Evolutionary Psychology #2
Why Humans love Spices, Hunter-Gatherer Sex Differences, Food Selection in rats
Why Humans Love Spices
In the middle ages, spice was one of the main things traded by the Asians and Europeans. Christopher Columbus and Marco Polo both went on their voyages in search of spice routes. Humans have always loved spices. However, evidence suggests that we might have an attraction to spices that goes beyond taste.
Spices can kill or inhibit the growth of microorganisms and prevent the production of toxins in the foods we eat — (Sherman & Flaxman, 2001)
This property of spices will have saved countless human lives. It is no coincidence how the countries that embrace spices the most, all have hot climates. The food goes off faster than in cold climates, making spices all the more important. The spices that are the best at killing bacteria are:
- Onion
- Garlic
- Allspice
- Oregano
Not a bad list.
Sex Differences in Spatial Abilities
It is estimated that humans have been hunter-gatherers for over 90% of their existence. The general idea is that humans have two sources of food; hunting for meat, and gathering for fruit/veg. Generally, in the course of history it has been the men hunting, and the women gathering. Therefore one could expect that each sex would have picked up evolutionary traits that would aid them with their respective duties. This has been proven to be the case. The evidence is based on a study comparing spacial ability differences between the sexes, which spanned data from over 40 countries. The findings were as follows.
Men
Studies spanning the last half century have shown a male advantage on spatial tests, with three-dimensional mental rotations (3DMR) yielding the largest and most reliable differences (Silverman, Choi & Peters, 2007)
High spacial ability scores have been linked with throwing accuracy. This would have helped with spear throwing. Studies also found a positive relationship between 3DMR and wayfinding by orientation. This involves travelling somewhere unknown, and then being able to get back without there being any major landmarks in between. This was an essential skill for hunters. They would often need to patiently follow an animal along an unknown trail. So it shouldn’t come a surprise that men are better at mazes.
Interestingly enough, it has also been found that male rodents are better at maze-learning tasks than their female counterparts.
Women
Being a gatherer posed a different set of challenges.
Successful gathering would have entailed locating edible plants within diverse configurations of vegetation and then finding them again in ensuing growing seasons. This, in turn, would have required the capacity to rapidly learn and remember the contents of object arrays and the relationships of objects to one another within these arrays. (Silverman, Choi & Peters, 2007)
As a result, women outperform men in spacial tasks that involve remembering the locations of objects. During a hunt, the hunter’s visual focus is solely on the prey, whereas during gathering the incoming visual stimuli are more varied. Gatherers needed to learn quickly which objects (fruit/veg) were suitable or not. In fact, females have a larger visual fields than men. This means they can ‘see farther out on the periphery while fixating on a central point.’
If you would like to know more about the hunter-gatherer theory of sex differences in spacial abilities, this study is worth reading.
Food Selection in Rats
Rats adaptively adjust their eating behavior in response to at least three internal states: deficits in water, calories, and salt (Rozin & Schull, 1988)
So if a rat has low body salt levels, its tasting wants are going to gear more toward salty food. Alternatively if its calorie count is low, it’ll probably go for that pasta you left in the cupboard. Rats are actually very sceptical when they approach new, unknown food sources. They first sample the food, and in small quantities. They then assess whether or not it makes them sick. In the cases where the rodent consumes poison, the instinctual decision to take a small bite could save their life.
