User:Bhavyaa Chandarana/sandbox

(new section to be added under mirror neuron section in Bird Vocalization > Learning)
make sure to link the word just above auditory feedback section "cultural interaction" to this section below:

Learning through cultural transmission
Culture in animals is usually defined to consist of socially transmitted behavior patterns ("traditions") that are characteristic of certain populations. The learned nature of bird song as well as evidence of "dialect"-like local variations have led some researchers to hypothesize the existence of avian culture.

As mentioned above, bird song's dependence on learning was studied by Thorpe, who found that chaffinches raised in isolation from their first week of life produce highly abnormal and less complex songs compared to other chaffinches. This suggested that many aspects of song development in songbirds depends on tutoring by older members of the same species. Later studies observed canary-like elements in the song of a chaffinch raised by canaries, evidencing the strong role of tutors in the learning of song by juvenile birds.

Similar chaffinch song types (categorized based on their distinct elements and their order) were observed to cluster in similar geographic areas, and this discovery led to hypotheses about "dialects" in birdsong. It has since been postulated that these song type variations are not dialects like those we found in human language. This is because not all members of a given geographic area will conform to the same song type, and also because there is no singular characteristic of a song type that differentiates it from all other types (unlike human dialects where certain words are unique to certain dialects).

Based on this evidence of learning and localized song types, researchers began to investigate the social learning of birdsong as a form of cultural transmission. The behavior patterns constituting this culture are the songs themselves, and the song types can be considered as traditions.

Dopamine circuits and cultural transmission
A recent study has shown that a dopamine circuit in zebra finches may promote social learning of bird song from tutors. Their data shows that certain brain areas in juvenile zebra finches are excited by the singing of conspecific (i.e. same-species) tutors and not by loudspeakers playing zebra finch song. Additionally, they show that dopamine released into the HVC aids in the encoding of song.

The cultural trap hypothesis
Although a significant amount of research was done on bird song during the 20th century, none was able to elucidate the evolutionary "use" behind birdsong, especially with regards to large vocal repertoires. In response, Lachlan and Slater proposed a "cultural trap" model to explain persistence of wide varieties of song. This model is in based on a concept of "filters", in which:


 * a male songbird's (i.e. singer's) filter contains the range of songs that it can develop
 * a female songbird's (i.e. receiver's) filter contains the range of songs that it finds acceptable for mate choice

In one possible situation, the population consists mainly of birds with wide filters. In this population, a male songbird with a wide filter will rarely be chosen by the few female with narrow filters (as the male's song is unlikely to fall within a narrower filter). This female will now have a relatively small choice of males to mate with, and so the genetic basis of the female's narrow filter would not persist. Another possible situation deals with a population with mostly narrow-filters. In the latter population, wide-filter males can feasibly avoid mate choice rejection by learning from older, narrow-filter males. Therefore, the average reproductive success of wide-filter birds is enhanced by the possibility of learning, and vocal learning and large song repertoires (i.e. wide filters) go hand-in-hand.

The cultural trap hypothesis is one example of gene-culture coevolution, in which selective pressures emerge from the interaction between genotypes and their cultural consequences.

Possible correlation with cognitive ability
Various studies have shown that adult birds that underwent stress during critical developmental periods produce less complex songs and have smaller HVC brain regions. These has led some researchers to hypothesize that sexual selection for more complex songs indirectly selects for stronger cognitive ability in males. Further investigation showed that male song sparrows with larger vocal repertoires required less time to solve detour-reaching cognitive tasks. Some have proposed that bird song (among other sexually selected traits such as flashy coloring, body symmetry, and elaborate courtship) allow female songbirds to quickly assess the cognitive skills and development of multiple males.

Examples of culturally transmitted behaviors in birds
The complexity of several avian behaviors can be explained by the accumulation of cultural traits over many generations.

Bird song
In an experiment regarding at vocal behavior in birds, researchers Marler & Tamura found evidence of song dialects in a sparrow species known as Zonotrichia leucophrys. Located in the eastern and southern parts of North America, these white-crowned song-birds exhibit learned vocal behavior. Marler & Tamura found that while song variation existed between individual birds, each population of birds had a distinct song pattern that varied in accordance to geographical location. For this reason, Marler and Tamura called the patterns of each region a "dialect": however, this term has since been disputed, as different types of in bird song are much less distinct than dialects in human language.

By raising male sparrows in various acoustic settings and observing effects on their verbal behavior, Marler and Tamura found that sparrows learned songs during the first 100 days of their lives. In this experimental setting, male birds in acoustic chambers were exposed to recorded sounds played through a loudspeaker. They also showed that white-crowned sparrows only learn songs recorded from other members of their species. Marler and Tamura noted that this case of cultural transmission was interesting because it required no social bond between the learner and the emitter of sound (since all sounds originated from a loudspeaker in their experiments). However, the presence of social bonds strongly facilitates song imitation in certain songbirds. Zebra finches rarely imitate songs played from a loudspeaker, but they regularly imitate songs of an adult bird after only a few hours of interaction. Interestingly, imitation in zebra finches is inhibited when the number of siblings (pupils) increases.

Innovative foraging
In 20th century Britain, bottled milk was delivered to households in the early morning by milkmen and left on doorsteps to be collected. Birds such as tits (Paridae) began to attack the bottles, opening the foil or cardboard lids and drinking the cream of the top. It was later shown that this innovative behavior arose independently in several different sites and spread horizontally (i.e. between living members) in the existing population. Later experimental evidence showed that conformity may lead to the horizontal spread of innovative behaviors in wild birds, and that this may in turn result in a lasting cultural tradition.

A spread of new foraging behaviors also occurred in an Argentinian population of kelp gulls (Larus dominicanus). During the 20th century, individuals in this population began to non-fatally wound the backs of swimming whales with their beaks, feeding on the blubber and creating deeper lesions in areas that were already wounded. Aerial photographs showed that gull-induced lesions on local whales increased in frequency from 2% to 99% from 1974 to 2011, and that this behavior was not observed in any other kelp gull populations other than two isolated incidents. This implies the emergence and persistence of a local tradition in this population of gulls.

Migration
Juvenile birds that migrate in flocks may learn to navigate accurately through cultural transmission of route choice skills from older birds. Cultural inheritance of migration patterns has been shown in bustards (Otis tarda), and the pattern of inheritance was shown to depend on social structures in the flock.

Avian social networks
Social networks are a specific mechanism of cultural transmission in birds. Information learned in social contexts can allow them to make decisions that lead to increased fitness. A great deal of research has focused on the communication of new foraging locations or behaviors through social networks. These networks are currently being analyzed through computational methods such as network-based diffusion analysis (NBDA).

In wild songbirds, social networks are a mechanism for information transmission both within and between species. Interspecific networks (i.e. networks including birds of different species) were shown to exist in multispecies flocks containing three different types of tits whose niches overlapped. In this study, knowledge about new feeding areas spread through social interactions: more birds visited the new area than the number of birds that discovered the area independently. The researchers noted that information likely travelled faster among members of the same species (conspecifics), but that individuals did not depend solely on conspecifics for transmission. Another study on army-ant-following birds has also evidenced interspecific transmission of foraging information.

A recent study used RFID identification transponders to experimentally manipulate avian social networks: this scanner technology allowed them to restrict access to feeders for some birds and not others. Their data showed that individuals are more likely to learn from those who were able to enter the same feeding area as them. Additionally, the existing "paths" of information transmission were altered following segregation during feeding: this was attributed to changes in the population's social network.

Others have been able to predict the pattern information transmission among individuals based on a preexisting social network. In this study, social interactions of ravens (Corvus corax) were first analyzed to create a comprehensive network. Then, the order in which individuals learned task-solving behavior from a trained tutor was compared with the network. They not only found that the pattern of learning reflected the network that they had built, but that different types of social connections (such as "affiliative interactions" and "aggressive interactions") characterized different rates of information transmission and observation.

Conformity in avian culture
Bartlett and Slater observed call convergence (i.e. conformity) in budgerigars introduced into groups with different flock-specific calls than their own. They also found that the original calls of flock members did not change significantly during this process.

Conformity is one mechanism through which innovative behaviors can become embedded in culture. In an experimental setting, tits preferentially adopted the locally popular method of opening a two-action puzzle box even after discovering the other possible way of accessing the food. This formed diverging local traditions when different populations were seeded with birds specifically trained in one method.

Other research showed that although conformity has a strong influence on behaviors adopted by birds, the local tradition can be abandoned in favor of an analogous behavior which gives higher reward. This showed that while conformity is a beneficial mechanism for quickly establishing traditions, but that unhelpful traditions will not necessarily be adhered to in the presence of a better alternative.

In some cases, conformity-based aggression may benefit individuals who conform to traditions. Researchers used the framework of sexual selection and conformism in of song types of songbirds to model territorial aggression against individuals with non-conforming song types. Their model showed that aggressors won more frequently when targeting non-conformers (than in un-targeted or random aggression). They also found that alleles for conformity-enforcement propagated more effectively than alleles for tolerance of non-conformity.

Finally, other species of birds have been observed to conform to the personality of other individuals in their presence. Gouldian finches (Erythrura gouldiae) exist in red- and black-headed subtypes, and these subtypes have been shown to have different levels of boldness (measured by the time taken to explore new areas, and other similar tests). Experiments placing black-headed birds (known to be less bold) in the company of red-headed birds (known to be more bold) resulted in the black-headed bird performing "bolder" behaviors, and red-headed birds became "shyer" in the presence of black-headed ones. The experimenters hypothesized that this individual-level conformity could lead to stronger social cohesion.