Irrelevant speech and indoor lighting: effects on cognitive performance and self-reported affect

This study examined the disruption of cognitive performance by ecologically valid, office and school like settings with warm‐ or cool‐white lighting and silence or meaningful, irrelevant, conversational speech, and whether any such susceptibility was attributable to the changes in affective states. The study aims to address the lack of data on combined impact of noise and light on humans in previous research and to complement findings of irrelevant sound effect in list memory studies. No interactions between noise and light were shown, but there were main effects of noise and light on long‐term memory recall and of noise on self‐reported affect. Cool‐white compared to warm‐white lighting impaired the long‐term memory recall of a novel text. Learning from this text was, in addition, disrupted by meaningful, irrelevant, conversational speech: an impact that was not mediated by affect. The obtained noise effect suggests that the meaning in irrelevant sound was processed, to some extent, semantically by the subjects, which disrupted their performance in a cognitive task that also involved processing of meaning. Copyright © 2002 John Wiley & Sons, Ltd.