Differences in Behavior and Brain Activity during Hypothetical and Real Choices

Abstract

Real behaviors are binding consequential commitments to a course of action, such as harming another person, buying an Apple watch, or fleeing from danger. Cognitive scientists are generally interested in the psychological and neural processes that cause such real behavior. However, for practical reasons, many scientific studies measure behavior using only hypothetical or imagined stimuli. Generalizing from such studies to real behavior implicitly assumes that the processes underlying the two types of behavior are similar. We review evidence of similarity and differences in hypothetical and real mental processes. In many cases, hypothetical choice tasks give an incomplete picture of brain circuitry that is active during real choice.

Keywords: affective realism; choice; decision making; decision neuroscience; hypothetical bias; valuation.

Figure 1.. How Stimuli Are Hypothesized to Vary in Naturalistic Intensity and Evoked Neural Mechanisms.

The stylized graph shows naturalistic intensity on the y axis, extending from low intensity in a controlled laboratory setting to the higher intensity in natural real-world settings. Icons representing some of the studies described in this paper are all plotted low on the y axis, but different laboratory paradigms could have differing degrees of naturalistic intensity. The x axis illustrates how some laboratory stimuli and tasks (such as real vs. hypothetical choice) will evoke different neural mechanisms. The graph illustrates the hypothesized view that many laboratory tasks are low in intensity and evoke only a subset of mechanisms, compared to more realistic choices, which are higher in intensity and evoke a larger set of mechanisms. Note that the positions of the icons and the trajectories (broken lines) do not plot actual numerical measures of intensity or mechanisms (although measures of those variables could be constructed, in principle, for some paradigms with gradation in realism).

Figure 2.. Neural Circuitry of Imagination Network.

Using Neurosynth ([67]; http://neurosynth.org), we identified 29 studies that used imagination or prospection of future events. This identified core brain regions including the posterior cingulate cortex (PCC), posterior hippocampus (pHipp), and ventromedial prefrontal cortex (mPFC). These regions have been implicated in the resting state, mind wandering, and imagination, respectively. Colored regions are those identified by forward inference (blue) or reverse inference (red). Forward inference is based on the relative frequency of studies that use a functional term (imagination), which also have activation in an area (i.e., how many studies which describe imagination find activation in the pHipp?) Reverse inference is based on the relative frequency of studies, which have an activation in a region and also use a functional term (i.e., how many studies which show activation in the pHipp say they are observing imagination?).