Human culture becomes more complex by building on previously established advances. This type of societal evolution was once thought to be a feature unique to human society, but research indicates we are merely examples of a larger phenomenon.
For many organisms it is important to develop learning strategies to compete with predators. Some species learn by observing the behaviours of others, while others rely solely on personal experience. Complex discriminatory learning mechanisms involving memory and strategy were originally considered a hallmark of advanced human behavior.
A 2009 study by scientist Jeremy R. Kendal of Durham University challenged this assumption with a common fish species. Nine-spined sticklebacks are found in salt and freshwater environments worldwide. These small fish are exposed to high levels of predation in their habitat, thus pushing them to evolve. They are also the first nonhuman organism known to exhibit the allegedly human social learning strategy termed hill-climbing.
Hill-climbing is a strategy that supports the cumulative development of a population. It involves the organism’s ability to observe and appraise the tradeoffs of a strategy exhibited by another member of its species, called its conspecific, and grade those payoffs by determining the costs and benefits associated with a particular course of action. There may also be more involved considerations dictating copying behaviour regarding the payoff of its conspecific, and the organism’s dissatisfaction with its own current behavior.
Nine-spined sticklebacks show the ability to judge the quality of a feeding site based solely on the information they get from the relative feeding activity of conspecifics. They can distinguish between the kinds of social information and pick what they want to use. For example, they will preferentially draw from personal experiences as opposed to a social learning strategy. However, if they have outdated information from personal experience, they will most likely choose the newer social learning information. They conditionally choose between personal and social learning.
The researchers tested the social learning capabilities of this fish, using other fish to demonstrate a particular behaviour. The subject fish were exposed to a specific environment with a set amount of food at two feeding stations, followed by the stimulus of demonstrator fish that had different feed levels. It was found that the sticklebacks tended to employ copying behaviours more when the demonstrator’s feeding activity was higher than their previous food setting, but did not copy if the demonstrator’s payoff was less than theirs, even if all the demonstrators fed at the same patch. Moreover, the fish were found to copy more when they observed a higher rate of payoff than their own. Nine-spined stickleback used a “copy-if-better” or proportional implementation strategy in accordance with the hill-climbing method.
“The ultimate implications are in the fact that fish or other organisms that were considered to be lower or less sophisticated than us are actually capable of very sophisticated thinking. In fact, organisms with so-called small brains may have very similar methods of learning, implying that it is not necessarily size or specific kinds of brains that lead to complex thinking. Perhaps there are other mechanisms involved that would influence learning,” comments Professor Vincent Tropepe of the Department of Cell and Systems Biology at U of T.
These new findings bring into question our previously held ideas about the differences between humans and other animals. In fact, it seems as though animals with tiny brains such as these fish are capable of social learning similar to our own.
