Perceiving faces and social cues
Even babies find other people fascinating [All Ages]
How do we come to be interested in other people?
Play the audience the following clip explaining that from birth human infants show a preference to follow things that look like faces (the paddle with two circles at the top and one at the bottom) more than anything else.
Although the senses are relatively immature at birth, they are still good enough to detect social stimuli. Babies pay special attention to humans and can recognise the human face even with very poor vision. Faces are like magnets to a baby, capturing their attention so that they can hardly look away.
Q: What does this tell us about how important other people are to us?
A: The fact that even newborns pay so much attention to faces over all the other new things they see suggests that we are born with some social perception already programmed into our brains. More than any other animal, humans have a very long period of time when they are completely dependent on other people to stay alive. While a baby chicken or cow is up and running almost as soon as they are born, babies are very vulnerable for a very long time.
It has been shown that the longer an animal spends in childhood, the more creative and intelligent it is. Another thing that animals that have long childhoods have in common is that they tend to be social species. One theory is that we have evolved to be so intelligent because we are social animals. On the other hand, it might be because we are so intelligent that we became social or that the two capacities evolved side-by-side.
How do we pay attention to people around us? [All Ages]
Do older children and adults pay as much attention to faces as babies?
In the following video Esme is wearing a machine that enables us to see exactly where her eyes are moving. When she sees a scene with no faces her eyes travel all over the place. When she sees a scene with a face in it she tends to look at the face the most. And when she sees a face quite close up she tends to look most at the eyes and mouth. This is very typical of the way that most people direct their attention. Even as teenagers and adults, faces are still very interesting and attention-grabbing for us.
Q: Why do we focus on people’s eyes and mouth?
A: When we are looking at a face, we tend to focus on the areas (the eyes and mouth) that will 1) signal the focus of that person’s attention, 2) enable us to establish a social bond with that person and 3) to work out how that person is feeling.
Social cuing: What are you looking at? [All Ages]
When we look at faces, do we pay attention to where they are looking?
Stop in mid-speech and stare at something in a far corner of the room, behind or above the audience. Most people should turn to stare in the same direction.
Explain that from early on, we are very sensitive to gaze & automatically follow another person’s direction of gaze which could signal a potential threat.
Q: Why do we automatically follow other people’s gaze?
A: We probably follow other people’s gaze because it was important when we evolved to be aware of whether there were any threats nearby which might be what the person was looking at.
Q: When do we start to follow other people’s gaze?
A: We start to follow other people’s gaze at around 9-months of age. Even before infants can speak they will follow their mother’s gaze when she is looking somewhere else and will point to things that they want to direct their mother’s attention to them.
The Hollow Mask Illusion: Looking at inside-out faces [All Ages]
Does the brain have expectations about how faces ought to look?
Play the audience the following video of the hollow mask illusion.
Explain that as the mask rotates, the face seems to ‘pop-out’ again from the back of the mask. Only when it reaches a certain angle where most of the features are concealed can we see that it is actually hollow. It seems that the parts of the brain for processing faces only expect faces to be pointing outwards (not inside out) and so our eyes just see the inside of the mask as a face pointing out.
Q: Why does the brain have an expectation that faces should point out.
A: The brain probably has an expectation of faces pointing out because in day-to-day life it only ever sees pointing-out faces. This might be true of lots of things that the brain doesn’t have as strong expectations about but perhaps because faces are so important to us, these expectations and mental models are especially noticable. This is called “top-down” knowledge. It is top-down because it is the expectation from our brain is influencing what our eyes see.
The Thatcher Illusion: Looking at upside-down faces [All Ages]
Do we recognise faces upside down?
Show the audience the first picture and ask them to shout out who they think it is.
Then show them the rotation of the face.
Explain that as we get older and have more experience of faces we begin to build mental models and expectations about how faces ought to look. This means that we can do alot of processing all at once without having to concentrate on paying attention to all the individual features. This means that when we see an upside-down face the brain registers that all the features are in the right place relative to each-other but does not pay much attention to the details of the face.
Q: If these sorts of mental models are dependent on experience of faces, does that mean that babies and young children wouldn’t succumb to the illusion?
A: If you were younger than about 8-years of age, you would be less susceptible to the upside down face effect and would have immediately known why the faces were different but by the time you are an adolescent you have become somewhat of a face expert so are far more susceptible to the illusion.