Face Perception

 

INTRODUCTION

Have you ever looked at a paint-splattered wall or a grainy wooden plank and suddenly noticed a face-like image staring back at you? If so, you’ve experienced how the visual system is especially sensitive to a special class of objects: faces. Our visual system is so sensitive to facial stimuli that we readily perceive face-like qualities in otherwise random patterns.

Face perception is a mundane task that a socially active human may perform hundreds of times in a day. We acquire indispensable information about others, including mood, age, and level of attentiveness, just by looking at their faces. Research shows that we more readily acquire this information by looking at a person’s face than by hearing him or her speak, analyzing the clothing he or she wears, or observing how he or she walks (Bruce & Young, 1986).

One key aspect of face perception is recognition, or our ability to distinguish different faces from one another. People with a condition known as prosopagnosia experience great difficulty with this task and fail to recognize the faces of others. Those with prosopagnosia can still distinguish what is and is not a face, however. The specific impairment of this disorder suggests that the process of face recognition differs from that of nonfacial object recognition.

Under normal circumstances, we find face recognition remarkably simple, but it is also easy to change the circumstances in such a way that recognition becomes much more difficult. You’ll see this illustrated in the Experience section of this ZAPS lab.

 

Instructions

Click the “Start Trial” button to begin each trial. You will then see three face images on the screen: one on top, and two side-by-side on the bottom. When the images appear, click on the bottom image that you think is a picture of the same person in the top image.

Your responses are being timed, so click an image as quickly and accurately as possible on each trial.

 

Before we begin the actual experiment, let’s try three practice trials.

What should you be doing in each trial?

Click or tap a choice to answer the question.

As quickly as possible, click on the bottom image that shows a different person than the top image.

Taking your time, click on the bottom image that shows the same person pictured in the top image.

As quickly as possible, click the bottom image that shows the same person pictured in the top image.

Taking your time, click the bottom image that shows a different person than the top image.

 

Experience

 

 

 

 

 

Your Data

Data Introdation

Your task in the Experience section was to select the bottom image that you thought was a picture of the same person in the top image as quickly and accurately as possible. As you may have noticed, on some trials the face images were upside down or inverted, whereas in other trials they had a normal orientation.

On the following graph, you will see your reaction time (in milliseconds) plotted along the y-axis, and the type of face image (normal or inverted) plotted along the x-axis.

Based on your experience during the experiment, which set of images was most difficult to match quickly to the top image: the upright faces or the inverted faces? Why?

 

· Graph

 

· Table

 

· Raw Data

 

 

DISCUSSION

 

People tend to have great difficulty recognizing inverted faces, particularly those that are unfamiliar to them. Surprisingly, people perform much better at recognizing inverted nonfacial objects than they do with inverted faces. When a face is inverted, the individual features of that face are also inverted. Studies show that inversion disrupts the relationship between facial features, and this manipulation of features in particular makes a face less recognizable (Hancock, Bruce, & Burton, 2000).

 

In the Experience section, you encountered how inverting face images makes it much more difficult to recognize them. How do we know that changing the relationship between facial features is actually what makes inverted faces harder to recognize?

 

Faces, particularly upright faces, are a special class of objects that our visual system perceives as important information. You learned earlier that the specific symptoms of the condition prosopagnosia suggest that face recognition is a separate process from nonfacial object recognition. Brain imaging studies show that a region of the fusiform gyrus in the right hemisphere may be solely responsible for perceiving faces (Grill-Spector, Knouf, & Kanwisher, 2004; McCarthy, Puce, Gore, & Allison, 1997).

 

Although certain conditions like inversion might make it more difficult to recognize faces, studies show that other circumstances facilitate face recognition. For example, research suggests that people recognize faces more quickly and accurately when viewing members of their own race (Gosselin & Larocque, 2000). In a similar vein, the brain is better at perceiving some expressions better than others. Studies have shown that people more quickly and accurately recognize angry facial expressions than happy expressions, and they recognize men’s angry facial expressions faster than those of women (Becker, Kenrick, Neuberg, Blackwell, & Smith, 2007).

 

From an evolutionary perspective, why might it be more important to quickly recognize angry facial expressions than it is to recognize happy ones?

 

You will initially receive full credit for any answer, but your instructor may review your response later.

Submit Answer

Answer the following questions to complete this ZAPS activity. Your performance in this section accounts for 10% of your grade.

 

Which of the following statements most accurately describes the deficits of someone with prosopagnosia?

Click or tap a choice to answer the question.

“I see faces, but I can never be sure of the identity of a person based on his or her face.”

“I try to describe what I see, but I have great difficulty recognizing objects when looking at them.”

“I have a lot of trouble recognizing when a person is happy versus when a person is sad.”

“I can only recognize the faces of my closest family members.”

Correct!

 

People with prosopagnosia have deficits in their ability to distinguish different faces from one another, regardless of a person’s facial expression or his or her relation to them.

You answered the question correctly on your first attempt, so your grade for the question is 100%.

 

A region of the ________________ in the right hemisphere shows heightened activity levels when a person perceives upright faces.

Click or tap a choice to answer the question.

fusiform gyrus

hippocampus

hypothalamus

prefrontal cortex

Correct!

Findings from a number of studies suggest that a region of the fusiform gyrus is dedicated to perceiving upright faces.

 

We find it rather difficult to recognize inverted faces because inversion changes the relationships among individual facial features.

Click or tap “True” or “False” to answer the question.

Correct!

Face inversion changes the relationship between individual facial features, and we rely on information about the configuration of these features to successfully recognize faces.