Chapter 4. Nature, Nurture, and their Interaction

4.1 Introduction

Try This!

Interactive Exercises to Accompany

Psychology: The Science of Person, Mind, and Brain

Tracy L. Caldwell, Dominican University

Daniel Cervone, University of Illinois at Chicago

4.2 Slide 2

Welcome to your Try This! research experience for Chapter 4. As you learned when reading the chapter, you will be asked to try your hand at solving some problems.

As you try them, ask yourself this question: What might these problems have to do with the topic of this chapter, nature and nurture?

We’ll begin with some background on your first problem.

4.3 Slide 3

Suppose you have an clerical job at a local high school. Once of your duties is to process documents correctly, according to a coding system employed at the school.

In the following problem, your job is to ensure that documents are processed according to the following rule:

If a person has a “D” rating, then his or her document must be marked with code “3.”

You suspect that someone working before you did not categorize documents correctly. On the next screen, you will see four cards. Each card displays information about one person enrolled at the high school. One side of the card tells a person’s letter rating and the other side of the card tells that person’s number code. The screen will display one side of each of the four cards; thus, on each card, you will see either a letter rating or a numerical code.

Your task is to indicate only the card(s) you definitely need to turn over to see if the documents of any individual people violate the document processing rule stated above.

4.4 Slide 4

4.5 Slide 5

Thanks! One more problem, then we’ll give you some feedback.

In the next problem, imagine you are Resident Assistant in a dormitory. People are allowed to drink beer only according to the following rule:

If a person is drinking beer then he or she must be over 20 years old.

You suspect that there has been quite a bit of underage drinking in the dormitory and you have been asked to crack down on the “cheaters.” On the next screen, you will see four cards. Each card displays information about a resident in the dormitory. One side of the card tells the drink the individual enjoyed last Saturday night and the other side of the card tells that person’s age. The screen will display one side of each of the four cards; thus, on each card, you will see either a drink or an age.

Your task is to indicate only the card(s) you definitely need to turn over to see if individuals are drinking when underage.

4.6 Slide 6

4.7 Slide 7

You’re finished! On the first problem, your answer was to turn over card(s) _______.

The correct answer is to turn over only cards D and 7. Here’s why.

• If the card with the D has anything other than a 3 on the back, it will violate the rule. So that’s a necessary card to turn over.
• The card with the F can have any number behind it (including 3) without violating the rule, so that’s not a necessary card to turn over.
• The “3” card doesn’t need to be turned over either, because the rule doesn’t limit “3” codes only to D’s.
• If the card with the 7 has a “D” on the back, it will violate the rule, so you know you have to turn it over to check it.

In the research by Leda Cosmides (1989) that inspired this activity, only 4% to 25% of college students got this problem correct!

4.8 Slide 8

On the second problem, your answer was to turn over card(s) ______.

The correct answer is to turn over only the cards that say “beer” and “17.” Here’s why.

• If the beer card has an age of 20 or less on the other side, you’ll know the student has violated the rule, so that’s a necessary card to turn over.
• The Coke card can have any age behind it without violating the rule, so that’s not a necessary card to turn over.
• The age 22 card doesn’t need to be turned over, either, because the rule doesn’t limit the type of beverage a person that age can consume.
• If the age 17 card lists beer on the other side, you’ll know the student has violated the rule, so that’s necessary to turn over.

Considerably more college students got this problem correct: 75% (Cosmides, 1989)!

4.9 Activity completed!

So what do these problems have to do with the topic of the chapter, nature and nurture?

Before you return to the text for a detailed explanation, consider how the two problems differed. One asked you to consider whether documents are categorized correctly and the other asked you to consider whether people were “cheating” when it comes to the rule of underage drinking.

Which of these problems – categorization of written documents versus cheating detection – would our ancestors have been more likely to face? Keep your answer in mind as you return to the text.