There’s nothing quite like the rush of recognition that comes from seeing a familiar face. Scientists have found it very difficult to explain how we identify well-known faces — or how that process differs from the way we perceive unfamiliar ones.
They have long known that the brain contains a network of areas that respond selectively to faces as opposed to other kinds of objects like feet, cars, smartphones. They also knew that humans process familiar and unfamiliar faces very differently. For example, we excel at recognizing pictures of familiar faces even when they are shot in poor light or at odd angles. But we struggle to recognize even slightly altered images of the same face when it is unfamiliar to us: two pictures of a stranger we’ve never seen before, for instance, shown from different perspectives or in dim light.
Now researchers at The Rockefeller University have begun to unravel the mystery of how the brain recognizes familiar faces. They turned to macaques (猕猴), close evolutionary cousins whose face processing networks are better understood and more easily studied than our own.
Using functional magnetic resonance imaging (磁共振成像), Landi and Freiwald measured the animals’ brain activity as they responded to pictures of other monkeys’ faces. Those faces fell into three categories: personally familiar ones belonging to monkeys that the macaques had lived with for years; visually familiar ones whose pictures they had seen hundreds of times; and totally unfamiliar ones. For comparison’s sake, they also showed the monkeys pictures of personally familiar, visually familiar, and unfamiliar objects.
The researchers expected the macaque face processing network to respond in much the same way to the first two types of faces. But instead, the entire system showed more activity in response to the long-time personally familiar faces. Faces that were only visually familiar, meanwhile, caused a reduction of activity in some areas.
“The whole network somehow distinguishes personally familiar faces from visually familiar faces,” says Landi.
Even more surprisingly, the faces of animals whom the macaques had known for years caused the activation of two previously unknown face-selective areas.
One is located in a region of the brain associated with so-called declarative memory, which consists of facts and events that can be consciously recalled. The other area lies in a region associated with social knowledge, such as information about individuals and their position within a social class — “a specific form of memory,” Freiwald says, “that is highly developed in primates (灵长类动物), and certainly in humans.”
【小题1】According to Paragraph 2, which of the following statements is true?| A．The network of areas in the brain can respond equally to faces and to other objects. |
| B．We can hardly identify the picture of people with makeup even if we know them well. |
| C．People are better at recognizing pictures of familiar faces than those of unfamiliar ones. |
| D．Pictures of familiar faces are hard to be recognized if they are taken in the dim light. |
| A．begin to fail or collapse |
| B．investigate something complicated |
| C．undo something to make it separated |
| D．unwind something wrapped around another object |
| A．You store some social knowledge in your declarative memory. |
| B．Your friends’ faces reduce the activity in some parts of the brain. |
| C．A passer-by’s face can activate two face-selective areas in your brain. |
| D．Your brain responds differently to your parents’ faces and to pop stars’ faces. |
| A．What face recognition is |
| B．How the brain recognizes familiar faces |
| C．What methods scientists use in the research |
| D．How people understand face processing network |
