 This notion of reduction of metabolic cost may be disputed by a study done by Gard and Childress (1997),Gard, S. A. , Childress, D. S. (1997).
<fluency>  This notion of reduction of metabolic cost may be disputed by a study done by Gard and Childress (1997),Gard, S. A. , Childress, D. S. (1997).
 This notion of reduction of metabolic cost may be disputed by a study done by Gard and Childress (1997),Gard, S. A. ; Childress, D. S. (1997).