PSYC 102
April 22, 2008
*Identifies what types of attractions in members of opposite sex would have enhanced reproductive success in our ancestral past.
I. Thomas Aquinas on Marriage
1. We observe in those animals, dogs for instance, in which the female herself suffices for the rearing of the offspring, the male and female stay no time together after the sexual act. But in animals in which the female herself does not suffice for the rearing of the offspring, male and female dwell together after the sexual act so long as is necessary for the rearing and training of the offspring. This appears in birds whose young are incapable of their own food after they are hatched… Hence, whereas it is necessary in all animals for the male to stand by the female for such a time as the father’s concurrence is requisite for bringing up the progeny, it is natural for man to be tied to…one woman for a long period…
*one parent stays only if it is needed for the rearing of the offspring. It does what is in the best interest.
*this is not true in birds…it is in the males best interest to hang around for the survival of the offspring.
2. Where the offspring require nurture and care, typically that leads to longer associations between male and females because they have a common interest in genetics surviving in the offspring…higher reproductive offspring etc.
3. The degree of parental investment is not the same between males and females or in species.
 a. Species vary in amount of investment between male and females. For example, in humans, the female is more responsible for nurturing and caring for offspring.
a. Advantages/Disadvantages of being male (from reproductive success standpoint)
1. ADVANTAGE>>Sperm is very cheap…not much effort at all. There are tons of it out there. This can cause minimal investment in the female and the ability to fertilize as many females as possible and have minimal responsibility in the females. (Ex. Dogs go from one female to the next and guard their territory). Humans are not like this. Females need a male mate (or some other source) to help raise the offspring. There is a relationship between the degree of paternal investment and the success of the offspring. Without the male, the success of the offspring goes down…they need investment. This is true in other species as well.
2. DISADVANTAGE>>Low paternity certainty….If you are trying to inseminate as many females as possible, you will not know for sure if those offspring are yours and carry your genetics. The male will be uncertain if he is not around to know if the female has mated with other males.
1. High maternity certainty: The female knows she has an investment in the genetics of the offspring
2. DISADVANTAGE>>costly eggs: relatively high parental investment…eggs are high compared to sperm. She needs and tries to get as much help from the male as possible.

DEMONSTRATE IT IS UNIVERSAL ACROSS HUMANS: gives us confidence if all the same traits are present, we know it is a part of being human. It must cross all cultures etc. It is an evolved aspect of the species.
a. Global study on mate attraction. Did the largest cross-cultural study known. Ended up with 10.000 subjects from over 30 countries across the globe.
b. Looking for universal attractions across human males and females simply because they were human.
c. Hypothesis was that in females we would expect any universal attraction to males would be linked to decreasing their parental investment and increasing investment by getting good genes and help from the males (copious resources.)
1. Must have robust and healthy offspring…decreases need for care. Grows up without much effort giving room for new offspring.
d. Males would be about increasing paternity certainty (make sure they are his offspring) and increasing the output of the female…(have more of his genetic offspring).
1. These are general patterns across the many cultures. These patterns reflect all of the cultures.
a. AGE: Across cultures, the males are attracted to a younger female…this is for long-term relationships. Patterns are different for short-term relationships. *This is so the male insures a longer reproductive period for the female. It also is less risky for a man to guard an older, more experienced woman than a younger woman. This can lead to better paternity assurance when the younger female is his mate.
b. BEAUTY: Cross culturally, men want the pretty female. No one wants an ugly mate. Everyone said that beauty was very important. The males want this more than females. *Pretty is a proxy for health. Certain aspects of health for females is a signal for reproduction.  However, what IS pretty? What are the qualities of pretty? One of the things that researchers found is that a certain profile of a woman is considered attractive.
a. The ration of waist to hips is somewhere between .7 and.8, meaning the waist should be around 70 or 80% of what the hips are. (Hour-glass figure) …Not really the Barbie doll figure, but has some curve to it.  *This shows a hormonal balance in a female. The ratio of male to female hormone balance is an indicator to the fertility of a female…the closer it is to 70 to 80 percent, the better.
b. Researchers tried to create the optimal face that would be rated as the most beautiful from a male standpoint.
*jaw, eyes, lips and skin are all important in different ways.
*Jaw , round, soft etc. is more beautiful. Square and angled is no viewed as beautiful
*Lips, should be full and red, thin lips are less beautiful.
*Eyes, larger and rounder eyes are more beautiful
*Symmetry of the face is important
*Skin, must be smooth, clear and uniform.
c. Jaw line and lips are affected by hormones. Testosterone tends to affect the development of the jaw line. The higher the level, the more square the jaw will be. Testosterone can reduce a females’ fertility.
d. Female hormones will increase the lips.
e. Large eyes tend to make a female “look” younger. Eyes of a newborn are usually larger than adult eyes. This affects youth which attracts males.
f. Clear skin is essential. Problems with skin are linked to parasites in the past. (Hunter/Gather). Clear skin is an indicator (to ancestors’ of good immune system and good health.
 *These are all related to fertility in the female. It is not because these traits are inherited.
1. The importance of a mate marrying a virgin varies across cultures. However, across most cultures, the males, more than the females, considered being chased important. Males thought it was more important than females. *This is because of paternity certainty.
Males are attracted to youth and beauty which increases the possibility of reproduction.
*A big problem for males (biggest evolutionary loser) is one that invests in offspring that he does not realize is his. In Sweden, neither male nor female are too concerned in chastity because the government takes care of the offspring, so it doesn’t matter.
1. AGE: Females tend to want males that are older than they are. They want to offload as much of the investment burden as possible. This allows the female to produce more offspring. *The females need older mates because they have had more time to gather resources and are more stable than younger males.
a. Resource holding and status…this is how many resources he has and where he stands in the community. As male ages, these aspects tend to go up. The woman will not have to work as hard.
2. FINANCIAL ATTRACTIONS: Females find this very important. What are the prospects of future financial prospects in the mate? The difference is that females find this much more important than males. *Women want to be assured that their offspring will be taken care of.