Table 3.

The distinction between impulsive and risk-taking choice across cognitive neuroscience and personality literatures

	Impulsivity	Risk-taking
Classic personality	Impulsivity	Venturesomeness
Current personality	Constraint-disinhibition	Extraversion/sensation-seeking
Preferred reward choice	Soonest/immediate	Biggest
Computational Parameter	Time	Reward size
Devalued parameter	Reward size	Reward/punishment uncertainty
Reflection	No	Neutral (yes or no)
Mathematical function	Temporal discounting	Probability discounting
Magnitude effect rewarda	forward (small>large)	backward (large>small)
Variation across outcomesb	yes	no
Developmental coursec	linear	non-linear
Heuristic pharmacologyd	Serotonergic tone	Dopaminergic tone
Meta-traitse	Stability	Plasticity

For more discussion see reviews by L. Green and Myerson (2010) and Evenden (1999). The classic personality model is that of Eysenck (Eysenck, 1993); the contemporary rendition is taken from the meta-analysis by (Sharma et al., 2014).

^a= magnitude effect means larger rewards are discounted less steeply than smaller rewards over time (‘forward’ effect); but more steeply over odds against their occurrence (‘backward’ effect). If they are governed by the same system then this reversal is puzzling because longer delay is generally correlated with odds against occurrence.

^b=monetary rewards and consumables (e.g., food) have different discounting rates for temporal discounting but the same discounting rates for probability (or odds against)(Estle, Green, Myerson, & Holt, 2007; Mitchell et al., 2015).

^c=response control develops with linear growth to adulthood, whereas risk-taking peaks in adolescence and then declines in a nonlinear path (Shulman et al., 2016).

^d=A psychobiological model proposes that Constraint (but not sensation seeking or risk-taking) is related to serotonergic tone (Carver, Johnson, & Joormann, 2009; Depue & Spoont, 1986; Evenden, 1999) while venturesomeness reflects a dopaminergically-mediated approach system (Depue and Collins (1999). Neurotransmitter systems involve complex feedback loops that cannot be reduced to a single chemical, but these emphases are heuristic.

^e=For review see (DeYoung, 2011).