If you studied pictures that ancient people left on rock walls and you tried to determine their meaning, you would not detect interest in romance among the artists. 1, you would see plenty of animals with people running after them. Life for ancient people's earned to center on hunting and gathering wild foods for meals.

    In modern times, when food is available in grocery stores, finding love is more 2 in people's lives. The 3 is all around us. It is easy to prepare a list of modern stories having to do with love. An endless number of books and movies qualify as love stories in popular culture.

    Researchers are studying whether love, a highly valued emotional state, can be 4. They ask, what is love? Toothpaste companies want us to think attraction is all about clean teeth, but clean teeth go only so far. Scientists wonder how much the brain gets involved. You have probably heard that opposites attract but that 5 attract, too. One thing is certain: The truth about love is not yet set in stone.

    First Impression

    To help determine the 6 of attraction, researchers paired 164 college classmates and had them talk for 3, 6 or 10 minutes so they could get a sense of each other's individuality. Then students were asked to 7 what kind of relationship they were likely to build with their partners. After nine weeks, they reported what happened.

    As it turned out, their 8 judgments often held true. Students seemed to 9 at an early stage who would best fit into their lives.

    The 10 Knows

    Scientists have also turned to nonhumans to increase understanding of attraction. Many animals give off pheromones — natural chemicals that can be detected by, and then can produce a response in, other animals of the same species. Pheromones can signal that an animal is either ready to fight or is feeling 11 to partnerships. In contrast, humans do not seem to be as 12 as other animals at detecting such chemicals. Smell, however, does seem to play a part in human attraction. Although we may not be aware of chemicals like pheromones consciously, we give and receive loads of information through smell in every interaction with other people.

    Face Value

    Being fond of someone seems to have a number of factors, including seeing something we find attractive. Researchers had people judge faces for 13. The participants had 0.013 seconds to view each face, yet somehow they generally considered the images the same as people who had more time to study the same faces. The way we 14 attractiveness seem to be somewhat automatic.

    When shown an attractive face and then words with good or bad associations, people responded to 15 words faster after viewing an attractive face. Seeing something attractive seems to cause happy thinking.