In the experimental studies of the abstract conditional statement 4 tasks and 3 types of negatives are used, that is, 12 possible experimental layouts. Only the selection task was properly investigated with all the three negatives. In this study the author runs the missing experiments. Waiting biconditional responses for theoretical reasons, he also investigates the performance of the participants on definitely biconditional problems in selection task. Based on the 8 experiments of which 2 are reported in detail, the participants predominantly interpret the conditional statement as biconditional. The selection task demonstrably hides the biconditional inferences. The interpretation inherently relates to the results of the experiments used to demonstrate the suppression of valid inferences and based on an experiment can be extended towards the interpretation of thematic tasks evoking the P and not-Q response.