Ecological Information Is a Perceptual Mapping That Tracks Evolutionary Fitness

Interface theory in cartoon form. Thanks to Louise
Barrett for reminding me this exists :)

In my last post I was thinking out loud about some ecological lines of attack on interface theory (Hoffman et al, 2015). The first line of attack (Hoffman et al mischaracterise Gibson) fell over eventually; they don't quite go at it right, but using ecological information does fit their definition of a naive realist perceptual strategy ( 'a perceptual strategy for which X [perceptual experience] ⊂ W [the world] and P [the perceptual mapping] is an isomorphism on this subset that preserves all structures on W'; pg 1483). The second line of attack (everything they say about veridicality vs fitness applies only to inferential, constructivist theories of perception and Gibson's not playing that game) is true but not that interesting or convincing to anyone with established views.

Thanks to chats on Twitter (thanks Greg!) and applying the basic move of 'those aren't working but IT is still weird, what's next?', my new line of attack relates to a result from their simulations.

Does Interface Theory Have Consequences for the Ecological Approach?

I've been working on a commentary about interface theory (Hoffman, Singh & Prakash, 2015) which I have previously blogged about here. I'm still interested because it is, in part, a fairly direct shot at the ecological approach and I'm always keen to break those if I can. My piece stalled out, though, so I thought I'd spend some time here thinking out loud about the argument that stalled and another critique that came up as I re-read the paper.

To unbury the lede I just finished writing: the primary thing Hoffman et al get wrong about Gibson is that they think he wanted his theory to produce veridical perceptions, not simply adaptive ones. Gibson actually wanted adaptive perceptions, but found a way in which they were also veridical. This emphasis matters; Gibson does not stand or fall on issues of veridicality. In addition, every one of Hoffman et al's big swings apply only to inferential, constructivist theories of perception; Gibson is immune on these grounds as well. All Hoffman et al have done is redraw the terrain inferential theories have to traverse, and it will be interesting to see if anyone takes the bait. But the major argument simply remains, is perception inferential or ecological, and may the best data set win.

The Interface Theory of Perception - The View from Ecological Psychology

Psychonomic Bulletin & Review has released, with much fanfare and a hashtag, an article called 'The Interface Theory of Perception' (Hoffman, Singh & Prakash, 2015). From the website description:

In a nutshell, interface theory postulates that our perception operates like a species-specific desktop: We perceive the world in representations that do not represent the “truth” about the world as it actually is, but that are useful “icons” which represent fitness-relevant information about the world. To illustrate, imagine a world in which red and green berries are nutritious but blue and yellow berries make you sick. Will your perceptual system differentiate red from green and blue from yellow? According to interface theory, the answer is no—the organism will have evolved to differentiate between only two colors, namely gred and byellue.

The meat of the paper is a series of evolutionary simulations that pit various perceptual strategies against one another. These strategies vary in how veridical they are, and the key result is that interface strategies, in which perception codes things in a way that bears no resemblance to the world, wins every time. We do not perceive the world as it really is. 

This seems to go against people like Gibson, who argue that perception is of a real world and real properties of things, like affordances. These simulations seem to show that 'realist' perceptual strategies are evolutionarily unsustainable. 

The devil, as always, is in the details, and having read the paper I am now pretty sure that Gibson is quite safe, and that information offers a path out of the weirdness Hoffman conjures.