From this point it became clear that we could use a set of properties to characterise information types. And, looking across this set of properties, it became clear that there is more than just perceptual and linguistic information. I use the term "information" to refer to any structure in an energy array that precipitates behavior in an organism. The taxonomy below provides a common language for talking about all types of information - from symbols to reflexes.
I first walk through the major dimensions, as I see them, that define differences between information types. I will then apply this framework to perceptual and linguistic information and suggest how these dimensions might also be used to capture other types of information (e.g., reflexes). Finally, I add some more speculative dimensions and say a bit about how I think this taxonomy might be useful.
*********************************************************************Each of the properties in my initial definition of perceptual information represents an endpoint of a dimension. It will now be useful to consider the opposite poles of these dimensions. I've ordered the poles 1 and 2 within each dimension to reflect my intuition about their simplicity - more "basic" or "simpler" characteristics are listed as "Pole 1" and more "complex" characteristics are listed as "Pole 2". I've also added a dimension (Learning) to the original list.
Dimension: Detection
Pole 1 - The organism does not have to learn to detect the structure - it can detect the structure without prior learning.
Pole 2- The organism must learn to detect invariant structure in energy arrays.
Dimension: Specificity
Pole 1 - The structure in the array is specific* to an event in the world. For a given ecological niche, this structure (in light, sound, whatever) is present only when a given event or property of the world is present.
Pole 2 - The structure in the array is not specific to a particular event or property.
*This dimension captures the relationship between the world and structure in energy arrays. For Pole 1 this relationship is 1:1; for Pole 2 this relationship is many:1. Most people refer to Pole 1 as a specification relationship, but there is some unfortunate fuzziness in the way the term "specification" is used. Ecological laws make it so that any invariants in an energy array will specify something - that is, the structure will be in a 1:1 relationship with some property or event in the world (this is why the variable can be invariant in the first place). If this is the case, then it is deeply confusing to talk about whether organisms can use non-specifying variables to control action. What we really mean is "can organisms use variables that don't specify the property or event of the world that is relevant for a particular task?" So called non-specifying variables specify something - just not the thing that is most directly related to the task at hand.
This, then, might be a redundant dimension. The important work might be done in the next dimension - Aboutness. I don't know whether there are cases where the information would occupy Pole 2. Because of this uncertainty, I'd like to keep it in for now, and get rid of it if I'm convinced it's not doing any work.
Dimension: Aboutness
Pole 1 - The meaning of the structure in the array is about* the event or property specified by the structure.
Pole 2 - The meaning of the structure is about something else - not about the property specified by the structure.
*Aboutness is similar to the specification versus convention distinction I wrote about in the language posts. Meaning is defined in terms of an organism's ability to take appropriate action as a consequence of detecting information. When the action is related to the event in the world that caused the structure in the energy array (e.g., we duck upon hearing a loud noise) then the information is defined in terms of Pole 1. When the action is not related to the event in the world that caused the structure (e.g., when we duck upon hearing the exclamation "Duck!"), then this information is defined in terms of Pole 2.
The event in the world that caused the structure of the spoken word "Duck" is the control of the speaker's vocal tract and voice to create the phonemes comprising the word. As listeners, we don't care about this event. We care about the conventional meaning of the event, which is that if you don't lower your head it's going to be hit by something.
Dimension: Learning
Pole 1 - The organism does not have to learn how to use the information.
Pole 2 - The organism must learn how to coordinate its actions with respect to this structure.
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With terminology in place, we can see that perceptual information falls at Pole 2 for the Detection and Learning dimensions. And, it falls at Pole 1 for the Specificity and Aboutness dimensions. In contrast, linguistic information falls at Pole 2 for Detection, Aboutness, and Learning. It falls at Pole 1 for Specificity (because the structure in the energy array caused by saying a word is specific to the event in the world that caused it).
I said that this terminology opened the door to thinking about other types of information. Consider reflexes. Reflexes are precipitated by structure in an energy array (e.g., the startle reflex is precipitated by a loud noise). Organisms don't have to learn to detect this structure and they don't have to learn to coordinate their actions with respect to it. Thus, reflex information falls at Pole 1 along all four dimensions. Instinct information may be similar.
I would like to look at non-human animal behavior to see what other combinations are possible. For instance, can we identify cases where organisms must learn to detect structural invariants but don't need to learn how to coordinate their actions with respect to them (i.e., certain actions are "hard-wired" in the presence of the right information)? Perhaps instinct information falls into this category? This type of behavior would fall at Pole 2 on the Detection dimension and Pole 1 for Aboutness, Specificity, and Learning.
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Another two dimensions may also be relevant to this taxonomy, but my ideas about them are less well-developed than for the other dimensions. These dimensions are Inherentness and Continuity.
Dimension: Inherentness
Pole 1 - The structure in the array is inherently meaningful to the organism in that it causes some feeling (e.g., pain, pleasure) in the organism that is not related to any learned fact about the structure.
Pole 2 - The structure in the array is not inherently meaningful
When I look at a very bright light, it is inherently unpleasant. When I hear a loud noise, it is inherently unpleasant. Touch can be either pleasant or unpleasant depending on how it's done (and depending on the context, which makes this dependent on learned meaning as well). In contrast, some information has no inherent meaning. For babies in EJ Gibson's visual cliff experiment, the visual information that specified a surface discontinuity had no inherent meaning; babies who weren't crawling were not afraid of the drop because they did not know what the visual information meant.
Inherentness has some things in common with the Learning dimension, but I think it is rightfully distinct. There is a phenomenology implied in the Inherentness dimension that is not necessary for the Learning dimension.
Dimension: Continuity
Pole 1 - The structure in the energy array precipitates an action in the organism, but this action is not coupled to the information over time
Pole 2 - The structure in the energy array precipitates an action and the organism couples its actions to this information over time
This dimension captures whether information is used in the continuous control of action or whether it acts more like a cue. I want to mention this because cues often get the short shrift in ecological psychology, although they clearly matter. Consider the redness of an apple. This structure in the visual array may cue subsequent action (i.e., I might reach for the apple because the redness tells me that it's ripe), but I do not use the redness in the continuous control of action. Thus, the continuity dimension may allow us to sub-divide some types of information - perceptual information like the redness of the apple versus perceptual information for the catchability of a fly ball. The continuity dimension might be an additional way to distinguish between instincts and reflexes (instincts fall along Pole 2 and reflexes fall along Pole 1). Because ecological psychology has focused on information for action, we don't have a very good, non-cognitive way to talk about cues right now and this needs to change.
*******************************************************************************What can we do with this taxonomy?
The initial purpose of defining information types using a set of properties was to help me distinguish perceptual and linguistic information. So, I hope this taxonomy will help structure further empirical work on an ecological approach to language. But, the taxonomy has now grown to encompass other types of information. I think this broader set of properties could be useful in the domain of animal cognition. The taxonomy provides a language for comparing any behaviours that are precipitated by structure in an energy array. Take, for example, vervet monkey calls. Vervets have a small vocabulary of calls that they use to warn each other about potential danger (e.g., hawk). Vervet's respond to these calls with specific, functional behavior (i.e., they don't just run) and they respond even when there is no perceptual evidence of the threat (i.e., they can't see a hawk).
Even though this is clearly an example of vervet monkeys using symbols to communicate, no one is tempted to say that they are using language. The traditional move is to say that the animal calls lack essential properties of language use (e.g., productivity), but precisely which properties are essential to language is highly debated (see Chompsky versus Everett on recursion). The taxonomy outlined in this post provides another way of comparing vervet calls to human language. For example, do vervet monkeys have to learn to coordinate their behavior to the calls (i.e., are the calls at Pole 1 or Pole 2 for the Learning dimension)? If the link between vervet calls and behavior is relatively fixed (Pole 1), then this is an important difference from human language, where the same acoustic information can mean different things across languages.
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So, this is what I've come up with for now. The big challenge at the moment is figuring out how to communicate these ideas efficiently. I've been thinking about this stuff for months and I still have to refer back to what I've written to remember what the different poles are. And the table I've included is, admittedly, not very helpful. If anyone has any clever ideas for presentation, I'd love to hear them!