The physiological changes associated with emotion are very familiar to us. It is hard to imagine even the mildest emotional experience without its attendant arousal. [arousal the fluctuating state of physiological activation of the nervous system]. When we are happy or sad, afraid or angry, jealous or disgusted, the changes in our bodies are obvious. We might experience ‘butterflies in the stomach’, ‘a sinking feeling’, or ‘our heart in our mouth’. We feel ourselves blush, feel our heart race as we narrowly miss an accident, and feel the drooping depletion in our body that accompanies sadness or depression. We are more aware of the peripheral nervous system than we are of the central nervous system (CNS). We can feel our skin sweating or our muscles tensing, whereas most of us cannot feel our hypothalamus sending out signals, even though we might become aware of the result. We cannot feel our brain doing its work, emotional or otherwise. How do we learn to recognize the bodily changes that accompany our emotional states? Do they differ, depending on the emotion we are experiencing? Can there be emotion without physiological change? Variation in patterns of arousal Emotion is about coping with sudden changes in our environment, changes that have significance for our survival ( physical or social). So the autonomic nervous system (ANS) prepares the body for action and helps it back to quiescence later. These are what we refer to when we talk about changes in arousal. Over the years, psychologists have proposed that the various emotions experienced in everyday life have their own specific response patterns, [response patterns particular patterns of physiological responses, in this case linked to various emotions] in terms of arousal. So, fear should have a different pattern from anger, which in its turn should be different from sadness and happiness, and so on.
These suppositions were endorsed by the much-quoted study of Wolf and Wolff (1947). These researchers investigated a man who had had a gastric fistula inserted (a pipe directly into the stomach) for medical reasons. Wolf and Wolff (1947) found clear and consistent gastric differences between anxiety and anger. But further evidence demonstrating differential physiological response patterns for different emotions was scarce for many years. Lacey and Lacey (1970) found some evidence for emotion specificity in the cardio-vascular system, but it was not until 1990 that Levenson, Ekman and Friesen offered clear support for emotional response patterning. By instructing people on which facial muscles to use, they asked them to hold various emotional expressions for ten seconds. They found that happiness, surprise and disgust (or, at least, the facial expressions associated with these emotions) are characterized by a different heart rate than anger, fear and sadness, for example. Moreover, skin temperature is found to be lower in fear than in anger.