Thursday, April 29, 2010

Are Humans an Exception or do We Follow all the Same Rules?

Throughout all of the research that I have done over sexual selection in humans it is clear to me that we do break a lot of the rules. Although I agree that we are an exception I don't believe that this exception means that what we do is not evolutionarily explainable. We evolved just like every other organism did, the only difference is we evolved something that many other creatures did not. That something would be our brains.

For eternity I believe that scientist will try and find hard evidence that show why we do the things that we do, but I have a strong feeling that all we will be able to do is speculate. Sometimes you just have to go by what you know, and what we know is evolution, and in particular sexual selection. If you look at sexual selection in other organisms and apply what humans do to these different observations it can be concluded that we are just as subject the effects of sexual selection as any other creature. We as humans just seem to try and make why we do what we do a challenge to figure out.

Saturday, April 24, 2010

Sex: Why We Have It






The main function/reason for having sex is reproduction so you can increase your fitness by contributing more genes to future generations. Humans differ from other animals in that they have sex for pleasure as well, and not always for reproductive purposes. Now these two reason are of pretty common knowledge. According to the article "Why Do People Have Sex?" based on research by David Buss and Cindy Meston, found on Science Daily, people have sex for many more reasons then just these two.

Buss and Meston uncovered 237 different motivations during their studies. Like we all know humans tend to be the exception to the rule when it comes to thing like sexual selection. People are the only creatures that do things for spite, and people can be spiteful during sex as well. One of the reasons that someone might be motivated to have sex with another person is to give them a sexual transmitted disease. This does not increase the fitness of either individual and it might also decrease the fitness of both individuals. If a person is trying to give someone an STD they have the possibility of gaining another STD from the person they are trying to harm. This whole spite things sounds pretty awful but people have sex for selfless reason as well.

I wouldn't necessarily call this altruism, because the other individual ultimately gains something from the experience, but it seems very close. Some people said that they had sex to tell someone thank you or to make that person feel better. People also have sex for selfish reasons as well, some people said that they had sex to get a promotion, or to become more popular.

It seems like if you can think of a type of mood people probably have sex because of that mood that they are in. People have sex because they're bored, they want exercise, they are angry with someone, they want to make up after a fight, they are sad and want to feel better, or they feel insecure and want to try and convince their partner to stay. Some people also have sex if their partner pressure them enough to do so.

It's interesting that people have found so many other ways to utilize the act of sex for reasons other than producing offspring. In the end there is always a chance that any of the times that anyone has sex whatever their motivation may be, they have the possibility of successful fertilization.

So a question to ask is, is it evolutionarily adaptive to have sex for all of these different reason? I think that the answer is yes. The more you have sex the better chance you have of producing offspring no matter how much protection you use since nothing is 100% effective.

Sunday, April 18, 2010

It's not always about what you say, but what you do.


What you don't say can be a lot more important than what you actually verbalize. When people try to attract someone of the opposite sex sometimes the physical cues are what actually bring two people together to start a conversation. In an article by Nadine Hugill, Bernhard Fink, and Nick Neave entitled "The Role of Human Body Movements in Mate Selection", the importance of the way that we move in relation to Mate selection is discussed.

One part of this article discusses a topic that has been touched on previously and that is the topic of dance and how it correlates to sexual selection. As we know dance can be a window to how strong and how healthy a potential mate may be. I won't spend any time on this point since it has been previously discussed.

One of the experiments that was discussed in this article was using Point Light Displays where 10 to 12 points lights are placed on major joints in the body to show body movement without actually getting to see the body. For the overwhelming majority of the time men and women were able to differentiate between who was male and who was female from just the Point Light Displays. They were also able to differentiate age, weight, and even who they were if they knew the person well enough. This experiment tells us a lot about what people can discover about others just from the way they move. The way that someone walks can show what kind of emotional condition they are in as well as other personalities traits that the person might potentially hold. From pictures as well as videos that were shown to male participates showed that men overall preferred women with a higher hip to waist ratio because of the walking motion of the hips in contrast with the waist. Also in general the most tell difference between men and women it the hip to shoulder ratio. Men usually have wider shoulders while women have wider hips.

None verbal communication is very important to meeting a person for the first time. When you meet someone new you can't be sure of what their intentions are so it is important to look at what their body is saying and not necessarily what they are actually verbalizing. It has been reported that when a woman is trying to interest a man that there are certain techniques that have been found to be consistent. Women use certain postures, and usually use more eye contact, as well as walk differently. Men on a subconscious and conscious level find these behaviors attractive and are more likely to go and talk to that particular woman.

It is very interesting to read this article and think about how women go about trying to attract men though dancing and other visual cues when it most species it is the male that does all of the dancing and wooing. After reading over this information it made me think about how people always say that first impressions are really important to get a relationship started. Now I can see that first impression start far earlier than the first hello.

This video describes how much can be read from body language from neutral interest to very interested.

Tuesday, April 13, 2010

Your Kiss is on My Evaluation List


Kissing seems like a harmless enough practice. On the surface it just looks like a romantic gesture, but kissing is deeper than that. When kissing occurs especially if it is an open mouth kiss chemicals and hormones are exchanged that can tell a person a lot about the person that they are kissing whether they consciously realize it or not. In a study by Susan M. Hughes, Marissa A. Harrison, and Gordon G. Gallup a deeper assessment of kissing was conducted. The article is entitled “Sex Difference in Romantic Kissing among College Students: An Evolutionary Perspective”. In this article the importance of kissing to each member of the sexes is evaluated, and what exactly it is that kissing can convey to the opposite sex.


In this study a total of 1,041 college students, mainly in the age bracket of 18-24, were giving a survey to fill out in their psychology class. A smaller percentage of the study group was 25 or older. The individuals who reported never having kissed someone romantically were left out of the study so the data comes from individuals who have had romantic kissing experiences. Also only people who preferred only or mostly kissing members of the opposite sex were included because the study was “examining opposite sex relations as it relates to mating strategies”.


When people kiss many different hormones and chemicals are exchanged. When people kiss olfactory cues are sent to the brain, and there also is a possibility for the transfer of sebum (the oils from our skin) from the contact of the skin surfaces around the mouth. So when open mouth kissing occurs there can be an exchange of sebum there that would carry hormonal and pheromone messages. Also the taste of some ones mouth as well as the smell of their breath can be an indicator of health problems that may not be readily noticeable without kissing. Also men may like to swap more spit than women do, overall, because there are hormones and proteins that can be introduced via the saliva that can make a woman more sexually receptive. For example the mucus membrane in the mouth is permeable to testosterone.


In the study it was shown that in general females place more importance on kissing then males do. This may be because women’s chemoreceptors are more sensitive than those of men. This also might be why men are shown to prefer wetter kisses because it may take them longer and they may need more of whatever the chemical may be to make any subconscious assessment about their partner. Men place much less importance on kissing when it comes to sexual relations as well. More men don’t find it necessary to kiss before having sex with someone, and they also take kissing people they are in short term relationships with lighter than women do. More men are shown to take kissing as an indicator that a woman wants to have sex with them. Woman find kissing more, overall, important to a relationship than men do, but in most cases both sexes agree that kissing is more important in long term relationships than in short-term relationships.


Women have more jealously than men do when their short term or long term partner kisses another person especially if that kiss is open mouthed. The reason that women tend to be more jealous is because females can only have so many children in their life time so they are looking for a stabile and a good mate. Men have the opportunity to contribute many more genes to future generations than women do. One way that a man can try and resolve a fight over such issues as jealousy is yet again kissing. It is shown in the studies that one way that men try to reconcile a fight is by kissing. Whether or not this works every time is another story.


Women are also more likely not to have sex with someone if they are a bad kisser than men are. Not only can the way that a person kisses contribute to whether or not their partner likes them, there are also many different other variables that are taken into account before some people will even consider kissing. Whether or not a man has good teeth was very important in this study as to if the woman would kiss the man. Men did not find teeth as much as an important factor as women but they did find that the overall attractiveness of the woman’s face, and also her body was more important.


So kissing can tell us a whole lot about a person without even having to ask them, it can be used to encourage sexual relations, to make up after a fight, and most importantly kissing is yet another interesting facet of sexual selection in humans.

Side note: Bonobos and common chimpanzees, which are closely genetically related to humans, also use kissing in lots of the same ways that humans do.



Sunday, April 4, 2010

What’s height got to do with it?



Ever hear a woman say she’s looking for Mr. Tall, dark, and handsome? Well she might actually be doing just that. In an article by Gayle Brewer entitled, “Height, Relationship Satisfaction, Jealousy, and Mate Retention” the relative attractiveness of different heights to women are investigated.

In this study it is discussed that women, in general prefer tall men because of the evolutionary advantages that being tall possesses. The taller a man is the greater the quantity of testosterone is present in his body. The greater the height of a man may indicate a better ability to protect or provide, which in turn is a cue to a woman that a taller man will be able to pass on these qualities to her children.

In a study of 98 heterosexual males it was shown that men that were taller had less jealousy in their relationships, and were over all more satisfied with their relationships. That’s not to say that taller men are not prone to be just as jealous as shorter men, they are just jealous at different instances for different reasons. Tall men and short men also deal with their jealously differently.

Taller men tend to ward off their chances of jealously by practicing “mate retention” behaviors. They are more likely to make sure that almost all of their mate’s time is spent with them instead of out with friends where there could be other males that their partner could find more attractive. Taller men are also more likely to be watchful of their partner to make sure that they are not talking with someone of the opposite sex behind their back. The reason that taller men use these strategies is because they find themselves to be good mate choices and don’t view this potentially negative behavior as having any serious consequences on the relationship since they don’t feel they have much competition.

Since shorter men often feel more jealousy then taller men they are more apt to try and keep their partner by showing more care and affection. They are more likely to try and convince their partner that they don’t need to go and look for some taller man with more testosterone because they are a more stable partner that can provide and give them the affection that they need.

After reading this article it started me thinking about the whole idea behind why so many women prefer the “bad guy” to the “good guy” It seems like the taller men that have more testosterone have more of the bad guy qualities when they are practicing mate retention behaviors, like watching their partner, and keeping them from spending time with other people besides themselves. Shorter men seem to exude the good guy qualities with their mate retention behaviors when they do more caring and affectionate things to try and maintain their relationships.

*New word: Cuckold- The husband of an unfaithful wife.

Example: The shorter man was made a cuckold when his wife cheated on him with a taller man.

Sunday, March 28, 2010

You've Got a Great Personality!



Mate selection criteria: A trait desirability assessment study of sex differences in Serbia

Have you have heard the saying that if someone has a great personality than it’s code for they are interesting but not attractive? Well, I’m ready to talk about why that’s just not true, and what people really find the most attractive, and important in choosing a mate.


There are a multitude of traits that people take into consideration when choosing a mate. From watching movies, and looking at magazine advertisements you would think that the most important trait to most individuals would be physical attractiveness. A study by Bojan Todosijević, Snežana Ljubinković, and Aleksandra Arančić entitled Mate selection criteria: A trait desirability assessment study of sex differences in Serbia” shows that in a study of 127 individuals that physical attractiveness comes in at number 22 on a list of 60 different traits.


The study shows that the top ten traits that people look for in a mate are, in order from most importance; sincerity, faithfulness, tenderness, reliability, communicative, passion, carefulness, amusing, love for children, and self-confidence. None of these traits has anything to do with any sort of physical feature.


In this article it talks about how it is most popularly believed that men usually look for physical attractiveness in a woman while women look more for great personality characteristics and are not as interested in physical attractiveness. This also proves to be somewhat of a misconception. Women find strength and thinness as factors when deciding who they choose as a mate. These qualities can be attributed back to previous blog entries about the qualities that women looked for in the past that could reveal that the particular man was more capable of survival.


When it comes to negative traits it discusses which traits are the most negative and who tolerates these traits more readily. Some particular traits that men are able to tolerate better than women are the traits fearfulness, self-pity, and aggressiveness. Women might not be able to accept these qualities are readily as men can because these traits are not conventional masculine. The traits that are seen as the 10 least desirable are from less undesirable to more undesirable; shyness, overweight, introversion, spoilt brat, self-pity, aggressiveness, fearfulness, insecurity, selfishness, and conceitedness.


One of the most interesting bits of information that I found was the fact that in the past women were less involved in society in the area of the work force and in status than men. You would think that women would be able to choose mates with statuses lower than themselves since many women now have very high paying jobs and are capable of supporting not only themselves but others as well. Women are still shown to prefer higher status mates even when they are at a very high status themselves when it comes to income.


In the end what people are really looking for in a mate does have a lot to do with personality but it’s really a good balance between physical attractiveness, status, and specific personality traits. It is shown in this study that want people want to someone that they can grow with and having a satisfying relationship. The comparison that I like the best is that a relationship should be like peanut butter and jelly you can't have one with out the other.




Sunday, March 21, 2010

You're So Vain, You'll Probably Choose a Mate That's Just Like You


Humans choose their mates based on many different variables. One of those variables is likeness. To be more specific I am referring to physical likeness. After reading an article by Liliana Alvarez, about an experiment done to test the theory that we are attracted to others like ourselves, I found a lot of insightful information. The article is titled "Narcissism guides mate selection: Humans mate assortatively, as revealed by facial resemblance, following an algorithm of 'self seeking like'."

My first thought was why would we want to find a mate that looks similar to ourselves? I thought that the theory might not have been very stable, because if we looked for others physically similar to ourselves than inbreeding would probably occur since close and even distant families members would theoretically resemble each other the most. Through reading this article I discovered that our instincts lead us away from both out-breeding and in-breeding since both can have deleterious effects. Too much out-breeding and in-breeding can both lead to too much homogenization which will lead to a decrease in variability. This is probably why we choose mates who look similar but have no linkable relation to ourselves.

In the experiment documented by Alvarez 36 randomly chosen couples were compared and the similarities between the six couples pictured is quite surprising. This picture can be found in the article at this link on page 6.

Different individuals were then asked to identify different things such as which male and female look most closely related, and which male and female look like they are a couple. The results of the experiment show that people matched the couples that looked the most similar to each other in both situations.

Another reason, that was stated in the article, as to why we choose to mate with people who look similar to ourselves, is the fear of rejection. People who think that they are less attractive than another individual have less of a chance of asking that individual on a date because they fear the idea of being rejected by a person that they believe to be very attractive.

People were also asked to rate the individuals pictures on how attractive they were. Another result was that people usually ended up pairing the people they considered most attractive with each other, and so on down the line to the people that they considered the least attractive to themselves. These pairings of individuals on this basis also have relatively accurate results.

So where does this like of physical similarity stem from? According to Alvarez it stems from our parents. A process called imprinting is occurring when we are small children, and it is the process of formulating what we consider to be attractive qualities in our minds. As it states in this article there is no way to define what is attractive and what is beautiful. That is decided by the individual, but as we have discussed that idea of beauty comes from what we imprint as children, which just happens to be our parents who are very physically similar to ourselves.

All of this boils down to one of the assumptions of Evolution, non-random mating. Because if mating were random than people would just mate with anyone without any criteria necessary. Non-random mating is inherently assortative. We all have specific things that we like and that we don't like and we sort through people based on these criteria, as to who we would like to mate with.

Physical likeness is just one piece of a larger picture of why we choose the people that we choose as our partners, but it is also a very important one when it comes down to the instinctual pressure to avoid excessive out-breeding and in-breeding. There is a saying that came to mind while I was reading this article, "you must first learn to love yourself before you love another", and after reading the article I concluded that once you love yourself you'll want to love someone just like you.