Anyone who studies social animals in the wild (or human groups, for that matter), will soon find that some individuals threaten or attack others frequently, while others try to get out of the way or signal their submission in response to aggression. Observers tally the outcome of such aggressive interactions between any given two individuals (or ‘dyads’) and try to deduce the rank hierarchy from such winner-loser matrices. One drawback of this approach is that all temporal information is lost.
Imagine Royal, a baboon, dominating over Power, another baboon, 20 times, and Power dominating over Royal 20 times as well. If we just look at these data, we might think that they have the same fighting ability and similar ranks. But, if we know that Royal beat Power the first 20 of the interactions, then Power beat Royal in all further interactions, we’d come to a totally different conclusion. We’d infer that Power had toppled Royal and a rank change had taken place.
How do Rank Hierarchies Change Over Time?
One prominent method that takes the temporal dynamics of winner-loser interactions into account was originally developed to calculate the relative skill level of chess players. This method was introduced by Arpad Elo and is hence known as Elo-Rating. Elo-Rating has also been applied to rate the relative skills in a variety of competitive fields, including Major League Baseball, video games, and Scrabble. Continue reading →
This issue contains two Applications articles and one Open Access article. These three papers are freely available to everyone, no subscription required.
–Solo: Solo audio recorders are inexpensive, easy to construct and record audible sound continuously for around 40 days. The paper also has a video tutorial explaining how to assemble the required hardware and comes with a companion website with more information.
–The third dimension: A novel design to obtain three-dimensional data on the movements of aquatic organisms at depths of up to 140m. The set-up consists of two synchronised high-speed cameras fixed to two articulated arms and can be used for any underwater applications that require synchronized video recordings of medium- to large-sized animals.
The February issue of Methods is now online! As you may have seen already, it includes the BES cross-journal Special Feature: “Demography Beyond the Population“. There are also eight other wonderful articles to read.