Ever wonder why people are more likely to help their relatives than complete strangers? Social behavior can help explain this and other actions. Let's look at the cost of certain behaviors.
Certain behaviors help define social groups. These can be broken up into four main types: altruistic, which benefit the recipient at a cost to the performer, selfish, which benefit the performer but cost the recipient, cooperative, which benefit both the performer and the recipient and spiteful, which cost both the performer and the recipient. In this lesson, we will mainly focus on altruism, but let's first look at what defines a social group as well as the costs and benefits associated with living in a group.
Social Groups and Social Behavior
Apes form social groups to hunt for food together
When you think of social group, you most likely think of your group of friends. You all may have similar interests, live in the same general area or maybe work at the same office. Other animals also have social groups which have some of the same characteristics as your social group. For example, apes living in a social group are located in the same area and participate in activities together. While you may go out to eat with friends, apes may hunt or look for food together.
A general definition of a social group is a group of animals living together in order to increase survival and reproductive success.
Within a social group, you are likely to see certain social behaviors. These are behaviors that come about when individuals cooperate with other individuals. These behaviors are often specific to a social group. For example, you and your group of friends may have certain words that you use when around each other. Oddly enough, this can also be seen in some goats which have specific accents depending on their social groups.
There are certain aspects of living in groups that tend to help animals, but there are also some downsides. Let's first look at why living in a social group is beneficial.
Costs and Benefits
There are two main benefits seen when animals live in groups: improved hunting success and improved protection from predators. Let's look at a few examples more closely. Dolphins are known to hunt in groups. When they do this, the dolphins are able to trap a significantly larger number of fish and therefore, the survival of all members of the social group is enhanced.
This hunting can also be seen in species such as lions, which will team up when hunting large prey.
Opposite of this is the protection that a group can provide against a predator. It can be very challenging for a sole predator to isolate one individual from a large group as his prey. We can use the example of a dolphin again. If a dolphin tries to hunt on its own, it is very challenging for the dolphin to isolate one fish in a very large school. Therefore, the group living of the fish helps all members of that group survive.
By hunting as a group, dolphins can trap a larger amount of fish
However, it is important to keep in mind that there are also costs to living in groups. The two main costs of living in a group are: an increase in competition and an increase in the spread of diseases. The increase in competition can be seen when considering food and mates. When a large group of animals lives together, there are more mouths to feed which means more competition for the best food. For example, if you have a large pizza all to yourself, there is no competition. However, when a few of your hungry friends stop by, there is definitely competition for the pizza.
The spread of diseases also increases when animals live in a close knit group. When animals live individually, it is hard for an illness to spread from one individual to another. However, if one individual in a group is ill, it is very easy for the illness to spread to others. This can again be seen in your social group. If one of your friends catches a cold, it is likely that the other people in your group will also soon come down with the same illness.
Altruism and Kin Selection
Let's now relate the costs and benefits of living in social groups back to the concept of altruism. Remember that altruism is a behavior that benefits the recipient at a cost to the performer. Someone who is altruistic would put the well-being of others before himself or herself - such as what we see with a lifeguard or firefighter.
This behavior of self-sacrifice can be connected to the concept of kin selection. Kin selection is when an individual chooses to help its relatives in order to increase the survival of its traits. This can be a little tricky so let's break kin selection down a little bit. Generally, what this means is that an individual is more likely to help another individual who is more closely related. This is because the more closely related individuals are the more similar traits they have. For example, in humans, people are more likely to donate a kidney to someone to whom they are related. That is, you are more likely to give a kidney to your niece or nephew than you are to a complete stranger. This kin selection relates back to altruism because there is a cost - the loss of a kidney - to the performer, but a benefit - a new, working kidney - to the recipient.
All of these actions are associated with living in a group. Because it is beneficial for the group if more individuals survive, altruism may occur. However, individuals must consider three main items when it comes to altruism: energy cost, opportunity cost and risk cost. Energy cost concerns how much energy the individual will have to put forth to perform the action. You may often consider how much energy you want to put into a task before deciding if it is worth doing. Opportunity cost concerns what other actions the individual may miss out on by doing the task. You may consider this when you decide if it is worth staying in to study rather than going out with friends. Risk cost concerns the increased chance of being injured or killed as a result of performing the action or not. You may think about this when you decide to cross a street even though the walk sign is not yet on. Once all three aspects are taken into consideration, an individual may perform an altruistic act.
Living in social groups can have costs and benefits. While it is beneficial to hunt in groups and to avoid predators, there is an increase in competition and the spread of disease when living in groups. Altruism and kin selection often come into play in social groups. Let's look back at the kidney donation example. You are more likely to donate a kidney to someone who is closely related to you than to someone who is not related to you. This altruistic act illustrates kin selection. When deciding if you want to donate a kidney, you would also consider the energy, opportunity and risk costs. Once all of these aspects have been taken into consideration, you can decide if the costs and benefits are correctly balanced and what action would be best for your social group. Remember that social behaviors, such as altruism, govern the actions of many individuals and tend to increase the survival and reproductive rates of individuals and groups.
After watching this lesson, you should be able to:
- Define social group and explain the costs and benefits of living in one
- Define altruism and understand the three types of costs that are related to it
- Define kin selection and describe how it relates to altruism