Task demands and experimenter effects do not refute scanning and rotation experiments:

• The claim that task demands caused subjects simulate how they would behave with real objects is disconfirmed by experiments that make no mention of physical motion. References to "physical motion" and "scanning" are replaced by phrases such as "glance up" and "shift attention".

• The claim that subjects give answers they think the experimenters want to hear is disconfirmed by the fact that subjects often give responses that the experimenters didn’t anticipate. These responses could not have been suggested by the experimenters.

Stephen Kosslyn, Stephen Pinker, George E. Smith, and Steven P. Schwartz (1979).