Assignment 4: Psycholinguistics Experiments, Categories and Prototypes
Assigned Friday, February 25th
Due Friday, March 3rd, by 11:59pm - submit electronically.
In this assignment, you will apply some of the ideas from cognitive linguistics that you have seen in lecture and the readings (R10, R14 ch 3)

Problem 1

Here are some types of prototypes and prototype effects, and the forms of reasoning with which they are usually associated:

Choose a category (not taken from the lecture/readings) that includes at least 5 of these kinds of prototypes. (If you have difficulty with this, you may use more than one category, but be sure to answer both questions below for each category you consider.)

1. Give a brief description of the internal structure of your chosen category. Does it have a central case (or cases)? If so, what properties hold for the central case?
2. Briefly describe 5 prototypes or prototype effects relevant to your category, and show how each gives rise to the type of reasoning indicated. (If necessary, provide context/reference to indicate where you found the examples.)

Problem 2

The study of color concepts serves as an ideal case (or at least a salient example) of how cognition and conceptualization may be embodied in the human neural system. Using color as a model, pick a different domain of embodied concepts and speculate about how it may arise from the neural system. Possible domains include (but are not restricted to) locomotion, manipulation of objects, temperature, emotions.

1. What are the basic-level categories in your chosen domain?
2. What gives rise to this domain and the category structure within it? What interacting factors are involved? Try to be specific about the biological underpinnings of the domain. What kind of additional biological evidence would be necessary to support the claim that your chosen domain is embodied?
3. Based on your analysis, what kind of crosslinguistic variation would you expect for this domain? Feel free to cite linguistic examples if you know of them.

Problem 3

Recently, we discussed fMRI experiments by Buccino et al., 2001 showing somatotopy of action observation in humans, and fMRI experiments by Pulvermuller et al., 2004 that showed somatotopy during an action word task.

A series of behavioral and imaging experiments studied category-specific impairments to semantic memory in patients with brain lesions, suggesting that different parts of the brain are used to encode, for example, animate versus inanimate objects. And indeed, Martin et al demonstrated that different regions of the normal brain are associated with animals versus tools, using the imaging technique known as positron emission tomography (PET) (Martin et al., 1996). Subjects were asked to identify animals and tools while they undergo PET scans. While some areas of the brain were active in both tasks, naming animals selectively activated the left medial occipital lobe, and naming tools selectively activated the left premotor area and the left middle temporal gyrus. (The left medial occipital lobe is traditionally associated with visual processing, whereas the premotor area is traditionally associated with making movements, the temporal gyrus with generating action words. )

Now, we would like to (i) repeat the PET experiment using fMRI, and (ii) perform a behavioral experiment that shows the effect of shared processing area on reaction times in a matching task. Here is the design of our experiment:

Part 1

We would first like to find further evidence for the use of different brain regions for processing animals and tools. Our hypothesis is that certain regions of the brain will be selectively activated for animals and certain others for tools.

The stimuli consist of 24 line drawings and can be evenly divided into four categories: noise patterns, nonsense objects, animals, and tools. Nonsense objects include: randomly crossing lines, 3-D shapes that do not correspond to real live objects. The animals are: a dog, a horse, a wolverine, a capybara, a giraffe, a badger. The tools: a wrench, a hammer, a lathe, a screwdriver, an embosser, a chainsaw.

Each subject is presented with the sequence of 20 stimuli in random order, and is asked to name each stimulus silently. Each stimulus is presented for 100ms, followed by a centrally located fixation cross for 500ms. An fMRI snapshot is taken 150ms after the stimulus is presented. Each subject is told that he will be asked a question about the pictures at the end of the fMRI session to make sure he pays attention during the experiment.

At the end of the experiment, for each subject, we will compare the fMRI images across different stimuli. We will do four kinds of comparisons: (1) subtracting activation due to noise patterns from activation due to animals and tools, (2) subtracting activation due to nonsense objects from activation due to animals and tools, (3) subtract activation due to animals from activation due to tools, and (4) subtract activation due to tools from activation due to animals.

1. Does this experiment test our hypothesis? What kind of results will confirm (or at least not disprove) our hypothesis?
2. What are possible flaws of our experiment setup? How can you improve it?

Part 2

Let's say we do confirm that different brain regions are used for processing animals and tools. We would now like to test in a picture-word matching task whether there are facilitatory / interference effects based on the brain regions used. Our hypothesis is that if the picture and word do not match, but are from the same category, we should see interference effects.

In this behavioral experiment, each subject is first presented with a picture stimulus (150ms) followed by a word (150ms). Her task is to determine whether the word matches the picture by pressing either the ' yes' button or the 'no' button as quickly as possible, and her reaction time is recorded. Each subject goes through 20 pairs of stimuli (in random order). Here are some representative examples of pairs of stimuli that the 20 pairs are drawn from:

At the end of the experiment, for each subject, we will group their reaction times into four groups for comparison: (1) matching picture and word, (2) mismatch where the picture and words are in different categories, (3) mismatch where both pictures and words are animals, mismatch where both pictures and words are tools.

1. Does this experiment test our hypothesis? What kind of results will confirm (or at least not disprove) our hypothesis?
2. What are possible flaws of our experiment setup? How can you improve it?