus Information  

    Chapters 3 & 4: Video || Podcast

Chapter 5: The Ambient Optic Array  

Chapter 6: Events and the Information for Perceiving Events  

    Chapters 5 & 6: Video || Podcast

Chapter 7: The Optical Information for Self-Perception  

Chapter 8: The Theory of Affordances  

    Chapters 7 & 8: Video || Podcast

Part III: Visual Perception

Chapter 9: Experimental Evidence for Direct Perception: Persisting Layout  

Chapter 10: Experiments on the Perception of Motion in the World and Movement of the Self  

    Chapters 9 & 10: Video || Podcast

Chapter 11: The Discovery of the Occluding Edge and Its Implications for Perception  

Chapter 12: Looking with the Head and Eyes  

    Chapters 11 & 12: Video || Podcast

Chapter 13: Locomotion and Manipulation  

Chapter 14: The Theory of Information Pickup and Its Consequences  

    Chapters 13 & 14: Video || Podcast

Part IV: Depiction

Chapter 15: Pictures and Visual Awareness  

Chapter 16: Motion Pictures and Visual Awareness  

    Chapters 15 & 16: Video || Podcast

Lecture 26: Strong Anticipation and Direct Perception (Turvey, 2019, Lectures on Perception)

In this final chapter, Turvey lays out the basics of the ecological approach to coordinating action with respect to the future. This is actually a key part of behaviour - we reach for things we know are graspable before grasping them, we move to intercept or avoid things before they are anywhere near us, and so on. The question is how do we do this.

The ecological approach cannot, of course, use prediction to solve this problem. Prediction entails representation, making educated guesses about what is coming up based on loans of intelligence we cannot ever pay off. The whole point of this book has been to lay out the argument that a) this approach is doomed to fail but that b) the ecological approach, grounded in laws, is different enough in kind to be a viable option. 

Coordinating with things not in the immediate present is therefore going to rely on lawful informational coupling to dynamical events, with several interesting consequences.