Animal Behavior - Biology 4200/5430 |
Bowling Green State University, Fall 2009 |
Discussion and Pre-Lab Preparation:
Apply the scientific method to a simple question and work through the stages of the process in a consistent fashion. Assemble in small groups (3 max) to develop a complete experimental design. Choose from the following list of variable pairs and ask a question that tests whether a relationship exists.
Towards this goal (1) phrase a concise question that can be addressed with an experiment; (2) formulate hypotheses that cover the possible outcomes; (3) make predictions from the hypotheses; (4) identify the particular measures that are needed to test these predictions; (5) choose suitable recording methods for these measures; (6) collect sufficient data; (7) analyze the data; (8) formulate your conclusion
The goal is to collect replicated observations of the behavior of your fellow students in order to become familiar with the behavior in question, then to chracterize it, and finally to examine consistency among answers. It is usually neither feasible nor necessary to reccord all behaviors of all individuals of interest all the time. A variety of sampling methods can be used to obtain a partial record that still provides us with a valid picture of the behavior in question. In most instances, behaviors can either be classified as short events (e.g. lunging at an opponent) or states lasting an appreciable time (e.g. a threat display). We can summarize the occurrence of both with counts or frequencies, while the latter can further be characterized with regard to their duration.
Students form groups of 3 each and apply a unique label on their shirt. Within your group define behaviors of interest and choose an observation individual or group. Depending on your specific question, plan a strategy with which to gather behavioral data, using observations of as many animals as possible, watching every animal for a short period, or focusing on different behaviors irrespective of the individual. Choose sampling method e.g. focal individual, scan sampling etc. Choose recording method e.g. start/end, occurrence in time period x. Select a 15 minute observation period, Whenever you observe an individual you alter behavior therefore be sneaky!
1. Ad libitum sampling, often abbreviated as ad lib, records as much information as possible. It is informal, non-systematic, and often used in field notes. Ad lib sampling may sound thorough, but because the observer can never keep track of everything that is going on, the results of these observations will always be biased by the behaviors, individuals, or situations that most attract the observer's attention. It is therefore hard to derive reliable, precise and quantitative information based on these observations. Its main value is in research planning, and in studying rare but fairly obvious behaviors.
2. Focal animal sampling. Here, all occurrences of specified actions of one individual are recorded during a predetermined sample period (e.g., one hour). The observer also records the length of the sample period, and the amount of time the focal animal is in view ("time in"). These method can provide unbiased data relevant to a wide variety of questions, particularly if animals remain in the field of view.
3. All occurrence sampling. The observer focuses on a particular behavior rather than a particular individual. For example, one might count the number of alarm calls given in a group of vervet monkeys. This is a useful method for providing the rate of occurrence of a behavior (# occurrences per unit time) or for studying the synchrony of behaviors within a group. The behavior under study should be obvious to the observer, and not so frequent that recording becomes impossible.
4. Instantaneous or scan sampling. An animal's activities are recorded at preselected moments (e.g., every 30 seconds). It is a sample of states (you are unlikely to catch an animal "in the act" of doing a behavior classified as an event), and is used to study the percent of time spent in a certain activity. If the behaviors of all members of a group are surveyed within a short period of time, we call it scan sampling. This provides data on the distribution of behavioral states in a group. Instantaneous or scan sampling is best done with a sample interval as short as possible, and with behaviors that are very easily identified. The behaviors should ideally be relatively long compared to the sample interval. It is an excellent method for collecting a large amount of data on a group of animals.
Compare recorders in the group to assess consistency of observations