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Psychology 305A: Personality Psychology

October 3

Lecture 8

Psychology 305 2

Scoring Your Questionnaire: EAS

1. Reverse score items 6, 18, and 19 (change 5 to 1, 4 to 2, 2 to 4, 1 to 5).

2. Sum the following items:

• 2, 7, 10, 17 • 1, 6, 15, 20 • 5, 8, 13, 18 • 4, 9, 11, 16• 3, 12, 14, 19

3. Divide each sum by 4.

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A little R&R ….(Review and Reflect)

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1. What hypotheses has the evolutionary approach generated regarding (a) sex differences in jealousy and (b) birth order and personality?

The Biological Perspective

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2. What are the goals of behavioural genetics?

3. What are heritability and environmentality and how are they assessed?

By the end of today’s class, you should be able to:

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1. review research supporting evolutionary hypotheses related to sex differences in jealousy.

3. describe the “principle of divergence.”

2. discuss the influence of birth order on the Big 5.

4. discuss criticisms of the evolutionary approach.

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What hypotheses has the evolutionary approach generated regarding sex differences in jealousy?

• Once a mate has been selected with whom to copulate, females and males encounter different adaptive problems:

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Males: Must ensure that their mates do not copulate with other males, as this would result in uncertainty regarding the paternity of offspring.

Females: Must ensure that their mates do not withdraw care and resources, as this would jeopardize the survival of offspring.

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• Following from these adaptive problems, evolutionary psychologists generated two hypotheses:

Hypothesis B: Males are more likely than females to become jealous in response to cues that suggest sexual infidelity.

Hypothesis A: Females are more likely than males to become jealous in response to cues that suggest emotional infidelity.

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• Studies that have tested these hypotheses include:

Buss et al. (1992; see also Buunk et al., 1996; Miller & Maner, 2009; Schutzwohl & Kock, 2004):

Presented participants with the following dilemma:

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Psychology 305 10

Think of a serious, committed romantic relationship that you had in the past, that you currently have, or that you would like to have. Imagine that you discover that the person with whom you’ve been seriously involved has become interested in someone else. Of the following, what would distress or upset you more?

1. Imagining your partner forming a deep emotional attachment to that person.

2. Imagining your partner enjoying passionate sexual intercourse with that other person.

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Results consistent with Hypotheses A and B.

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Brase, Caprar & Voracek (2004): Found similar sex differences in China, Germany, the Netherlands, Korea, Sweden, Japan, England, and Romania.

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Pietrzak et al. (2002): Found similar sex differences using physiological measures (e.g., heart rate, skin conductance, facial expressions).

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What hypotheses has the evolutionary approach generated regarding birth order and personality?

• Most animals require some degree of parentalinvestment (i.e., resources) in order to survive.

• When parents have more than one offspring, siblings must compete for parental investment.

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• Evolutionary psychologists maintain that first-born children (FBs) and later-born children (LBs) have developed different strategies to maximize parental investment.

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• E.g. of strategies used by FBs in non-human species:

Predatory birds confronted by a scarce food supply: Older chicks attempt to peck younger chicks to death or exclude them from the nest.

Cuckoo birds: First chick to hatch attempts to eject all other eggs from the nest.

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• For humans, evolutionary psychologists generated three hypotheses regarding the strategies that FBs and LBs

use to maximize parental investment and their impact on personality:

Hypothesis A: FBs are higher in extraversion than LBs.

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Hypothesis B: LBs are higher in agreeableness than FBs.

Hypothesis C: FBs are higher in neuroticism than LBs.

By the end of today’s class, you should be able to:

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1. review research supporting evolutionary hypotheses related to sex differences in jealousy.

3. describe the “principle of divergence.”

2. discuss the influence of birth order on the Big 5.

4. discuss criticisms of the evolutionary approach.