Lecture 2: Threat-related experience

And therefore, we need to dig further: is there any reason for the co-existing emotional experiences? For example, we usually use the terms fear and anxiety interchangeably, as if they were the same thing. They are both negative by valence, with strong physiological arousal. But from the perspective of cognitive psychology, they are different. We consider fear as A present-oriented state designed to protect the individual from a perceived immediate threat, and anxiety refers to a future-oriented state responding to an anticipated threat.

So they are similar because we are engaged in the same information: a threat, which is common to both fear and anxiety. However, fear and anxiety differ in how the threat-related information is processed. If it is close to us and we are pretty much sure about it, it will be fearful. If it is distant from us and it is very vague, uncertain to us, it will be more anxious. So during dental practice, what we need to do is not just to identify if patients show fear or anxiety – that’s only the first step. The critical part is to find out the threat underneath their experience.

For example, it could be the disease or even us, the dentists, to be considered a threat by patients!

Back to our definition of emotion, we may consider fear and anxiety as the emotional feelings related to a threat. And during dental practice, pain is usually the threat that makes people scared. Now we need to consider the behavioural part – fear, and pain, and potentiate avoidance, the behaviour that patients will not come to see you, the dentist. If avoidance and fear just link to pain, all we need to do is to relieve their pain. The problem is that the fear of pain, not pain per se, may elicit great avoidance.

For example, patients may avoid treatment if they keep on asking themselves, ‘what if the treatment becomes very painful?’ The link between fear and avoidance, or fear-avoidance, is very detrimental because patients would cut down their relationship with dentists. And eventually, their oral health would get worse.

We just say fear and anxiety are different concepts related to the threat. That does not mean they are independent of each other. Fear and anxiety usually co-exist during dental practice. And we can describe the dynamic relationship between them from the famous defense fear system model. According to the model, the brain participates in processing threatening information differently, according to the distance between an individual and the threat. For example, when a threat is still distant from us, we may not have a clear idea of what it is and need to collect more information for making a decision. That is when the prefrontal cortex and other brain regions need to integrate more information.

In contrast, when the threat is approaching, we need a quick physiological response to escape from it. At the moment, the brain regions associated with quick response, such as the hypothalamus and the brainstem, will play a more important role.

Now we can look into more issues regarding fear and anxiety. I want to show you two experiments, which are good examples of how to test a psychological model. According to the defense fear system, a threat may elicit a dynamic emotional experience when it is an approach to an individual. For example, patients may feel anxious when the dentist is about to pick up a needle, and they may have a stronger fear when the needle is put in their mouth. In one study published in Science, researchers utilized a computer game, more or this like this one, to mimic the dynamic encounter of a threat.

As you can see here, the subject needs to control the black dot, which cannot be touched by the attacker. The attacker will try to approach the dot. The subject received a brain scan when playing this game. They found a stronger activation in the prefrontal cortex when the attacker is still distant away and more activation in the brainstem when the attacker is approaching. In another study, they even designed a robotic spider as a threat. The spider will move toward or away from the subjects. Again, the pattern of brain activation and feelings shift as the spider moves. The findings support the defense fear system model and demonstrate the dynamic relationship between fear and anxiety.

Now I hope that I can convince you that our emotional experiences, which seem to be distinct from one to another, are actually interrelated. Again, from the perspective of cognitive neuroscience, what matters is information processing – for example, both fear and anxiety relate to the processing of information of threat. This is very important for the clinical care of anxious patients. I have seen some dentists try to persuade patients that ultrasound scaling is okay because it is not very painful. In fact, patients feel nervous about dental scaling because the pain or sensitivity during scaling occurs unpredictably. It is the unpredictability of pain, rather than the pain itself, that leads to their anxiety.

In other words, our emotion is associated with how the brain processes the information of a stimulus, rather than the stimulus per se.