28-passage one
Social learning in animals is said to occur when direct or indirect social interaction facilitates the acquisition of a novel behavior.
It usually takes the form of an experienced animal (the demonstrator) performing a behavior such that the naïve animal (the observer)
subsequently expresses the same behavior sooner, or more completely, than it would have otherwise.
One example of social learning is the acquisition of preferences for novel foods.
Some experiments have suggested that among mammals, social learning facilitates
the identification of beneficial food items, but that among birds, social learning helps animals avoid toxic substances.
For example, one study showed that when red-wing blackbirds observed others consuming a colored food (30)
or a food in a distinctly marked container and then becoming ill, they subsequently avoided food associated
with that color (35) or container. Another experiment showed that house sparrows consumed less red food
after they observed others eating (40) red food that was treated so as to be noxious.
Studies on non-avian species have not produced similar results, leading researchers
to speculate that avian social learning may be fundamentally different from that of mammals.
But Sherwin's recent (50) experiments with domestic hens do not support the notion that
avian social learning necessarily facilitates aversion to novel (55) foods
that are noxious or toxic. Even when demonstrator hens reacted with
obvious disgust to a specific food, via vigorous head (60) shaking and
bill wiping, there was no evidence that observers subsequently avoided
eating that food. Sherwin's research team speculated that ecological
or social constraints during the evolution of this species might have
resulted in there being little benefit from the social learning of atability,
for instance, selective pressures for this mode of learning would
be reduced if the birds rarely encountered noxious or toxic food
or rarely interacted after eating such food, or if the consequences
of ingestion were minimal. (80) In a related experiment the same
researchers showed that if observer hens watched demonstrator
hens react favorably to food of a particular color, then observer
hens ate more food of that color than they ate of food of other colors.
These results confirmed that avian species can develop preferences
for palatable food through social learning.
