Burkart et al. assess what studies on general intelligence in nonhuman animals mean for current theories about the evolution of general intelligence. Although we agree with their conclusions in favor of the cultural intelligence approach, we do not entirely agree with their assessment that the relationship between general intelligence and socio-cognitive abilities is poorly understood in animals and humans (sect. 4.2, para. 4).

In this commentary, we aim to place their conclusion in the perspective of an already substantial evidence base demonstrating a relationship between general intelligence and socio-cognitive abilities in humans. We review recent meta-analyses on this relationship, focusing on connections among general intelligence, theory of mind (ToM; Baron-Cohen et al. Reference Baron-Cohen, Jolliffe, Mortimore and Robertson1997; Baron-Cohen et al. Reference Baron-Cohen, Wheelwright, Hill, Raste and Plumb2001) and ability-based emotional intelligence (EI; Mayer & Salovey Reference Mayer, Salovey, Salovey and Sluyter1997).

ToM is the ability to attribute mental states (e.g., emotions, intentions, or beliefs) that differ from our own (Baron-Cohen et al. Reference Baron-Cohen, Leslie and Frith1985; Baron-Cohen et al. Reference Baron-Cohen, Wheelwright, Hill, Raste and Plumb2001). ToM is widely assessed using the Reading the Mind in the Eyes Test (RMET; Baron-Cohen et al. Reference Baron-Cohen, Jolliffe, Mortimore and Robertson1997; Reference Baron-Cohen, Wheelwright, Hill, Raste and Plumb2001), which can reveal intersubject differences in social cognition and emotion recognition across different groups and cultures (Fernández-Abascal et al. Reference Fernández-Abascal, Cabello, Fernández-Berrocal and Baron-Cohen2013). A recent meta-analysis involving 3,583 participants revealed a small positive correlation between general intelligence and RMET score (r = .24), with both verbal and performance IQ showing similar correlations with RMET score (Baker et al. Reference Baker, Peterson, Pulos and Kirkland2014). The authors of that meta-analysis concluded that intelligence contributes significantly to ToM, with verbal and performance IQ contributing equally.

EI is a construct central to conceptualizing and evaluating socio-cognitive abilities. EI refers to the ability to reason validly with emotions and with emotion-related information and to use emotions to enhance thought (Mayer & Salovey Reference Mayer, Salovey, Salovey and Sluyter1997; Mayer et al. Reference Mayer, Roberts and Barsade2008). The most common measure of ability-based EI is the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT; Mayer et al. Reference Mayer, Salovey and Caruso2002). This test assesses the four primary abilities (branches) of the Mayer and Salovey model of EI: perceiving emotions in oneself and others, using emotions to facilitate thought, understanding emotional information, and regulating emotions in oneself and others (Mayer & Salovey Reference Mayer, Salovey, Salovey and Sluyter1997). MSCEIT assesses these emotional abilities by asking the subject to solve a series of emotion-based problems, thereby avoiding the high risk of bias associated with self-report EI measures. MSCEIT-based studies have demonstrated a relationship between general intelligence and EI. For instance, Webb et al. (Reference Webb, Schwab, Weber, DelDonno, Kipman, Weiner and Killgore2013) found significant correlations of MSCEIT score with general IQ, verbal IQ, and performance IQ. A meta-analysis of 53 studies involving 3,846 participants found positive correlations of scores on the MSCEIT or its forerunner MEIS with general intelligence (r = .30), verbal intelligence (r = .26), and nonverbal intelligence (r=.23) (Kong Reference Kong2014).

Factor-analytic exploration of how mental abilities correlate with one another suggests an even broader range of intelligences linked to ability-based EI, including fluid intelligence, crystallized intelligence, and quantitative reasoning (Legree et al. Reference Legree, Psotka, Roberts, Robbins, Putka and Mullins2014; MacCann et al. Reference MacCann, Joseph, Newman and Roberts2014). These intelligences lie within the second stratum of the Cattell-Horn-Carroll model (McGrew Reference McGrew2009). Further evidence for the relationship of ability-based EI with a range of broad intelligences comes from a study involving more than 12,000 people ranging in age from 17 to 76 years (Cabello et al. Reference Cabello, Sorrel, Fernández-Pinto, Extremera and Fernández-Berrocal2016). In this study, MSCEIT scores varied with age according to an inverted-U curve: Younger and older adults scored lower than middle-aged adults, just as reported for several other intelligences.

In this way, the extensive literature on ability EI provides substantial evidence linking various types of intelligence to socio-cognitive abilities. Nevertheless, one thing that remains unclear is how the EI assessed on the MSCEIT relates to executive functions, some of which – such as inhibitory control and working memory – strongly correlate with general intelligence, as Burkart et al. point out (sect. 1.1.2, para. 2). Gutiérrez-Cobo et al. (Reference Gutiérrez-Cobo, Cabello and Fernández-Berrocal2016) systematically reviewed 26 studies on the relationship between EI and cognitive processes reflected in tasks such as the Stroop task or Iowa gambling task. The authors found that performance-based ability EI (such as measured on the MSCEIT) – but not self-report EI – positively correlated with efficiency on emotionally laden tasks. In contrast, no correlations were observed between EI measured in various ways and non-emotionally laden tasks. These findings suggest that the greater intelligence reflected in higher ability-based EI can mean superior performance on emotionally laden socio-cognitive tasks, but not necessarily on other kinds of tasks.

In summary, the body of studies examining ToM and ability-based EI build a strong case that general intelligence, particularly intelligence in the second stratum of the Cattell-Horn-Carroll model, is associated with socio-cognitive abilities in humans. Studies of ability-based EI and cognitive processes nuance that this relationship is likely to be complex: For example, higher ability EI may lead to more efficient cognitive processes in emotionally laden tasks but not other tasks. A link between general intelligence and socio-cognitive abilities coincides nicely with studies from affective and social neuroscience showing that emotion processing and cognition in the brain are highly intertwined and mutually determined (Phelps et al. Reference Phelps, Lempert and Sokol-Hessner2014).

Future work should (1) examine to what extent different socio-cognitive abilities are related (e.g., how are ToM and EI related?), (2) analyze to what extent different socio-cognitive abilities relate to general intelligence, (3) test whether and how specific social inputs play a role during ontogenetic construction of socio-cognitive abilities, and (4) identify brain regions involved in different socio-cognitive abilities and examine their relationship and overlap with regions implicated in general intelligence.