The effect of number of options on choices involving delayed causation.

A video game was adapted to investigate the effect of the number of alternatives on causal judgment in a complex environment involving targets with delayed outcomes. Participants were presented with groups of potential targets. Each target (the candidate cause) fired at random relative to the others, with one target in each group causing a delayed explosion (the effect).The participants were tasked with discriminating which of the potential targets was producing the effect. Experiment 1 revealed a main effect of delay on discriminability but no effect of the number of alternatives. However, latencies did increase as the number of alternatives increased, suggesting that discriminability was maintained by compensating with longer observation times. But, a similar increase in latency for longer delays did not offset the detrimental impact of an increase in cause-effect delay. Experiment 2 replicated the outcome under conditions in which participants were always required to observe for 16 s before making a decision; under the most difficult conditions, however, the limited viewing time started to reveal an effect of the number of alternatives on the participants' ability to discriminate a true cause from foils. Evidence suggests that participants' decisions were determined primarily by differences in the number of cause-effect contiguities experienced for the true cause versus the foils.