One of the most common comments about ecological psychology is that it's hard to imagine how it could apply to things like language. The sense is that language is a completely different kind of beast than perception-action and that it requires a completely different theoretical account (cognitive psychology). Andrew and I disagree. In this post I outline the similarities and differences between language and other types of perceptual information. The main idea is that language is indeed the same type of thing as perception-action, but there are key differences between them in the relationship between the information and what it means. These differences permit language to be flexible according to context, culture, and goals; to be expandable according to changing needs; and to be portable, allowing us to access information about things that are not currently in the environment. These properties make language special, but not magical.
Events in the world are defined in terms of their underlying dynamics. For example, two instances of a bouncing ball are instances of the same type of event - a bouncing-ball-event - because the dynamical equations of motion are the same in both cases. The two instances might be different in their parameters (e.g. the initial height of the ball) but they are still examples of the same event in the world.
Events in the world create information. The light reflecting off a bouncing ball is structured according to the laws of ecological optics by the specific motion of that ball. This structure (optic flow) is specific to the event in question and any organism that detects this information can therefore directly perceive the event in the world. The meaning of the information in this case is the dynamics of the event in the world and this is the meaning that the organism must learn. If the organism can use this information to successfully control it's behaviour, we take this as evidence that the organism has access to this meaning.
Speech is a type of event (well, probably a series of nested events, but I'll get to this later). The act of speaking structures the acoustic array according to the laws of ecological acoustics. This structure is specific to the speech event, and any organism that detects this structure can therefore directly perceive the speech event. But in this case, the meaning of the information is not the dynamics of the articulation of the word. The meaning the organism must learn is the conventional meaning of the word that was spoken and, if the organism acts in a manner consistent with that conventional meaning, this again is evidence for access to that meaning.
From a first person perspective, both cases require learning the meaning of information. I argue that the mechanism of learning this meaning is identical for both types of event.
If, for analysis purposes, we adopt a third person perspective it is possible to see an important difference between speech events and events such as bouncing balls. The difference is in the relationship between the information and what that information means. For the bouncing ball, the fact that the optic flow pattern means 'bouncing ball' is underwritten by the lawful process by which the ball's motion was projected into the optic array, and the form of the information therefore relates to the underlying event. For the speech event, the fact that the acoustic array pattern means, for example, 'Hello' is not underwitten by a lawful process, and
...there is no intrinsic similarity between the sounds of most words and their referents: the form of the word dog gives us no hints about the kind of thing to which it refers. And nothing in the similarity of the forms of dig and dog conveys a similarity in meaning.
Smith & Gasser, 2005, p. 22
Language as an information medium
For the sake of clarity, I will reserve the term perception to refer to the apprehension of structure in an energy array when the meaning of this information is underwritten by a specification relationship between the information and the world. Using this definition, hearing the word "dog" is not an act of perception. This is because hearing a spoken word involves the apprehension of structure in an energy array when the meaning of this information is underwritten by a conventional relationship between the information and the world. When I use the term perceptual information, I mean information whose meaning is underwritten by a specification relationship. Auditory information is about sounds. Visual information is about visual properties of the environment. In contrast, linguistic information (in whatever modality it is conveyed) is about the conventional meanings of linguistic events, which might refer to sounds, sights, ideas, etc.
Because the auditory events of spoken language are about the conventional meanings of linguistic events rather than the physical act of speech articulation, it may be helpful to think of language as its own medium. The medium of language permits the flow of linguistic information through the modalities of sound (speech), vision (writing, sign language), and touch (Braille).
This difference is obviously important and the consequences of it have been noted by many linguists and psychologists. For one thing, humans are uniquely adept at using linguistic information. Learning the meaning of a linguistic event is more difficult than learning the meaning of perceptual information. I can say the word "dog" whether or not there is an actual dog nearby, but the sound of a dog barking is usually going to mean that there is a dog within earshot. Humans have some adaptations that help them with this problem. We are good at establishing joint attention to something in the environment. We are also incredibly motivated to communicate with one another, which means that we're willing to persevere with this difficult learning problem. The process of learning the meaning of linguistic information will be an important part of a research programme on ecological approaches to language. That said, the task analysis that I will undertake in the next post will focus on proficient language users rather than on beginners.
To summarise, then: the route from language to it's meaning is not underwritten by laws, the way the route from perceptual information to it's meaning is. But, critically, from the first person perspective of the organism, there is no difference in what it is interacting with, and I argue that the organism will therefore apply the same tools to both problems. The different outcomes reflect the differences in the routes to meaning, and not fundamental differences within the organism.
In the next post I will consider the types of tasks for which linguistic information might be useful. An actual research programme would select one specific task from one of these types, but I want to begin by thinking broadly about when and how linguistic information guides behaviour. I will also introduce the idea of perceptual-linguistic systems, which will be central to understanding how the meaning of a linguistic event is understood. Finally, I will discuss why this approach to language is explicitly non-representational.
Smith, L. & Gasser, M. (2005). The development of embodied cognition: Six lessons from babies. Artificial Life, 11 (1), 13-30.