Table 1.

Logical forms used in stimuli, with sample arguments

Validity	Cognitive load	Formal structure	Block argument examples	Nonsense phoneme argument examples
Valid	Low	p → ¬q p ¬q	If the block is green then it is not small. The block is green. —————————— The block is not small.	If the hak is kig then it is not gop. The hak is kig. —————————— The hak is not gop.
Valid	Low	(p˅q) → ¬r p ¬r	If the block is either heavy or large then it is not blue. The block is heavy. —————————— The block is not blue.	If the hak is either kig or ik then it is not gop. The hak is kig. —————————— The hak is not gop.
Valid	High	(p˅q) → ¬r r ¬p	If the block is either red or square then it is not large. The block is large. —————————— The block is not square.	If the hak is either ag or bub then it is not frek. The hak is ag. —————————— The hak is not frek.
Valid	High	p → ¬q q ¬p	If the block is large then it is not blue. The block is blue. —————————— The block is not large.	If the hak is ag then it is not bub. The hak is bub. —————————— The hak is not ag.
Invalid	Low	(p˄q) → ¬r p ¬r	If the block is both blue and square then it is not large. The block is blue. —————————— The block is not large.	If the tep is both kig and ob then it is not plob. The tep is kig. —————————— The tep is not plob.
Invalid	Low	¬p → (q˅r) ¬p q	If the block is not red then it is either square or small. The block is not red. —————————— The block is square.	If the hak is not trum then it is either stas or plob. The hak is not trum. —————————— The hak is stas.
Invalid	High	(p˄q) → ¬r r ¬p	If the block is both square and small then it is not blue. The block is blue. —————————– The block is not square.	If the tep is both grix and ag then it is not ik. The tep is ik. —————————— The tep is not grix.
Invalid	High	¬p → (q˅r) ¬q p	If the block is not blue then it is either small or light. The block is not small. —————————— The block is blue.	If the tep is not trum then it is either frek or ob. The tep is not frek. —————————— The tep is trum.