What is emotion?
Fehr and Russell (1984) observed succinctly: “Everyone seems to understand what an emotion is until they are asked to define it. At that point, no one seems to know” (p. 464). In one of the most influential works on emotion, James (1884) addressed the question of what emotion is, emphasising that a plethora of definitions had been proposed before he introduced his own theory. However, the diversity of approaches to understanding emotion didn’t end with James’ seminal work; since the beginning of the 20th century, emotion has been conceptualised in a myriad of ways. These interpretations of emotion vary according to a variety of factors, including historical and cultural contexts, as well as the different theoretical frameworks in which they are embedded.
To address the challenge of defining emotion explicitly, Kleinginna and Kleinginna (1981) analysed nearly one hundred definitions of emotion. Their analysis revealed that these definitions emphasised different facets of emotion, which could be grouped into eleven categories. For example, some definitions emphasised the physiological aspects of emotion, while others emphasised expressive behaviour. Some perspectives treated emotion as a disruptive factor (e.g., related to psychopathology), while others focused on the functions of emotion (e.g., related to evolutionary advantage). The task of defining emotion and distinguishing it from other affective phenomena (such as mood, preference, attitude, passion, affect) is not easy.
Theoretical approaches to emotion and its measurement
Is emotion a bodily reaction? Is emotion a feeling?
The debate between James-Lange and Cannon-Bard theories underscores two distinct approaches to understanding emotion. According to the James-Lange theory, developed independently by William James and Carl Lange, emotions arise as a response to physiological changes that occur after we perceive an emotion-inducing event. In this view, bodily reactions are primary, preceding the actual emotional experience. James argued that without the bodily reactions associated with an emotion, the emotion itself would cease to exist.
Contrarily, the Cannon-Bard theory posits that the perception of an emotion-inducing event and the physiological response to it happen simultaneously, originating from the central nervous system, particularly the thalamus. Walter Cannon and Philip Bard disputed the James-Lange theory, arguing that the physiological responses associated with different emotions lack specificity and can be similar in non-emotional states. They also noted that removal of bodily reactions did not eliminate emotions and artificially inducing such reactions did not evoke the associated emotions.
These differing theories sparked a significant controversy known as the “sequence problem”, focusing on the order of physiological and emotional responses to an emotion-inducing event. While the James-Lange theory has been influential due to its originality and testability, it was challenged by Cannon and Bard’s centralist approach, which proposed that emotions are first and foremost a brain-based phenomenon
Measuring bodily reactions and bodily feeling
All contemporary major theories of emotion regard bodily reactions as a crucial element of emotion. For instance, according to appraisal theories, physiological responses facilitate emotion expression and initiate action tendencies. Therefore, their measurement is of significance. When investigating emotions, a wide array of psychophysiological indicators can be utilized and combined. They all mitigate self-report biases. The selection of these indicators should be driven by the specific research question, not simply by the aim to “measure a given emotion.”
These measures often pertain to cardiovascular responses (such as heart rate, heart rate variability, systolic and diastolic blood pressure, pre-ejection period, total peripheral resistance), electrodermal activity (like skin conductance level, skin conductance responses), respiratory activity, postauricular reflex, or startle reflex measurement. Indicators such as heart rate and startle reflex amplitude tend to reflect emotional valence, while skin conductance and pupil diameter are more related to arousal. Some primarily indicate sympathetic activity (like skin conductance level), a combination of sympathetic and parasympathetic activity (like heart rate), or predominantly parasympathetic activity (like heart rate variability).
The physiological changes triggered by emotion form an integrated pattern of responses, making it crucial to carefully choose and analyze the relevant psychophysiological indicators for a specific study. Several guidelines for different measures can be found on the Society for Psychophysiological Research website.
Different ways of measuring emotions cross-culturally
Depending on how one defines affect and cognition, affective sciences can either be seen as integrated with or complementary to cognitive sciences. Emotion, though a concept often applied in everyday life, can also be defined and studied scientifically. Several theories have conceptualized emotion, and great strides have been made in studying emotion and its effects in terms of concepts, methods, and measures over the past century.
Contemporary approaches to emotion each have their own specific definitions and core tenets concerning emotion. They notably differ on the emotional component they focus on, such as expression, action tendency, bodily reaction, feeling, or appraisal. However, they partially overlap, and there’s increasing conceptual clarity around emotion, often seen as a rapid process focused on a relevant event. During an emotional episode, elicitation mechanisms shape an emotional response composed of changes in several components.
Emotion is a complex and highly interactive phenomenon, hence there’s also increasing agreement around emotion measurement. All measures (e.g., self-reported or physiological) are relevant for understanding emotion, and their selection largely depends on which aspect(s) of emotion one wishes to study. Much is at stake when using a measure to properly capture what one intends to measure, making the issue of emotion measurement one that needs careful consideration. Moreover, it’s important to keep in mind that measuring emotions can impact the emotional response itself.
Timing is a crucial factor when trying to measure emotions, especially in applied settings. The advent of virtual reality, which allows participants to be immersed in realistic situations, can facilitate the elicitation of emotions that are closer to real-life situations. This immersive technology offers a controlled, yet realistic context to study natural emotional expressions and emotional recognition.
However, trying to measure all components of an emotion simultaneously presents its own set of challenges due to the complexity of emotions. For instance, measuring the duration of an emotion is a complex task because it’s hard to distinguish whether it’s the duration of a new emotional episode (triggered by the memory of the event) or the duration of its first occurrence that’s being measured.
Over the past three decades, the rise of affective sciences has led to significant conceptual and methodological advancements in the understanding of emotions, as well as an influx of empirical findings. However, a critical question for current models of emotion is whether specific emotional domains can be adequately covered within the scope of existing general models of emotion or whether domain-specific models are necessary.
Models pertaining to the mechanisms of approach motivation, reward, and pain have typically been studied independently of emotion models. However, the field of emotion research would benefit greatly from formally considering the relationships of these constructs with key emotion sub-processes, components, or dimensions. The text concludes with a confident assertion that the coherent approaches offered by the affective sciences provide perspectives for a better conceptualization, understanding, and measurement of affective processes, particularly emotions.
References
Coppin, G. and Sander, D., 2021. Theoretical approaches to emotion and its measurement.