You have to feel a little sorry for the four male authors. They spent countless hours scouring twenty-plus-year-old research to cite sources and claim these articles say that men don't care about the environment. One seventeen-year-old paper is cited as saying that men "leave a smaller carbon footprint," but all it actually suggests is that out of four specific European countries, single-man households in Greece and Sweden use more energy (in statistically significant amounts) than single-women households in those two countries.
In Study 4, I don't see how anyone could draw a "green" association with a lamp, battery, or backpack. All of these products have tradeoffs.
In Study 5, note that the female cohort in declined in "green"-ness for the manly packaging. This suggests to me that the control was probably somewhat feminine, and people are more likely to prefer products that correspond to their gender norms -- whether or not those products have an underlying pro-environmental utility.
> Although only mem [sic] had been recruited to participate in [Study 4], 14 participants reported their gender as female and were therefore excluded.
WTF kind of methodology is that?
Finally, I note that the archetype of a manly conservationist is strong in the USA. Teddy Roosevelt. John Muir. Ralph Waldo Emerson. Ansel Adams. These people did more than carrying a disposable shopping bag to Whole Foods, and selecting the "green" backpack.