Web Activity 11.2 Investigating mental models

In the textbook you read about MacDonald and Just’s (1989) memory probe study (see pp. 450–452). As discussed in Method 11.1, memory probe studies have some limitations, which has driven researchers to look for converging evidence using other methods including reading time measures.

It is possible to create a simple reading time version of the study by MacDonald and Just. For example, we can use their original stimulus sentences as a starting point and adapt them so that a subsequent sentence is either consistent or inconsistent with the information we think is being represented in the mental model. A contrasting pair of stimuli from different conditions might look like this:

1. Simon baked some cookies and some bread.
   The bread was made from whole wheat.
2. Simon baked some cookies but no bread.
   The bread was made from whole wheat.

The use of the phrase the bread is inconsistent with a mental model in which there is no actual bread, so we would predict that reading times for the second phrase would be longer in b than in a.

In some cases, it might be a bit less straightforward to take a memory probe study and create a corresponding reading time version to get at the same question. Do your best with the following examples, creating sample stimuli and making a specific prediction. How easy is it to propose a reading time study to capture many of the same insights as those in the studies below? Do you come across any difficulties in trying to formulate stimuli that will achieve as closely as possible the goals of the memory probe studies? What potential problems do you run into in interpreting the reading time results?

A. Glenberg et al. (1987)

In this study (discussed on p. 452), the researchers found that responses to the memory probe sweatshirt were slower in b than in a, suggesting that the sweatshirt was represented less robustly in the mental model if it had become physically separated from the protagonist:

1. John was preparing for a marathon in August. After doing a few warm-up exercises, he put on his sweatshirt and went jogging. He jogged halfway around the lake without too much difficulty. Further along his route, however, John’s muscles began to ache.
2. John was preparing for a marathon in August. After doing a few warm-up exercises, he took off his sweatshirt and went jogging. He jogged halfway around the lake without too much difficulty. Further along his route, however, John’s muscles began to ache.

B. Suh and Trabasso (1993)

The researchers used a memory probe task to measure the accessibility of goals that are either resolved or unresolved in a text. They compared texts like a and b and had subjects respond to the memory probe buy a bike at a variety of different probe locations, as shown below. (It is worth emphasizing that in memory probe studies, each subject sees only one version of the text and gets a memory probe in just one position. Statistical comparisons rely on observations from many subjects responding to different variants of the stimuli.)

1. Once there was a boy named Jimmy.
   One day, he saw his friend, Tom, riding a new bike.
   Jimmy wanted to have a new bike.
   He spoke to his mother.  (P1)
   His mother refused to buy him a bike.
   Jimmy was very sad.
   His mother told him that he should have his own savings.
   Jimmy wanted to earn some money.  (P2)
   He asked for a job at the grocery store.  (P3)
   He made deliveries for the grocery store.
   He earned a lot of money.
   He went to a department store.
   He walked to the second floor. (P4)
   He bought a new bike.
2. Once there was a boy named Jimmy.
   One day, he saw his friend, Tom, riding a new bike.
   Jimmy wanted to have a new bike.
   He spoke to his mother.  (P1)
   His mother bought him a bike.
   Jimmy was very happy.
   His mother told him that he should have his own savings.
   Jimmy wanted to earn some money.  (P2)
   He asked for a job at the grocery store.  (P3)
   He made deliveries for the grocery store.
   He earned a lot of money.
   He went to a department store.
   He walked to the second floor.  (P4)
   He bought a new basketball.

There was no significant difference in response times for the two versions of the text at probe position P1. At probe position P2, response times were slower for the probe buy a bike in version b than in version a, suggesting that unresolved goals remain more active in memory than resolved goals. However, at P3, there were no differences in response times for the two versions. But at P4, responses to the probe were once again slower in version b than in a, suggesting that the unresolved goal had become reactivated in memory.

C. Perceptual information

Testing for perceptual information in a mental model poses special challenges. In Section 11.1 you read about a memory probe study for auditory information associated with the events in a text . Can you think of an alternative way—either through a reading time task or some other method—to see whether certain kinds of perceptual information are instantiated in a mental model?

References

Glenberg, A. M., Meyer, M., & Lindem, K. (1987) Mental models contribute to foregrounding during text comprehension. Journal of Memory and Language, 26, 69–83.

MacDonald, M. C., & Just, M. A. (1989) Changes in activation levels with negation. Journal of Experimental Psychology: Learning, Memory, and Cognition, 15, 633–644.

Suh, S., & Trabasso, T. (1993) Inferences during reading: Converging evidence from discourse analysis, talk-aloud protocols and recognition priming. Journal of Memory and Language, 32, 279–300.