From the actual paper: "With this in mind, an in vivo study was designed to determine the effects of these MPs [microplastics] in a rodent model (Figure 2A). Following a 3-week exposure to PS-MPs, C57BL/6J mice were tested in a series of behavioral assays including the open-field and light–dark preference tests. Both assays showed significant changes in parameters such as distance traveled, rearing activity, and duration in the center between the control and the exposed groups for both old and young mice (Figure 3 and Figure 4). Overall, these changes seemed to be more pronounced in older animals, which may be due to age-related dysfunction exasperating the effects of the PS-MPs on behavioral performance (Figure 3D,H,L and Figure 4D,F). The behavioral changes exhibited by the young mice, however, suggest that even without increased age as a co-variable, PS-MPs can induce altered behavior in rodents after just 3 weeks of exposure (Figure 3B,F,J and Figure 4C,E)."

Rather scary if you ask me...slight behaviour changes in a massive global population such as humans can cause us to make societal level mistakes that could be fatal.