Suzanne Egan and Ruth Byrne have found that people interpret counterfactual threats e.g., ‘if you had hit your brother I would have grounded you’ as threatening for the future, whereas they do not interpret counterfactual promises, e.g., ‘if you had mowed the lawn I would have given you 10 euro’ as promising for the future.
Their 2012 article Inferences from counterfactual threats and promises published in Experimental Psychology (59, 4, 227 – 235) begins as follows:
‘The Irish Times on March 11, 2011 reported under the headline ‘‘Man acquitted in case where alleged threat to kill was made in past tense,’’ that a man was acquitted at the special criminal court because his defence counsel argued successfully that he had not threatened to kill or cause serious harm to the defendant’s family because the ‘‘assertion that the accused man told him he ‘could have had’ his father shot and his sister ‘done’ was a statement in the past tense and could not amount to words in law of a threat to future conduct.’’ ‘
and it concludes:
‘Our results suggest that a counterfactual threat, ‘‘I could have had your father killed. . .’’ is interpreted by most ordinary people as threatening for the future, contrary to recent legal argument. In contrast, counterfactual promises appear to exert only a weak illocutionary force; they may serve as a general guide to future behavior (e.g., be good and you will be rewarded) rather than as a specific instruction (e.g., if you mow the grass tomorrow then I will pay you 10 euro).’