The personality trait of novelty seeking (NS) has been associated with the long variant of the dopamine D4 receptor (L-DRD4) VNTR polymorphism. This is the first study to examine the influence of L-DRD4 polymorphism on some of the cognitive (i.e. decision making) and emotional underpinnings of the NS phenotype. One hundred and eighteen healthy males grouped in a L-DRD4 (n=24) and a S-DRD4 (n=94) group, completed multimodal assessment for personality, planning for problem solving and decision making. Two age-matched L-DRD4 and S-DRD4 sub-samples (n=17 each) entered and completed emotional processing using startle modulation by affective pictures. ANOVAs showed that L-DRD4 individuals had higher NS, made more risky choices and won less money in the decision making task, but had intact planning for problem solving. They also had reduced startle reactivity and late startle modulation by both pleasant and unpleasant pictures. Early, attentional startle modulation by the affective pictures was intact. NS correlated negatively with startle reactivity and performance in the emotional decision task. These results suggest that the L-DRD4 polymorphism is associated with high NS and risk taking, under-reactivity to unconditioned aversive stimuli, constricted emotional responses but preserved attentional processing of emotional stimuli and efficient problem solving. These results extend animal evidence on DRD4-mediated control of decision making and emotional processing to humans. The proposed role of the NS phenotype in human evolution and in disorders of impulsivity is discussed under the light of the present findings.