Transcript The Origins of Mating Behavior

The Origins of Mating Behavior
Evolutionary Psychology
Dr. Kelley Kline
FSU-PC
I. Mating: Evolutionary Roots
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Darwin observed that many animals exhibited physical &
behavioral characteristics that “appeared” to hinder the
animal’s chances for survival (e.g., colorful plumage of a
peacock). Yet these characteristics appear to be selected
for in nature.
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Class: What was Darwin’s answer about why this
phenomenon should occur, if it appeared to threaten the
animal’s chances for survival?
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Darwin argued that some features are selected for and
thrive in nature due to their reproductive benefits of
passing on the genetic line, rather than survival
benefits. THIS IS CALLED SEXUAL SELECTION!!
II. What are the two forms of Sexual
Selection?
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1. Competition for a mate.
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2. Preferences for a mate.
A. Competition for mates:
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Intrasexual selection—occurs when members of the
same sex compete with each other for access to
members of the opposite sex.
 (E.g., two stags locking horns in combat, two lions
fighting for access to viable females, two males getting
into a bar room brawl fighting over a woman, etc.)
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Class: Why do members of the same sex compete with
each other for mates according to evolutionary theory??
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Characteristics that lead to success in these contests
evolve because the winners are able to mate more often
and consequently are more likely to pass on their genes.
What are some characteristics exhibited by
intrasexual competitors that may increase
their chances of winning?
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Greater strength, intelligence, cunning,
attractiveness, derogating rivals, etc.
E.g., The stronger male lion will successfully
either kill/scare the other male lion away,
thereby granting the victor access to the
females in the pride.
B. Preferences for mates:
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Intersexual selection – members of one sex choose a
mate based on preferences for particular qualities in that
mate.
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Characteristics preferred by members of the opposite
sex, evolve to become more common over time. Why
Class???

These characteristics evolve because animals possessing
them are chosen more frequently to be mates, and as a
result, their genes are more likely to be passed on.
 --Animals lacking desired characteristics are chosen
less frequently to be mates.
III. Sexual Strategies:
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Like successful foraging for food, finding water, and
building shelter, we don’t approach mating behavior
without a plan.
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Human mating behavior has evolved so that we choose
mates who are desirable, reproductively viable, likely to
invest in us, & so forth. Why Class???

In our evolutionary past, those who failed to mate
successfully failed to become our ancestors. We all are
products of an ancestral line who competed
successfully for desirable and reproductively viable
mates. Otherwise, “we” simply wouldn’t be here!!!!
A. Problems solved by Sexual
Strategies:
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We have several mating strategies we employ that
are designed to solve specific mating problems.

Class—What are some of the basic mating
problems that need to be solved?
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Selecting a desirable mate
 Attracting a mate
 Replacing a mate
 Keeping a mate (mate retention, mate guarding)
B. There are two basic types of sexual
strategies:
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1. Short term mating (casual sex) – involves
mechanisms designed to procure a mate for a short
period of time.
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2. Long term mating – involves mechanisms designed
to procure a mate for a long period of time (possibly
life).
 Note: We will learn that often similar tactics are used in both
types of sexual strategies making it difficult for the individual to
determine which type is being sought. For example, males often
use deception (being overly friendly, generous with money & gifts,
to achieve short term mating goals, when the female may
misperceive these gestures as pursuing long term mating goals.)
Points about sexual strategies:

We are not always consciously aware of the sexual
strategies we employ in mating.

When we become aware of the strategies we are
using to procure mates, it often impedes our
performance.

Buss, has examined these strategies in a study of
over 37 countries and has found robust evidence to
support these tactics as hard-wired in our systems.
Its not a cultural phenomenon.
1. Selection a Mate:

Class—What factors come into play when we select a
mate???
It’s adaptive to select mates who:
 Are willing to provide abundant resources
 Protect us & our offspring
 Devote time, energy, money, & effort in us.
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This increases the chances that our offspring will thrive
and survive.
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Thus, we have evolved preferences to seek mates
possessing these qualities.
According to the evolutionary theory, do
men & women seek the same
characteristics in a mate??

Class what do you think???
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No, men and women have different reproductive
costs, which impacts the preferences they develop
for future mates.
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As women have a greater physical investment
bearing & caring for children (40 week gestation)
then men do, they seek more long term mates.
2. Attracting a Mate:
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It’s not enough to select a mate, but we have to engage
in behaviors to attract the mate we are interested in.
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Factors that have worked over time to procure mates
are:
Competition
Showing off one’s attractive qualities (e.g., peacock
showing a peahen his gorgeous plumage, males flexing
their muscles for female passerby)
Derogating rivals
Ingratiating oneself to the mate.
Showing willingness to invest/commit (expending
resources, being friendly/chivalry)
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Why do these factors work in attracting
mates?
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If these tactics led to more frequent & fruitful
mating, then individuals using these tactics,
would be more likely to reproduce & pass on
their genes.
 (e.g., elephant seals have evolved to become
large and heavy, thereby strengthening their
chances of mating with females in the harem &
warding off other male competitors.)
3. Keeping a mate:
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Just because we may select and attract a mate
successfully, doesn’t mean we will hold onto the
mate indefinitely.
We may lose mates because:
 Another suitor may poached (stolen)
 One mate may defect –due to the failure of the
other mate to fulfill the defecting mate’s needs.
 A more desirable mate may come along.
Mate Retention, Infidelity, & costs:
Males who don’t guard access to their mate, may risk
raising a child who is not their biological heir. Hence,
sanctioning his mate’s access to other males, is one way
to decrease paternity uncertainty.
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Tactics employed: mate guarding, restricting female’s
access to other males, derogating rivals, violence
towards other males.
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Females who don’t guard their mates, may risk losing a
male & his resources to another female & her offspring.
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Tactics employed: mate guarding, keeping oneself
physically attractive, befriending female competitors to
keep them in check, derogating rivals.
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4. Replacing a mate:
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Sometimes a mate shouldn’t be retained, but discarded
and replaced.
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Why class??
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We rid of mates when:
They stop offering resources (money, sex, support, etc.)
They are cheating
They are infertile
They are hostile or harmful to us
The benefits of losing the mate outweigh the costs
(depends on what our market value is following the
break-up)
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Reentering the mating market: costs
and benefits
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Class, what are the relative costs and
benefits that occur for men and women as
they reenter the mating market??
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How do the presence of children and age
of a mate impact their relative value on the
mating market??
Conflict between the Sexes
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Men and women clash over resources (money,
status, power) & sexual access (frequency, etc.).
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Male desire for short term mating strategies get in
the way of women’s long term strategies.
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Men and women both complain about portion of
domestic work and who gets off easier.
Culture & Context
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Although this course will focus on the
evolutionary theory as it applies to mate selection,
the influence of society and culture is still
important in explaining our behavior.
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It’s important to note that our mating behavior and
social system have changed far more rapidly than
our evolutionary history, such that over time our
preferences/desires in mating may change.