Afecto positivo y negativo: ¿Una dimensión bipolar o dos dimensiones unipolares independientes? / Positive and negative affect: One bipolar dimension or two independent unipolar dimensions?

RESUMEN

Desde los trabajos pioneros de Bradburn (1969) el afecto positivo y el afecto negativo han sido concebidos como dos dimensiones unipolares independientes, aunque todavía se mantiene hoy en día la controversia teórica entre defensores de un modelo unidimensional bipolar y los de un modelo bidimensional unipolar. El objetivo de este artículo es revisar la problemática que rodea esta controversia tomando en consideración por un lado, los dos estados afectivos (el humor o tono afectivo y las emociones) y por otro lado, revisando los estudios y modelos teóricos provenientes de distintas áreas tales como Psicometría, Psicología Básica, neurociencia, Psicología Clínica y Psicología de la Salud. Finalmente, se ofrece una posible explicación a los datos contradictorios obtenidos en los distintos estudios. Se sugiere la conveniencia de hacer estudios claramente diferenciados sobre el humor y las emociones. Sobre el humor existen pocos trabajos, pero éstos ofrecen mayor apoyo a un modelo unidimensional bipolar. Sin embargo, sobre las emociones hay mayor cantidad de estudios que ofrecen mayor apoyo a un modelo bidimensional unipolar.

ABSTRACT

Since the seminal contribution of Bradburn (1969), positive and negative affect have been conceived as two independent unipolar dimensions. However, the controversy between these ideas and the supporters of a single bipolar dimension is nowadays still alive. In this review we identify two problems. The first one is of a conceptual nature, because, as Russell and Carroll (1999) pointed out, the term affection is not unambiguously defined and rarely researchers in this field make an explicit definition. According to Rosenberg (1988), there are at least two types of affective states, which are widely acknowledged emotions and mood, or affective tone. Emotions are characterized for, and differ from mood in, appearing in response to an event, being intense, short-lived and specific. They are also characterized by provoking important physiological reactions in the individuals, as well as recognizable patterns of facial expression, and by determining individuals to behave congruently in relation to the emotion they are experiencing. Combining these two very different components of affect hinders the comparison of the work of different authors, and also the development of theoretical models combining the different aspects included within this concept. The second problem is related to the measurements used in the research assessing affect, where the possible existence of events or circumstances causing the affective state is not normally considered. Likewise, measurement regarding the duration of the affect are rarely performed, and objective measurements such as physiological correlates or facial expressions are not frequently collected. Consequently, instruments do not normally distinguish between mood and emotion. The aim of this paper is to review the most relevant questions regarding this debate taking into account, on the one hand, the two affective states included in the concept of affectivity (i.e., mood and emotion) and, on the other hand, the empirical and theoretical contributions provided by a wide range of disciplines such as Psychometry, Basic Psychology, neuroscience, and Clinical and Health Psychology. From Basic Psychology and Psychometry we reviewed the three fundamental argumentations advocating for an independence of positive and negative affect, as identified by Diener and Emmons (1984) and Russell and Carroll (1999) (1) that the correlation between items that evaluate the positive affect and negative affect is low, (2) that the correlation of items within the categories of positive affect and negative affect is high, and (3) that the two dimensions of affect correlate differently with other variables. A fourth argument is discussed referring to the variations of both affect types observed throughout a lifetime (Bushman & Crowley, 2010; Windsor & Anstey, 2010). From the neuro-scientific perspective we reviewed studies providing data on brain structures and neurotransmitters involved in both affect types, noting that all these studies have been carried out by inducing intense moods, which indeed might be classified as emotions rather than humor. From Psychopathology and Clinical Psychology we reviewed those disorders in which states of positive and negative mood can be experienced in a very intensive manner (positive and negative emotions), in very short periods of time and even at the same time. We also reviewed research studying the independent presence of positive and negative affect in several disorders, as well as some theoretical models on depression that indicate the possibility and desirability of adopting a 'dual' perspective in the assessment and the intervention strategies of both types of emotions in the depressive disorder and other disorders. A proposal about the reason of such contradictory findings is presented, and we suggest that research about this topic should be better conducted setting apart mood from emotions using tools that allow measuring those elements capable of distinguishing between affect types. Although the few existing studies about affective traits and mood seem to support the bipolar one-dimensional model, the conclusions drawn from the numerous investigations about emotions favor the two independent unipolar dimensions model.