Extremist positions as an antidote to boredom and lack of curiosity.

 Hmm.  From Going to political extremes in response to boredom by Wijnand A.P. Van Tilburg and Eric R. Igou.  From the Abstract:

Boredom makes people attempt to re‐establish a sense of meaningfulness. Political ideologies, and in particular the adherence to left‐ versus right‐wing beliefs, can serve as a source of meaning. Accordingly, we tested the hypothesis that boredom is associated with a stronger adherence to left‐ versus right‐wing beliefs, resulting in more extreme political orientations. Study 1 demonstrates that experimentally induced boredom leads to more extreme political orientations. Study 2 indicates that people who become easily bored with their environment adhere to more extreme ends of a political spectrum compared with their less easily bored counterparts. Finally, Study 3 reveals that the relatively extreme political orientations among those who are easily bored can be attributed to their enhanced search for meaning. Overall, our research suggests that extreme political orientations are, in part, a function of boredom's existential qualities.

I have long argued that extremism, particularly signaling and discretionary extremism, is to some degree a function of prosperity.  The more comfortable you are and the more secure your financial position, the easier it is, especially when younger, to take risks.  One form of risk is extremist political or ideological positions.  

That is not incompatible with the boredom thesis advanced here.  Boredom is potentially the causal mechanism arising as a product of prosperity and financial security.  

I can't get access to the full paper so I have no visibility into the effect size.  Perhaps this is much ado about almost nothing.  But an interesting hypothesis to keep in mind.