Throughout my studies of animal communication and animal behavior, I have often wondered whether the results of field studies can be considered valid, since it would seem intuitive that the act of observing animals could significantly alter their natural behavior. For example, do birds that are being watched by researchers consider the observer to be a threat? If so, they would most definitely display more aggressive behavior than usual. To investigate this question, I read an article entitled Does watching a monkey change its behavior? by Crofoot et al. (2010).
According to the article, the issue of observer response has been a large concern among researchers for many years. To minimize the effect an observer has on their animal of study, several techniques have been utilized, many of which have proven inadequate. Possible solutions have included hiding or disguising oneself in the field, or using cameras and remote data collection methods; however these methods limit observers to a fixed location and cannot provide the detailed behavior data gained through direct observation. The most trusted and often used method to prevent observer effect is habituation. Carpenter (1934) first proposed that “with sufficient ‘neutral exposure’, animals would become accustomed to and eventually ignore human observers.”
To test the method of habituation and its validity and effectiveness in field studies, Crofoot and his team used data from an automated radiotracking system to test whether habituated capuchin monkeys altered their behavior when a human was present. In the months of July and August, Crofoot’s team captured seven capuchins belonging to four social groups and fitted them with radiocollars. For the next several months, the team tracked the activity and behavior of these capuchins remotely, without any human presence. The study animals then experienced five months of regular contact with human observers, after which they seemed fully habituated to the presence of the researchers. After this habituation period, the observers followed the capuchins throughout their habitat making behavioral observations similar to those tested using the radiotracking system, the only difference being the researchers’ presence in the field.
What Crofoot found was that after a significant period of habituation, observer presence did not significantly affect any of the behaviors investigated. However, during the period of habituation, the behavior of the monkeys was significantly different than the observations made by radiotracking prior to this period. These data show that the effects of human observers can be great, but through habituation, these effects can be significantly minimized. I found it interesting that I had never heard of habituation when studying animal behavior in the past, since it seems to be an extremely important preliminary step in order to produce experiments in which the results can be trusted.
- Amanda Grafstein
Amanda, I am really surprised that I hadn't heard of that either! It makes perfect sense. I also think people worry so much about human error that they forget to account for things like habituation. I was thinking along these lines about making ethograms. I really like how relevant this information is to what we're doing in class now.
ReplyDeleteIt certainly makes sense that researchers would want to ensure that the behavior they were observing is truly "normal" behavior for the subjects. Since this study used wild animals, I wonder how this approach would change if they were studying captive animals - in a zoo, for example, where animals are "observed" by many different people every day. How would the habituation study differ, and would there be differences between wild-born and captive-born animals?
ReplyDeletePosted by Dana Mirsky
I think this a very interesting thing that I too, have never heard of. What I'm wondering is that since the animals are becoming used to the humans, does this affect their survival later on? The monkeys used in this experiment, for example, are highly sought after in the Thai black market as pets. I feel that this could potentially lead negative behaviors in these monkeys when human poachers approach.
ReplyDeleteBaileyM0225: I agree that people probably get caught up in accounting for human error rather than trying to account for this observer response. I imagine that this is why I had never heard of habituation before. However, it certainly seems important!
ReplyDeleteDana: I think that if researchers were studying animals that were in a zoo, then the results could be considered valid, since the animals in the zoo are probaby already habituated to the presence of humans watching them. However, it could be true that they have merely adapted their natural behaviors to accomodate their new zoo environment, so the results obtained at a zoo are not necessarily correlated to how these animals would behave in the wild.
Lora: I hadn't thought about how the habituation would affect the monkey's survival later on. I imagine that it could be harmful to become habituated to humans if there are humans that are a threat to the monkeys. If poachers were to approach this group of monkeys, they may not be as quick to respond and could potentially be in more danger than they would be pre-habituation.
Do you know of any other, possibly less evolved animals that also have a lengthy habituation period where they behave very differently or is this most often seen in a monkey?
ReplyDeleteAhmed Sandakli