User:Djmoq3/sandbox

Article Evaluation on the Article "Dog Behavior"
The article that I have choose to evaluate is "Dog Behavior". After reading the article I can say that overall it is very well written.

First off, everything that I read in the article was relevant to the article topic. Some background information like a dogs intelligence and abilities were also included within the article so that you had the background information necessary to understand why some behaviours occur. This in my opinion was nice as it did not go into deep detail but linked to another article that would.

The article was also neutral, didn't seem to have any bias or slanted viewpoints. The citations and references that I checked all linked to the corresponding page that it was referring to, which is an indication of a good article.

One thing I did notice was there was no information regarding Behaviour to genetics, and how specific dog breeds have different temperaments which I thought could have been an important concept to bring to the table.

Winner and Loser Effects Ideas

 * Definition of Winner and Loser Effects
 * Sections referring directly to Winner Effects and another on Loser Effects
 * Examples of both Winner and Loser Effects
 * Citations that prove the legitimacy of the definitions and examples
 * Instances where Winner and Loser effects are seen in a single species, instances where Winner effect is seen only, and instances where Loser effect is only seen.
 * Fitness benefits, or underlying causes of Winner/Loser effect.

Winner and Loser Effects
The winner and loser effect is an aggression phenomenon where the winner effect is the increased probability that an animal will win future aggressive interactions after experiencing previous wins, while the loser effect by definition is the increased probability that an animal will lose future aggressive interactions after experiencing previous losses. Overall these effects can either increase or decrease an animals aggressive behaviour, depending on what effect affects the species of concern. Animals such as Agkistrodon contortrix, Rivulus marmoratus, and the Blue-footed booby show either both or one of these effects.

The affects of winner and loser effects help develop and structure hierarchies in nature and is used to support the game theory model of aggression.

Causation
A theory underlying the causation of the winner and loser effect deals with an animals perception on its own resource holding potential. Essentially if an animal perceives that it has high resource holding potential then it considers itself to be a dominant member of an intraspecific community. If an animal perceives that it has a low resource holding potential then it considers itself to be a less dominant member. This perception of resource holding potential is further enhanced or disrupted when aggressive challenges arise. If an animal wins an encounter then its perception of its own resource holding potential increases, just as if an animal loses, its perception of its resource holding potential decreases. Animals, regardless of size, with a higher perception of resource holding potential are more likely to initiate aggressive behaviour to maintain their dominance within a community. Overall if there is a large difference between the perception of two fighting animals resource holding potential, the animal with the highest perception of its resource holding potential has a higher chance of winning the encounter. Based on this theory an animal who assumes a high resource holding potential is likely to be a dominant/aggressive member while an animal who assumes low resource holding potential is likely to be a submissive/non-aggressive member of a community.

The reason an animal will accept its dominant or submissive position in a hierarchy is because of the game theory model of aggression. Based off the Hawk and Dove game, being a Hawk and Dove can be beneficial depending on the fitness associated with the trait. Game theory discusses a frequency-dependent model where both traits (aggressive vs submissive) can exist when the frequency of each meets an evolutionary stable strategy (ESS).

Hormonal stimulation
In some animals winner and loser effects have been shown to cause hormonal differences in blood plasma. Hormones like corticosterone are found to be higher in animals experiencing loser effects then those experience winner effects. Corticosterone is a stress hormone and is likely to be due to the implications of a loss in animals experiencing the loser effect. Some researchers even suggest that this increased level of corticosterone caused by the loser effect inhibits regions of the brain involved in learning and memory, but no formal literature has supported this hypothesis. An example of this increase in corticosterone following a lost is seen in the copperhead snakes.

Testosterone is another compound that whose concentration within the body are effected by winner and loser effects. Research done in humans show that after completing a competitive task against another team, the winning team's testosterone goes up, while the losing team's testosterone goes down. It also showed in a group setting that the team member who was the top-scoring player or did the most work received the highest boost in testosterone.

Importance of previous experience
Winner and loser effects are driven by an organisms previous experiences, typically in an aggressive context. The most recent fighting experience has the greatest effect on the organism, as testing done on Rivulus marmoratus showed individuals who had won there last 2 encounters (WW) had a higher probability of winning their next encounter then that of a fish who has won their last encounter but lost the one before that (LW). The literature also showed that encounters that happened two times before an aggressive event can effect the strength of the winner or loser effect. This was shown as species who won their last fight, but lost the one before that (LW), had a higher probability of winning their next fight then that of a fish that lost their last encounter but won the interaction before that (WL).

Hierarchy formation
Winner and loser effects also can also be attributed to the formation of hierarchies. A study done onXiphophorus helleri, also known as the green swordtail had shown that individuals who won were more likely to assume alpha or higher ranked positions in a hierarchy, while individuals who loss were more likely to assume omega or lower ranked positions in a hierarchy. Neutral individuals who have little experience with aggressive interactions fall in an intermediate position between winners and losers forming the Winner-Neutral-Loser (W-N-L) hierarchy.

Loser effects in copperhead snakes
Copperhead snakes rely on aggressive behaviours to fight for a perspective mate. Since aggressive behaviours in this species are selected for reproduction, winner and loser effects could have an effect on these aggressive behaviours and therefore the animals reproductive success. Male Copperhead Snakes, who have not had an aggressive interaction in months, when put in a situation to fight for a female is likely to win an encounter on the basis that his body size is larger then that of the other fighter.

When copperhead snakes are tested to see if winner effects affect their ability to win an encounter it was found that there was no winner effect. This was attributed to winners to always accept challenges from other males (even if larger), and were found to be more excitable because of this. This indicated that previous experience in winners does not increase their ability to reproduce as they are just as likely to lose a fight if a snake of larger size challenges them.

Copperhead snakes were also tested to see if loser effects were present. This was done by first placing two neutral snakes of about the same size in an arena, and then placing a one time loser snake against a neutral snake so that the results could be compared. It was found that loser effects were present as snakes who had lost previous encounters were more likely to lose again. The losing effect in the copperhead snake is so strong that even in encounters were the loser snake was 10% larger, they would always lose if they had more then one previous loss.

Winner and loser effects in blue-footed boobies
Blue-footed boobies show a frequency dependent dominant-submissive behavioural strategy. In these birds, the nestlings develop one of the following strategies, either dominant or submissive. If first born chicks showed aggression early on towards its siblings then it likely became a dominant member, while if the chick was non-aggressive early on, then it likely adopted the submissive strategy. Winner and loser effects are seen in this species due to this behavioural strategy.

Winner effects were shown when established dominant chicks were placed against non-experienced chicks in a study by Drummond. Dominant chicks were seen to be more likely to win an aggressive encounter with a non-experienced chick, even when the non-experienced chick was larger then the dominant chick. This was attributed to established dominant chicks being 6x more aggressive then non-experienced chicks due to having previous wins.

Loser effects were shown when established submissive chicks were placed against non-experienced chicks in a study by Drummond. Submissive chicks were seen to be less likely to win an aggressive encounter with a non-experienced chick, even when the non-expereienced chick was smaller then the submissive chick. This was attributed to established submissive chicks being 7x less aggressive then non-expereinced chicks due to having previous losses.