IMRAD (introduction, methods, results and discussion)

Analysis on an IMRAD journal article about nature vs. nurture in Grizzly Bears

Analytic Summary of “Nature vs. Nurture: Evidence for Social Learning of Conflict Behaviour in Grizzly Bears,” by Andrea T. Morehouse, Tabitha A. Graves, Nate Mikle, and Mark S. Boyce

Introduction

The article introduces the concept of nature vs. nurture and explains how studies have been conclusive that a blend between the environment and one’s DNA impact people’s actions. The authors state that depending on the behavior, it can be caused by nature or nurture or a mixture of both. They also present the idea of social learning, learning from watching others and mirroring the skills and mannerism they do. The authors inform the readers that after 2—3 years, cubs are old enough to leave their mothers, but during these early years propose that social learning may occur. Bears tend to have higher rates of conflict when they crossover with human settlements. In order for bears and humans to share resources and space, it is important to learn how bears develop aggressive tendencies. If the social learning theory is applicable to bears, then the current management of bears needs to change because it is enforcing conflict behaviors. For example, mother bears that have had an instance of aggressive conduct will be moved alongside their cub within the same management area as opposed to adult male bears who will be relocated. Since cubs stay with the mother for the first years of their lives, mothers with negative behaviors could be reinforcing this trait into the cub. The researches test whether conflict behavior is hereditary and/or if it is a learned demeanor (Morehouse, et al., 2016).

Methods

The experimenters took DNA samples from grizzly bears to classify grizzly bears (over other types), individual identity (to determine bears and their offspring relation) and gender. It was presumed that if a female bear and her offspring were spotted together that it was due to the mother migrating with her cub, thus the cub could still be learning from the mom. They also measured conflict behaviors, defined as an incident in which the bear caused destruction to property, stole human food, or murdered or tried to harm pets or farm animals. During these incidents, hair samples were collected or were left behind and subsequently tested to connect the bear to the issue, deeming it a bear with conflict behavior. They then compared the offspring’s conflict with the extent of parental behavioral conflict. If conflict behavior is heritable, then conflict behaviors should be reflected in both parent bears and cubs and if parent bears do not have any conflict behaviors, the cub should also not exhibit any of these negative encounters. If conflict behavior is merely due to social learning, then there should be significance between mom’s conflict behaviors and the cubs conduct occurrences, but not between the father and the cubs (since they do not help raise the cub (Morehouse, et al., 2016)).

Results

The researchers found that 30.3% of cubs were considered to have conflict behaviors, found in cubs from mother-cub relationships. This number comes from the cub alone regardless of the mother’s conflict behaviors. For relationships between father and cub, 28.6% of cubs were assessed as having conflict behaviors, regardless of the father’s conflict behaviors. The researchers then determined and included mother and fathers conflict behaviors in relation to the cubs; they discovered that cubs were not more prone to have conflict behaviors if the father had conflict behaviors or did not have conflict behaviors; however, if the mothers were reckoned as having conflict incidents, the cub was more likely to have conflict behaviors, about 62.5% of the time (Morehouse, et al., 2016).

Discussion

The results indicate that social learning, the nurture perspective, is taking place amongst grizzly bears. They provide no evidence that there is genetic contribution in terms of conduct behaviors. Although this does not determine that there is no contribution of DNA to this characteristic, the study provided no support for this theory. They were also confident they had marginal to no errors. The researchers had a restriction of a small sample size because there were not too many cubs that had adult problem bears, which may give the study less reliability. However, they claim that this particular study includes more verification of social learning in bears than had been done before. This study is applicable to the real world because if bears have an instance of misdemeanor, then the bear should be removed if caring for a cub, in order to not influence its cub negatively. However, the regulations currently in place call for first time offense mother bears to stay with the cub within the same area. To solve the problem with the protocols in place, they propose better managements on bear’s territories by disposing of items or securing them if they attract bears. After these measures are in place, other techniques can be used to continue keeping conflict away from bears. This could entail aversive conditioning, implementing unpleasant actions when an unpleasant behavior happens to reduce the chance of the behavior reoccurring. Overall, they propose implementing preventative measures to avoid conflict behaviors and if they do occur then eradicate the basis of the conflict. The final option, if all else fails to control the negative behavior, is to kill the difficult female bears (Morehouse, et al., 2016).

Article Analysis

Is the topic of the paper somewhat original?

The topic of conflict behaviors has not been overly studied, which makes it somewhat original. The authors add additional elements to make it unique, such as testing the theory on grizzly bears, over humans that is. They also focus on the topic of conflict behavior instead of concentrating on many traits. The authors discuss nature and nurture, but do so in a way that does not sound repetitive. They give enough background where an individual can understand the study, but do not overdue it. They also add their own ideas, hypotheses and conclusions to the existing research.

What was the aim of the study? What hypothesis did the researchers test? Are the conclusions reached (assuming they are valid) important to you and others (explain)?

The aim of the study was to discover if nature or nurture or both have an impact on whether grizzly bears choose to engage in conduct behaviors or not. The authors stated that they were testing the effects of both nature and nurture, but did not specify which they believed would be more causal. The conclusions provide solutions to decreasing bear conflicts which is important to people because part of the conflict behaviors involve humans, whether it be physical violence or stealing food it is impacting humans when human and bear's habitats overlaps. In order to live amongst each other, less destructive incidences would be beneficial (Morehouse, et al., 2016).

Do the Results section and the Methods section match?

The results match the methods section because the authors directly tested what they wanted to discover. They then reported what they found based upon the data they gathered during their procedure.

Are both P values and confidence intervals reported?

The p-values are reported in the study, even when they report insignificant results. They reported a 0.05 p-value for cubs displaying conflict behavior when mother bears do and a p-value of 0.92 for cubs exhibiting conflict behavior when father bears do. They also report the p-values (all above 0.05) when concluding there is no proof that negative incidents are linked to sex genes. Confidence intervals are not mentioned in the article (Morehouse, et al., 2016).

Were the outcome measures (end points) appropriate?

The conclusions were appropriate. The researchers made a hypothesis, conducted an experiment to test their theory and made applicable conclusions based off concrete data.

Are the results consistent with those of other studies?

The results are inconsistent with Galton’s (one of the first to study behavior genetics) beliefs. He thought that acts of misconduct were hereditary. However, after his proposition more research was conducted and the general consensus is that behaviors result from both nature and nurture. This is consistent with research in that a particular behavior can just be the result of one of these and not both. However, inconsistent with the finding that a behavioral choice is the outcome of both the influence nature and nurture simultaneously (Morehouse, et al., 2016).

Have the authors discussed possible limitations of the study?

The authors did discuss possible limitations, however they dismissed most of them. For example, they explain that there may have been small faults in assignments, but then they are firm that their chosen procedures decreases the chance of errors. They also mention their small sample size, but affirm that their study has evidence of the theory, despite this limitation (Morehouse, et al., 2016).

References

Morehouse, A. T., Graves, T. A., Mikle, N., & Boyce, M. S. (2016). Nature vs. nurture: Evidence for social learning of conflict behaviour in grizzly bears. PLoS One, 11(11) doi:http://dx.doi.org.proxy.library.ucsb.edu:2048/10.1371/journal.pone.0165425

Grizzly Bear. Wix [Image]