A weakness of split-brain?

-causal relationship hard to establish -Behaviour in Sperry's split-brain ppts were compared to a neurotypical control group. An issues though is that none of the ppts in the control group had epilepsy -Significant bc this was a confounding variables, differnece betwen the groups could have been a result of epilepsy rather than split brain -means that some of the unique features of the split-brain ppts' congitive abilites may have been due to their epilespsy.