(b)Three target conditions 



(c)Time Line 



< a > Four cue conditions 



Cue 



4-4-4-4-4- -k->4—*-* --4 



-►-►-►-►-► 4-i — M-«- ► -- 



congruent incongruent Neutral 



□ □ m g 



no cue center cue double cue spatial cue 



(d)Three subtractions 



ALERTING = NO CUE RT - DOUBLE CUE RT 



ORIENTING = CENTER CUE RT - SPATIAL CUE RT 



CONFLICT = INCONGRUENT TARGET RT - CONGRUENT TARGET RT 



Fig. 6. A schematic of the attention network test, (a) Various cues that inform 

 people about the location and time of the target, (b) congruent and incongruent target 

 conditions, (c) time line for the cue and target, and (d) three subtractions that indicate 

 the quantitative efficiency of each network. 



in children with ADHD, was not associated with attentional diffi- 

 culties. Moyzis and associates showed that the 7 repeat was one of 

 some 300 genes influencing neural function (Wang et al., 2006) that 

 gave evidence of being positively selected in recent human evolution 

 (Ding et al., 2002). These findings suggested that the association of 

 the 7 repeat with ADHD might have been via its relationship with 

 sensation seeking, rather than through poor attention. We believe 

 that the data provided below from our current longitudinal study 

 (see fig. 10) might help resolve this paradox and suggest why it is 

 that some genetic alleles like the 7 repeat may increase their fre- 

 quency in human evolution. 



Posner et al. (2007) have recently summarized evidence for sev- 

 eral dopamine and serotonin-related genes that have specific rela- 

 tionships to the executive attention network. It is now clear that part 

 of the difference among individuals on ANT scores is related to 



10 



