Ad hoc cognition

I heard about lots of cool research this past weekend at Psychonomics – how taking photos affects our memory (not positively), how we prefer musical meters (i.e. 3/4 or 6/8) that we’ve been exposed to earlier, and how we tend to use the same syntactic structure to talk about things as was used when we learned them (even when we’ve heard other structures between the learning and talking).

But my favorite group of talks was a block on Ad Hoc Cognition – the idea that our mental categories, concepts, and word meanings are not stable, but are constructed each time we use them. Daniel Casasanto presented a great example of this theory. We might consider that everyone has a relatively similar concept of what constitutes furniture, or at least that one person’s mental category for furniture is always the same. It’s probably made up of things like tables, chairs, and couches. But what about when you’re camping and someone says, “We need some furniture for this bonfire. Let’s pull over that log.” Although logs aren’t typically included when we think of furniture, in that moment, it seems appropriate to call a log a piece of furniture. We have no problem constructing our idea of what belongs in the furniture category on the spot (ad hoc), and the larger argument is that we’re constantly doing this.

Jeff Elman also presented some cool evidence demonstrating the same point. He (and others) have measured the electrical activity along people’s scalps (using EEG) that occurs when people read sentences, and have found that people have different expectations for what words should come next depending on the context. For example, in the context of an ice skater who just won a championship, when people read “the crowd roared as she took her place on the podium,” they show no evidence or surprise at the word podium (this would be demonstrated by a spike in activity 400ms after the word podium was presented, also known as the N400 component). When they read that “the crowd roared as she took her place on the medal,” they show a medium N400 response, indicating that they were moderately surprised by the word medal, which doesn’t actually make sense but is an object that would likely be involved in the situation. When they read that the “crowd roared as she took her place on the beach,” which makes no sense and should also not be associated with the situation, they show the largest N400 response, or the most surprise. The fact that the responses to bleach and medal differ even though neither makes logical sense shows that people are constantly constructing expectations based on context.


So if we’re constructing our concepts, categories, and word meanings (CC&Ms) on the spot in a new way for every concept, is it futile to study our mental CC&Ms? Casasanto gave a helpful analogy to show that studying how we think about these things is still fruitful, even if they’re context-dependent and therefore unstable. Just as physicists know that Newtonian physics is not quite accurate and that the theory of general relativity is more scientifically sound, we still rely on Newtonian physics all the time – when we go on a diet, we use a scale to measure our mass, since the Newtonian concept of mass is good enough for what we need). Returning to mental concepts, if a child asks you what a plethora is, it’s probably not a good idea to respond that it’s an ill-formed question, since our idea of plethora is constantly constructed from context. We can come up with a definition of plethora that’s close enough for many purposes, and the kid will not be living a lie if he doesn’t acknowledge that the meaning might differ slightly from one context to the next. However, it’s important for people who research CC&Ms for a living to honor their context-sensitivity and bear it in mind as they go about defining and exploring these nebulous ideas.

What does “American” mean?

There aren’t many words whose meanings I haven’t immediately grasped upon being introduced to them. But as I was reflecting on the anniversary of the events that happened 12 years ago, I realized that my understanding of the word “American” has been evolving and deepening for my whole life, and I suspect that it’s still far from complete. I also suspect that this one word has an extremely powerful impact on everyone who identifies as an American, and that that meaning is probably a little different for each one of us.

When I was little, being American meant saying the pledge of allegiance every day in school, even if the phrase “…and to the republic, for which it stands…” never really made any sense. It also meant memorizing the 50 states song, which listed all the states in alphabetical order, as well as the preamble song. Being American meant celebrating the 4th of July by covering our bikes in gaudy red, white, and blue streamers and joining all the other neighborhood kids in a bike parade. It also meant wearing an Old Navy flag t-shirt and probably those flip flops that had stars on the left foot and stripes on the right. Fireworks and sparklers were also imperative.


By the time I went to live in France for 4 months, I was almost 20, and my patriotism was in need of a boost. Luckily, my séjour in Paris provided me with just that. I began to appreciate more American luxuries like having eggs for breakfast, running errands on Sundays, and public transportation that actually runs when it’s supposed to (to be fair, the Parisian Metro is great, except when they decide they need to spice life up a little and strike… which is much too often). I also started to fully grasp the concept of the self-made American man, and why it’s one that sets America apart from others. I started to truly understand why America prides itself as the land of the free and the home of the brave.

Even recently, I’ve had the opportunity to explore a great variety of places in America, and these have all shaped my understanding of what “American” means. The essence of the word was captured this past 4th of July, listening to the Boston Pops perform at the Hatch Shell, followed by fireworks over the Charles River. It was clear in the billboards, neon lights, and smells of grilling hot dogs as I approached Times Square late one night. The meaning of “American” was pretty clear as I rode down the Pacific Coast Highway, the ocean immediately to my right, mountains to the left.

Tonight, my working definition of “American” is still a little hazy. It has something to do with picking apples and turning them into pies right around the time of year when the leaves turn vibrant shades of yellow and orange. Being American also has something to do with riding down the highway, blasting country songs in which men sing about their women, their pickup trucks, and their beer. My understanding of “American” also includes Thanksgiving, a day in which we watch football (the football that requires helmets and shoulder pads), spend all day preparing and eating the food we imagine the Pilgrims ate, and proceed to stimulate our economy the following day. America isn’t perfect – for example, that first Thanksgiving likely marked the beginning of a long history of mistreating Native Americans – but any nation who can come out of a tragedy such as the attacks of 9/11 as a stronger and more unified nation is pretty awesome in my book.


A new way of looking at vision

Visual processing has always been one of the topics in cognitive science that interests me the least, but after reading this paper, “Constructing Meaning,” by Seana Coulson, I’ve changed my mind (at least a tiny bit). Instead of ascribing to the folk psychological view of vision as a “passive registration process in which people record optical information that exists in the world,” she suggests that it’s an “active, constructive process in which people exploit optical information to interact with the world.”

Early accounts of vision represented it as a hierarchical, feed-forward process, but more recent studies have revealed that there are in fact a number of backward connections, in which information is passed from higher-level areas to lower, as well as a number of lateral information transfers. Vision isn’t as simple as was once thought.

As if this wasn't already complicated enough, there's more than this to vision! Image:
As if this wasn’t already complicated enough, vision is even more complex than this!

Further demonstrating this point is the notion of context sensitivity. One example is the phenomenon of color constancy: even when lighting conditions change, the color we perceive objects remains constant. Another example is neural filling-in. We all have a blind spot, the region of the retina where the optic nerve attaches and there aren’t receptors, but we don’t perceive the small hole in our visual field that we would if our brains weren’t somehow filling in the gaps. This is a specific example of the more general problem that despite frequent blinks (about every 5 seconds), we don’t experience perceptual discontinuity. And a final example that I thought was earth-shattering the first time I read Noe’s account of it: when we look at an object, we’re actually only seeing it in two dimensions, but we perceive the whole of it in its three-dimensional glory.

The short story: we don’t perceive what’s actually there, but instead construct a representation of what we’re seeing based on context and prior knowledge of the world around us.

Then Coulson likens the process of visual perception to language processing. Making meaning out of an utterance is not simply a decoding process based solely on the linguistic information, just as visual perception isn’t simply passively absorbing visual stimuli. Instead, perceiving linguistic meaning involves a complex interplay between linguistic and nonlinguistic knowledge. After reviewing quite a bit of cognitive neuroscience data, Coulson concludes that the studies “argue against a deterministic, algorithmic coding and decoding model of meaning, and for a dynamic, context sensitive one.” I thought this paper was a really cool way of saying that context is crucial for making meaning, whether out of visual or linguistic input, rather than an incidental property of the stimuli.