We have all been in situations in which we decided to do something and then had trouble explaining our decision to someone else. A business owner may feel confident about her hiring decision for the job of sales representative, even though all of the candidates had similar credentials and experience. After meeting with the candidates, the owner may have a clear favorite and yet be unable to articulate her rationale to her regional managers. She may tell them instead that she had a “gut feeling” that this person would be the best for the job.

Although we all make some decisions based upon “hunches,” seemingly without conscious reasoning, the process of making such decisions is challenging to study systematically in the laboratory. However, one experimental task known as the Iowa Gambling Task has enabled researchers to explore these hunches from an experimental perspective (Bechara, Damasio, Tranel, 1997). One version of this task involved four decks of cards (A, B, C, and D). Each subject began with $2000 (in pretend money). Subjects were told that they would receive an immediate reward (either $100 or $50) when they selected a card from each deck. However, in an unpredictable manner, some card selections were accompanied by a financial penalty. Although the subjects weren’t informed of the odds of winning or losing money in this task, two decks (A and B) were more likely to yield the higher payoff ($100) but were also more likely to result in a high financial penalty. By contrast, the remaining two decks (C and D) had a lower payoff ($50) but were more likely to result in a lower financial penalty, yielding more money overall over the course of the experiment.

How did healthy subjects respond? During the experiment, a measure known as the skin conductance response (SCR) indicated a heightened emotional response characterized by increased electrodermal activity in the palms of the subjects (e.g., sweaty palms). The researchers reported that after healthy subjects had selected a few of the cards that were associated with the higher financial penalty, they began to exhibit an SCR prior to selecting another card from that deck. Subsequently, they started avoiding the decks with the higher financial penalty (decks A and B). But when asked to describe their response strategy early in the task (after selecting about 20 cards), they typically reported having no clue what was going on—even though their bodies were exhibiting a heightened emotional response to the “risky” decks. After selecting about 50 cards, the subjects conveyed that they had a hunch that certain decks were riskier than others. After selecting about 80 cards, subjects had started to conceptualize the payoffs and penalties associated with all of the decks and the advantages of selecting from decks C and D.

However, when patients who had experienced frontal lobe damage completed this task, different results emerged. These subjects never showed anticipatory SCRs or adopted a strategy of bypassing the risky A and B decks for the higher-payoff C and D decks. It appeared that the neural circuits enabling messages from the emotional areas of the brain to reach brain areas involved in decision-making were disrupted (Bechara, Damasio, Tranel, & Damasio, 1997; Turnbull et al., 2014).

Behind the Scenes

The findings from the Iowa Gambling Task suggest that in certain situations, the brain is taking in information and making decisions at a pace faster than our conscious awareness can process. This suggests that our hunches that we generally think of as vague and unsubstantiated may be just the opposite—a result of very efficient neural processing occurring at a pace that is difficult for us to keep up with. A gut feeling appears to be an emotional or body perception (indicated by physiological reactions like SCRs) that is being monitored by the brain’s decision-making areas via the establishment of formidable neural networks.

One particular type of neuron in the brain’s neural networks, the von Economo neuron, may be particularly crucial in our ability to make quick intuitive judgments about seemingly random events. Named after the researcher who formally identified the cells in 1925, these bipolar neurons are larger than typical neurons and have two similarly sized dendrites extending from the cell body (Von Economo & Koskinas, 1925; Allman et al., 2010; see Brain Scene Investigation Box Figure 1). Complex information is more likely to be coded in neural networks than in individual neurons. Von Economo neurons and their connections within neural networks seem to play a key role in an individual’s ability to make quick, intuitive assessments of complex situations.

The von Economo neurons, sometimes called spindle cells, are located in the anterior cingulate cortical area and the frontoinsular cortical area of the brain. They are about five times denser in the right hemisphere than in the left hemisphere. In contrast to most other neurons in humans, von Economo neurons appear late in fetal brain development—in the 35th week of pregnancy (Allman, Watson, Tetreault, & Hakeem, 2005; Allman et al., 2011).

Functional magnetic resonance imaging (fMRI) studies yield clues as to which brain regions are involved in intuition. As described in Chapter 1, the fMRI research technique assesses the functions of different brain regions by determining which brain regions are “activated” as human research participants perform a specified (typically cognitive) task. As a participant performs a task, the fMRI technique detects associated changes in the blood flow to different regions of his or her brain. One fMRI study revealed that two brain areas activated during fast-paced decisions based upon “hunches” and “intuitive thinking” are the anterior cingulate and frontoinsular cortical areas, in which von Economo neurons are located (Critchley et al., 2001).

Thus, evidence suggests that during complex intuitive responses, the von Economo neurons in the anterior cingulate and frontoinsular cortical areas are likely engaged. Initial reports that von Economo neurons were found only in the highly evolved brains of humans and great apes solidified our understanding of von Economo neurons as involved in advanced, complex social interactions and interpretations (Allman et al., 2010). However, scientists have recently discovered von Economo neurons in other primate species such as the macaque monkey, as well as in non-primate mammalian species that may have advanced social interactions—specifically, elephants and dolphins (Butti et al., 2009; Evard, Forro, & Logothetis, 2012; Hakeem et al., 2009). Although many questions persist about the von Economo neurons, researchers are identifying neurobiological mechanisms that provide the basis of our intuitions and hunches, which have been difficult to capture in laboratory investigations. More research is certainly needed before we can make more definitive claims about von Economo neurons. I find this research question so intriguing that it inspired my lab to search for von Economo neurons in another mammal with impressive cognitive strategies, the raccoon. Did we find them? Those findings appear in the Epilogue.