HBR lays out The Secret Reason Your Employees Won’t Innovate:

After surveying hundreds of employees ranging from managers to stock clerks, Feirong Yuan of the University of Kansas and Richard W. Woodman of Texas A&M found that worries about “image risks” (unfavorable social impressions) significantly diminish workers’ innovativeness. People whose roles don’t explicitly call for innovation believe that coworkers will think negatively of them if they try to come up with better ways of doing things. In some cases, they’re even afraid they’ll “provoke anger among others who are comfortable with the status quo,” Yuan says. 

We have discussed some of the reasons why R&D team members are reluctant to put forward new ideas: Risk averseness and misaligned incentives.  Clearly something R&D managers should be consciously changing:

But leaders can have a big impact on this problem, the researchers report in the Academy of Management Journal. Perceived organizational support for innovation significantly reduces workers’ view of the social riskiness. The key is to create a sense of psychological safety: Provide an environment in which differences are tolerated and people feel free to approach problems in new ways.