Brain–behaviour associations: Adult solo play and joint Play.

(a and b) Mean time-lagged cross-correlations examining the relationship between EEG power and attention for parent solo play and parent joint play. (Fig 4A is identical to Fig 2B but scaled to be equivalent to Fig 4B to allow for comparison.) (c) Bar chart comparing the frequency of the peak association between EEG power and looking behaviour for parents in the solo play and joint play conditions. * indicates the results of the significance calculations, conducted as described in the main text. (d) Line plot showing cross-correlation between EEG power and visual attention for just the frequency ranges identified from the cluster-based permutation test as showing marked effects in both conditions (parent solo play: 6 Hz–12 Hz; parent joint play: 2 Hz–8 Hz). Red shows the joint play condition, and blue the solo play condition. Shaded areas show interparticipant variance (standard errors). (e) Results of the cluster-based permutation statistic for parent joint play. Yellow squares indicate time × frequency points of significant cross-correlations. The underlying data for this figure can be found in S1 Text and S1 Data.