Modeling the Detection of Early-Evolving Melanoma Symptoms: Role of Cancer Information and Delay Discounting

Abstract

Young adults became familiar with sample images showing the presence and absence of melanoma symptoms, and on each of a series of subsequent test days rated whether a single lesion image had changed from the asymptomatic sample. In general, as symptom severity of the test lesions increased, participants became increasingly likely to report change, with no global differences apparent for groups distinguished by whether they encountered symptom evolution sooner versus later or whether they had or had not encountered cancer information similar to that used in melanoma patient education. Within groups there was considerable variability in individual detection behavior, and this variability correlated with a measure of delay discounting such that less impulsive individuals tended to detect smaller stimulus changes. Signal detection analysis revealed a general bias against reporting stimulus change, with more impulsive individuals showing more pronounced bias. In placing melanoma symptom detection behavior within an impulsivity framework, the present study suggests that a single approach to patient education may not be equally appropriate for all individuals.

Appendix

Instructions for Delay Discounting Task

Pretend you just won $100. Congratulations! The only problem is that today you just get a voucher (an “IOU”) for that money, but you can’t trade the voucher for cash today. Instead, the money will be paid at a later date. In this survey we want you to think about how it would feel if the money were delayed by different amounts of time, as shown at the top of the columns below. For each column, imagine that someone wants to buy your voucher and will pay cash right now for it. Since you can’t trade the voucher for money until a later date, the buyer isn’t likely to pay full price. For each column, circle just one number to show the smallest amount of money you would accept right now in exchange for your $100 voucher. In deciding your rock-bottom price, keep in mind the delay (top of each column) until the $100 you are “selling” would be paid.

Instructions for Orientation Session

Cancer Orientation Groups

This study of visual perception focuses on the symptoms of a disease called melanoma. Melanoma is the most serious type of skin cancer, and it affects more than 50,000 people a year in the United States. Melanoma begins in skin cells called melanocytes. These cells make the skin pigment melanin, which in light-skinned people tends to be concentrated in moles and freckles. The first sign of melanoma is often a change in the appearance of an existing mole. Noticing the first signs of melanoma is very important. If melanoma has spread to other parts of the body, it can be difficult to treat and often is deadly. If, however, melanoma is diagnosed early, chances are high for a full recovery after treatment. In a moment you will become familiar with an image that we’ll call “Image B.” Later you’ll see a whole series of test images. Your job is to decide whether each of the test images matches Image B.

Neutral Orientation Groups

This is a study about visual perception. Many everyday experiences require us to use our vision to tell one thing from another. When two objects are very different, this judgment is not difficult. A different kind of perceptual challenge arises when we judge whether an object has remained the same or begun to change. Imagine tending a plant in your garden, cooking a piece of meat on your stove, or deciding whether to paint your house. All of these things involve deciding whether an object has changed from how it used to be. Big changes are easy to notice—for example, if your plant has blossomed, your meat has burned, or your house paint has all peeled off. It is harder to notice the first, small signs of change. In a moment you will become familiar with an image that we’ll call “Image B.” Later you’ll see a whole series of test images. Your job is to decide whether each of the test images matches Image B.

Instructions for Preliminary Training

Cancer Orientation Groups

Today we will show you an example of a “starting” mole that has no melanoma symptoms (“Image B”). We will also show you an example of a mole that exhibits melanoma symptoms (“Image M”). We ask you to imagine that the symptom-free Image B is your own skin, and that symptomatic Image M is what your skin could become if there were a problem. Your job today is to learn to tell Image B and Image M apart. We think that this will be fairly easy to learn.

Neutral Orientation Groups

Today we will show you an example of a “starting” shape that is unchanged (“Image B”). We will also show you an example of shape that has changed (“Image M”). Your job today is to learn to tell Image B and Image M apart. We think that this will be fairly easy to learn.