Difficulty = 1Easy:
 contrast             estimate    SE  df z.ratio p.value
 2reversed - 1quiet    -0.0454 0.223 Inf -0.203  0.9775 
 2reversed - 3forward   0.1417 0.243 Inf  0.582  0.8295 
 1quiet - 3forward      0.1871 0.235 Inf  0.795  0.7064 

Difficulty = 2Hard:
 contrast             estimate    SE  df z.ratio p.value
 2reversed - 1quiet    -0.1266 0.323 Inf -0.392  0.9188 
 2reversed - 3forward  -1.0999 0.389 Inf -2.831  0.0129 
 1quiet - 3forward     -0.9733 0.358 Inf -2.717  0.0181 

P value adjustment: tukey method for comparing a family of 3 estimates 
