a weak trendp = . 054
We found only a weak trend for an effect of age on the number of training sessions needed ( χ 2 = 0.051, df = 1, p = . 054), and again no effect of sex ( χ 2 = 0.497, df = 1, p = . 495; see Table S6 ). fMRI training and testing To date, 21 (including one deaf dog) out of 24 dogs were trained to be scanned while they stayed unrestrained and motionless with their head in the human knee coil in the MRI scanner bore.