Social Behavior: The Cost-Benefit of Altruism and Kin Selection

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Social Systems vs. Individual Fitness: The Queen/Worker Relationship

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:06 Social Groups and…
  • 1:51 Costs and Benefits
  • 3:50 Altruism and Kin Selection
  • 6:06 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Danielle Weber

Danielle teaches high school science and has an master's degree in science education.

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
altruism 1

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
altruism 2

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.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account