Having a phone conversation delays but does not disrupt cognitive mechanisms

Previous research has shown that talking on a mobile phone leads to impairments in a number of cognitive tasks. However, it is not yet known whether the act of conversation disrupts the underlying cognitive mechanisms (the Cognitive Disruption hypothesis) or leads to a delay in response due to a limit on central cognitive resources (the Cognitive Delay hypothesis). We investigated this here using two cognitive search tasks that investigate spatial learning and time-based selection: Contextual Cueing and Visual Marking. In Contextual Cueing, responses to repeated displays are faster than those to novel displays. In Visual Marking, participants prioritize attention to new information and deprioritize old, unimportant information (the Preview Benefit). Experiments 1 to 3 investigated whether Contextual Cueing occurred while people were engaged in a phone conversation, whereas Experiments 4 to 6 investigated whether a Preview Benefit occurred, again while people were engaged in conversation. The results showed that having a conversation did not interfere with the mechanisms underlying spatial learning or time-based selection. However, in all experiments there was a significant increase in response times. The results are consistent with a Cognitive Delay account explaining the dual-task cost of having a phone conversation on concurrent cognitive tasks