Selection history modulates the limit of visual awareness in color perception

Among studies on the limit of conscious representation of color at a given instant, some have shown evidence of momentary awareness of only a single color, while others have not, leading to uncertainty about the factors that influence the limit. In two experiments, we explored the role of selection history, or recent experience with a trial, which is known to influence the representations of task stimuli and responses. Two color patches were briefly displayed either simultaneously or sequentially. In Experiment 1, we presented the two types of trials either in separate blocks or in interleaved couplets. In the former case, participants could deploy optimal attentional control setting in response to different types of trials with little cost by using recent experience with a preceding trial and prior knowledge. In the latter case, reconfiguring attentional control setting after each trial would be costly. In Experiment 2, we mixed the two types of trials randomly within a block during testing, but re-grouped them in data analyses such that the same type of trials was either repeated or not repeated. The results show that accuracy was comparable between the simultaneous and sequential trials in the block condition in Experiment 1 and in the repeat condition in Experiment 2, suggesting that two colors were perceived at a time. These results indicate that selection history plays an important role in the limit of visual awareness in color perception and that the finding of single-color perception reported in previous research might not be a general phenomenon.