scales. Factor analysis produces common factors, which, like ef- 

 fortful control, summarize several of the scales. 



Effortful control has been linked to brain areas involved in self- 

 regulation by imaging studies (Whittle, 2007). Whittle had 155 ad- 

 olescents fill out a temperament scale (Ellis and Rothbart, 2001 ) and 

 also measured the size of different brain structures and their activity. 

 The results of her study are shown in figure 5. She found that the 

 dorsal anterior cingulate size was positively correlated to effortful 

 control and that the ventral anterior cingulate activity was negatively 

 related to effortful control. The reciprocal relation between the ven- 

 tral and dorsal cingulate has also been reported in other imaging 

 studies (Drevets and Raichle, 1998). 



Attention Network Test 



In our work we have used the Attention Network Test (ANT) to 

 examine the efficiency of brain networks that underlie three func- 

 tions of attention: alerting, orienting and executive attention (Fan et 

 al., 2002). The task examined by ANT, illustrated in figure 6, re- 

 quires that the person press one key if the central arrow points to 

 the left and another if it points to the right. Conflict is introduced 

 by having surrounding flankers either point in the same (congruent) 

 or opposite (incongruent) condition. Cues presented prior to the tar- 

 get provide information on either where or when the target will 

 occur. The reaction times for the separate conditions shown in figure 

 6 are subtracted (see bottom of fig. 6) to provide three numbers that 

 represent the skill of each individual in alerting, orienting and ex- 

 ecutive networks. In a sample of 40 normal persons (Fan et al., 

 2002) we found each of these numbers to be reliable over repeated 

 presentations. In addition, we found no correlation among the num- 

 bers. An analysis of the reaction times for this task shows significant 

 effects for cue type and for the type of target. There were only two 

 small interactions that indicated some lack of independence among 

 the cue conditions. One of these interactions was that orienting to 

 the correct target location tended to reduce the influence of the sur- 

 rounding flankers. In addition, omitting a cue, which produces rel- 

 atively long reaction times, also reduces the size of the flanker in- 



