The evidence for the existence of discrete basic emotions is vast. A brief summary of the main supportive findings include: common cross-cultural facial expressions and eliciting events, and presence of these emotions in other primates (Ekman & Friesen, 1975) and in infants (Izard, Huerber, Risser, McGinnes, Dougherty;
1980); individual autonomic nervous system response patterns (Stephens, Christie, &
Friedman, 2010), cardiorespiratory activity (Rainville, Bechara, Naqvi, & Damasio, 2006); different but partly overlapping neural structures (Hamann, 2012; Murphy, Nimmo-Smith, & Lawrence, 2003; Tettamanti, Rognoni, Cafiero, Costa, Galati, &
Perani, 2012; Vytal & Hamann, 2010); specific changes in cognition, judgment, and behaviour (Lench, Flores, & Bench, 2011, but see for a dissenting view Lindquist, Siegel, Quigley & Barrett, 2013).
Originally, these various sources of evidence proposed different combinations of basic emotions. However, recent powerful and comprehensive meta-analysis (Murphy et al., 2003; Tettamanti et al., 2012; Vytal & Hamman, 2010) of the neuroscientific evidence seems to consolidate agreement in favour of four (i.e., anger, fear, sadness, and happiness), or possibly five (i.e., the above and disgust) primary classes of affect,
8 which have also, historically, been most consistently reported in the literature (Damasio et al., 2000). As the conceptual representation of emotion states is relatively broad across cultures, with overlapping but not identical linguistic inventories, other emotions are often seen as combinations of these basic emotions or as socially learned variants of these emotions. For example, grief, guilt and loneliness are all variants of basic sadness, (Bower, 1992).
Despite the increasing evidence supporting the theory of discrete emotions, its fundamental assumptions have continued to be scrutinised and challenged, in the search for alternative formulations of the structure of affect. At least four such assumptions seem to conflict with the most common empirical evidence.
Firstly, the central idea that the affective experience is underpinned by a small number of distinct and supposedly independent emotions neither predicts nor explains the common finding that basic emotions are often co-activated. Thus affective
experience seems to be almost always described by a blend of basic emotions, best predicted by the distinction between positive and negative affect.
Secondly, although basic emotions are supposed to transcend cultural and social divides, there appears to be a lack of one-to-one mapping of emotion terms between languages (often even within families of languages). Moreover, despite a scientifically driven attempt to assign specific emotion labels to each discrete emotion, the common language of most people use an assortment of terms to refer to different instances of supposedly the same discrete emotion.
Thirdly, there continues to be a notorious failure to identify a unique pattern of activation of the autonomous nervous system. Subjective experiences of discrete emotions are not readily associated with unique visceral manifestations.
Fourthly, if universal, but also specific emotion classes have evolved as distinct evolutionary adaptations, then the range (in number) and scope (in definition and function) should be equally unambiguous and definitive. Unfortunately, the exact number of discrete emotions has continued to be an infamous shortcoming of the theory of discrete emotions, whose only resolution has been the circumstantial and changing
9 consensus between scientists. Equally, the definition of each discrete emotion, and their exact adaptive function seem to vary with the circumstances in which they are elicited.
Opposing views to the categorical theory of discrete emotions have built around the argument that affective experiences correlate strongly with a small number of orthogonal dimensions. Valence and arousal have been most frequently and reliably reported (Mayer & Gaschke, 1988; Meyer & Shack, 1989; Russell & Feldman Barrett, 1999; Watson, Wiese, Vaidya, & Tellegen, 1999), with various other dimensions also proposed, such as dominance (Mehrabian, 1996; Russell, 1977), anticipated effort, attentional activity, and situational control (Smith, & Ellsworth, 1985). Most recently, Lövheim (2012), proposed a novel account of the organisation of affect, suggesting that the combinations of the levels of three monoamine neurotransmitters (i.e., dopamine, noradrenaline, serotonin) involved in the affective experience, might explain the experience of a distinct set of eight discrete emotions.
The arguments in favour of dimensional emotion theories have received support from physiological correlates of emotional stimuli, such as heart rate and skin
conductance levels, though the breadth and depth of evidence appears more modest than that supporting the categorical accounts. Wundt (1904) developed the first dimensional model, which was later supported by Scherer’s (2002) research showing that people tend to perceive the meaning of stimuli as either positive or negative (the valence dimension) and tend to respond to them either passively or actively (the activation dimension). Others proposed the use of independent bipolar dimensions of pleasure–
displeasure, arousal, and dominance–submissiveness (Russell; 1994), dominance (Mehrabian, 1996; Russell, 1977), anticipated effort, attentional activity, and situational control (Smith, & Ellsworth, 1985), rather than a small number of discrete emotion categories. In general, valence and arousal have been most frequently and reliably reported dimensions (Mayer & Gaschke, 1988; Russell & Barrett, 1999). In a
dimensional taxonomy, all emotion categories vary quantitatively (Russell & Steiger, 1982) and are mapped within a bipolar dimensional space. However, the dimensional approaches (and their mostly correlational empirical support) have received heavy criticism from every new piece of evidence in favour of basic emotions – especially since, at least conceptually, the two accounts seem mutually incompatible. For example,
10 one of the most important dimensions (arousal) appears to be confounded with the intensity of emotions (Reisenzein, 1994; Wintre & Vallance, 1994).
1.1.2 Core affect and the psychological construction of emotional experiences The view of emotions as various manifestations of core affect evolved from the family of dimensional theories of emotions (i.e., the circumplex model; Russell, 1980, 2005) and comes to answer the fundamental issues raised above. At a structural level, the core affect is defined by two dimensions (or axes): pleasure-displeasure, and activation-deactivation (Yik, Russell, & Steiger, 2008). Both these dimensions are supposed to be expressed simultaneously, in a singular experience, which bridges the previous concepts of emotion and mood - thus at times being a continuous experience, not necessarily directed at an eliciting agent (much like mood), but at other times, can become very intense and overtly linked to an eliciting stimulus (much like pain, or the classical concept of emotions).
The core affect is defined as having two fundamental characteristics. Firstly, it is unique to each individual, and greatly variable from situation to situation (Kuppens et al., 2007). Secondly, it changes in response to many internal and external influences, but most notably only in relation to cognitively processed information (Russell, 2009).
When information is not consciously attended, its influence on core affect is said to diminish. Of course, this account fails to acknowledge the experience of emotions in the absence of conscious processing of the stimuli, such as either through masked
presentation beyond the perception threshold (Morris, Öhman, & Dolan, 1998; Pessoa, 2005; Whalen, et al., 1998), in clinical cases of amnesia (Feinstein, Duff, & Tranel, 2010; Hamann, Cahill, McGaugh, & Squire, 1997), or the more common everyday occurrence of the "petit madeleine" effect (Proust, 1982/1921). The concept of core affect is not equivalent to the full spectrum of emotional experiences, but it is an intermediary concept between emotion and mood, whose manifestation is highly individual and situation specific.
The role of core affect in the emotional experience is through a series of processes known as psychological construction (Russell, 2009), which define (1) the
11 behavioural and experiential components of the emotional episode (e.g., facial
movement, vocal tone, peripheral nervous change, attribution of causation, conscious subjective experience, etc.), (2) the associations between the different components, and (3) the categorisation of the pattern of components as a specific emotion. Thus,
psychological construction is responsible for the subjective experience (i.e., individual token events), which may or may not be perceived and classed as discrete (or not so discrete) emotional experiences. The process of psychological construction is not meant to provide a deterministic account of the emotional experience, by acknowledging that this is individual to each person, and specific for each situation. It rather contrasts the biological construction assumed by the theory of discrete emotions, and provides a framework which accommodates the notorious variation of emotional experiences between different cultures, people, and situations.
The psychological constructivist model provides a novel explanation for the origin and role of discrete emotion classes. In managing everyday situations, people often have to be able to describe and identify the emotions they are feeling, and also be able to communicate this to other people. Thus, emotion words (such as fear, anger, sadness) are seen as answering a social need to communicate, rather than an empirical need to classify uniform processes. In everyday situations, the components of
psychological construction (detailed above) are occurring in various forms. And while each emotional experience is different, some similarities will emerge, as a matter of degree (some situations more similar than others). In an attempt to organise, compare, understand and communicate, people assign certain experiences to certain classes, without all situations being equal. For example, one situation might feel like a perfect example of what the experience of fear would be, while other situations might be only mediocre or borderline examples. However, although the subjective experience of emotion is organised, understood, and communicated using the familiar mental categories of anger, fear, sadness, shame, etc. the processes by which they were experienced are fundamentally unique. They are only reported as fear, or anger, or happiness, because people need to refer to their emotional experiences (either for own reflection or for communication) using a system which is efficient, useable and which is also recognised by other people.