Prior research has demonstrated that perceptual training can improve the ability of healthcare trainees in identifying abnormalities on medical images, but it is unclear if the improved performance is due to learning or attentional shift—the diversion of perceptional resources away from other activities to a specified task. Our objective is to determine if research subject performance in perceiving the central venous catheter position on radiographs is improved after perceptional training and if improved performance is due to learning or an attentional shift. Forty-one physician assistant students were educated on the appropriate radiographic position of central venous catheters and then asked to evaluate the catheter position in two sets of radiographic cases. The experimental group was provided perceptional training between case sets one and two. The control group was not. Participants were asked to characterize central venous catheters for appropriate positioning (task of interest) and to assess radiographs for cardiomegaly (our marker for attentional shift). Our results demonstrated increased confidence in localization in the experimental group (p-value <0.001) but not in the control group (p-value  =  0.882). The ability of subjects to locate the catheter tip significantly improved in both control and experimental groups. Both the experimental (p-value  =  0.007) and control groups (p-value  =  0.001) demonstrated equivalent decreased performance in assessing cardiomegaly; the difference between groups was not significant (p-value  =  0.234). This suggests the performance improvement was secondary to learning not due to an attentional shift.