statistical power as the reason for the female-only sample because females were argued to experience generally
more intense emotional responsivity. Sex differences in fMRI were specifically examined by Schulte-Ru ¨ther et al.
(2008) who used 12 males with a mean age of 24.4 years ( SD53.0) and 14 females with a mean age of 24.8 years
(SD53.7). Xu et al. (2009) examined ethnic differences with a sample of eight male and nine female Chinese col-
lege students (mean age 523.0 years, SD52.0) and eight male and eight female Caucasian college students
(mean age 523.0 years, SD53.7). Few studies have used adolescent or children samples. Sterzer, Stadler,
Poustka, and Kleinschmidt (2007) used 12 male adolescents with conduct disorder (mean age of 12.75 years,
SEM50.49) recruited from clinics of the Department of Child and Adolescent Psychiatry in Germany and com-
pared this sample with 12 healthy male adolescents (mean age of 12.5 years, SEM50.45). Pfeifer et al. (2008)
used a sample of 16 children (nine boys and seven girls) aged from 9.6 to 10.8 years ( M510.2 years, SD50.4).
Reliability
Activations across the entire brain consistently resulted in positive correlations for lateralized indices of encod-
ing ( r5.82) and recognition ( r5.59)Wagner et al. (2005, p. 126) .
Test/C0Retest
Wagner et al. (2005) investigated test /C0retest reliability of activation patterns elicited in the medial temporal
lobes using fMRI and a verbal episodic memory paradigm over a 7 to 10-month time interval. They reported sig-
nificant test /C0retest coefficients of medial temporal lobe activations for encoding ( r5.41) but not for recognition
(r52.24).
Validity
Convergent/Concurrent
As indicated above in relation to MRI, certain brain regions subserve empathy (e.g., ACC, IFG) and these are
also focused on in fMRI research into empathy. Convergent validity with self-report empathy scales and fMRI
has been obtained. The IRI Perspective Taking subscale correlates positively with activation of a mirror neuron
system for auditory stimuli related to motor execution ( Gazzola et al., 2006 ). Activation in the somatosensory cor-
tex, inferior frontal gyrus, superior temporal sulcus, and middle temporal gyrus were positively correlated with
self-reported cognitive empathy as measured by the IRI Perspective Taking and Fantasy subscales ( Hooker et al.,
2010 ). Activity in the precentral gyrus was also significantly correlated with IRI Empathic Concern and IRI
Personal Distress subscales ( Hooker et al., 2010 ).Sterzer et al. (2007) reported that anterior insula activity was
positively associated with Impulsiveness /C0Venturesomeness /C0Empathy Questionnaire ( Eysenck & Eysenck, 1991 )
scores. Singer et al. (2004) reported that activation in the ACC and left anterior insula was positively correlated
with scores on the BEES (ACC: r5.52; left insula: r5.72) and the IRI Empathic Concern subscale (ACC: r5.62;
left insula: r5.52). A significant correlation ( r5.77) has been found between fMRI medial prefrontal cortex activ-
ity and favorable ingroup biases (ingroup /C0outgroup) in ratings of the amount of empathy felt towards indivi-
duals in pain scenarios (1 5not at all to 45very much ;Mathur et al., 2010 ).Shamay-Tsoory et al. (2005) used
Positrom Emission Tomography (PET) and showed that the cerebellum, thalamus, occipitotemporal cortex, and
frontal gyrus were more strongly activated during an empathy eliciting interview than a neutral interview.
Divergent/Discriminant
Xu et al. (2009) using fMRI showed that Caucasian and Chinese participants who viewed images of faces
receiving a painful injection showed more activity of the ACC and insular cortex if those images depicted people
of their own ethnicity than if they depicted people of another ethnic group. African-American participants have
shown greater activity of the medial prefrontal cortex when viewing members of their same ethnic group than
other ethnic groups ( Mathur et al., 2010 ).
Likewise, sex differences in brain regions activated during fMRI are apparent from various research studies.
For example, Schulte-Ru ¨ther et al. (2008) tested 12 males and 14 females in a picture viewing paradigm.
Participants viewed synthetic fearful or angry faces and were asked to concentrate on their own feelings when
viewing the faces (self-task) or on the emotional state in the target (other-task). Female participants scored more
highly on the BEES and rated the intensity of their own emotions when viewing the stimuli as higher than male
participants. Sex differences in fMRI were found in the comparison of the self-task with a baseline task wherein
females showed stronger activation of the right inferior frontal cortex, right superior temporal sulcus, and right
cerebellum than males. Males showed stronger activation of the left temporoparietal junction than females. In the279 NEUROSCIENTIFIC MEASURES OF EMPATHY
III. EMOTION REGULATION