|
借用biss mm這裡的高人氣來求助一道閱讀的題目，來自GMAT 28。
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 na?ve 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.
28-3: The primary purpose of the passage is to discuss the
A: techniques used in certain experiments on social learning in birds
B: reasons for the differences between social learning in birds and in mammals
C: question of how social learning manifests itself in birds
D: basis for a widespread belief about a difference in behavior between birds and mammals
E: possible reasons why birds may or may not learn from each other in a particular way
這題我選的是E，但xdjm們的參考答案以支持C者較多。初步先排除A和D，剩下三個選項我的理解是
B: 雖然第一段主要在講哺乳類動物和鳥類行為的差異，但第二段說明鳥類的學習行為也會因為某某因素而不同。這個因素說明為什麼鳥類的學習行為會有差異，但不能因此擴大解釋是這個因素導致哺乳類動物和鳥類行為的差異。
C: manifests itself: to appear or to become easy to see。我對這句話的理解是：本文在討論社會學習的行為如何清楚地呈現在鳥類動物身上。隱含有其他非鳥類動物沒有這種行為、或者這種行為並不明顯。也許是我的想法偏差了，請大家批評。
E: 這是第二段探討的主題，文中確實也給出可能的原因。但這答案顯然也不好，因為有點以偏蓋全了，第一段顯然並不是侷限在這個範圍。
偶對閱讀主題的理解一向不好，請各位xdjm們指點迷津，謝謝!!
[此贴子已经被作者于2005-9-25 13:02:27编辑过] | 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2005-9-25 07:02:00
