Neural correlates of belief- and desire-reasoning in 7- and 8-year-old children: an event-related potential study

Abstract

Theory of mind requires belief- and desire-understanding. Event-related brain potential (ERP) research on belief- and desire-reasoning in adults found mid-frontal activations for both desires and beliefs, and selective right-posterior activations only for beliefs. Developmentally, children understand desires before beliefs; thus, a critical question concerns whether neural specialization for belief-reasoning exists in childhood or develops later. Neural activity was recorded as 7- and 8-year-olds (N = 18) performed the same diverse-desires, diverse-beliefs, and physical control tasks used in a previous adult ERP study. Like adults, mid-frontal scalp activations were found for belief- and desire-reasoning. Moreover, analyses using correct trials alone yielded selective right-posterior activations for belief-reasoning. Results suggest developmental links between increasingly accurate understanding of complex mental states and neural specialization supporting this understanding.

Figure 1

A schematic of the theory of mind Diverse-Desires (left), Diverse-Beliefs (middle), and Diverse-Physical (right) tasks showing examples of information phase (top) and target questions (bottom) as well as sample graphics for both food and toy condition types.

Figure 2

Full-trial analyses topographical maps of the scalp electrical activity at all 128 channels. Maps depict mean amplitude difference for Physical subtracted from Desire (left), Physical subtracted from Belief (middle), and Desire subtracted from Belief (right) in the 200–250 ms (top), the 350–600 ms, 600–800 ms, 800–850 ms, and 850–1400 ms (bottom) post stimulus epochs. Maps are oriented with frontal position up from an overhead scalp view. Darker regions indicate greater negative differences between two conditions. The maps show a clear difference in the 200–250, 350–600, 600–800, and 800–850 ms epochs for the Desire-Physical and Belief-Physical comparisons (Desires and Beliefs more negative compared to Physical) but do not show any clear difference for the Belief-Desire comparison.

Figure 3

Full-trial analysis grand average event-related brain potential waveforms for the Desires (red dotted lines), Beliefs (blue solid lines), and Physical (black dashed lines) conditions from 25 channels selected to encompass locations from left to right and front to back (top to bottom in the grid) over the scalp. The 128 EGI channels can be grouped and labeled in terms of the 10-10 system convention. This figure adopts that more standard convention, with the selected channels reflecting 10-10 labels and positions. The boxed section indicates epochs in which analyses were performed. Waveforms are displayed with positive amplitudes above the axis and negative amplitudes below.

Figure 4

Figure 4a and b. Grand average event-related brain potential waveforms for the Desires (red dotted lines), Beliefs (blue solid lines), and Physical (black dashed lines) for the right mid-frontal 5-channel cluster for full-trial (A. left) and correct-trial (B. right) analyses. The boxed section indicates epochs in which the Beliefs and Desires conditions showed the strongest significant differentiation from the Physical Condition. Waveforms are displayed with positive amplitudes above the axis and negative amplitudes below. Scalp positions for the 5-channel cluster (bold channels) relative to the 5 × 5 grid are shown at the top.

Figure 5

Figure 5a and b. Grand average event-related brain potential waveforms for the Desires (red dotted lines), and Beliefs (blue solid lines) conditions for the right posterior 5-channel cluster for full-trail (A. left) and correct-trial (B. right) analyses. The boxed section indicates the 600–800 ms epoch in which the correct-trial analyses first demonstrated significantly greater amplitude for Beliefs over Desires. Waveforms are displayed with positive amplitudes above the axis and negative amplitudes below. Scalp positions for the 5-channel cluster relative to the 5 × 5 grid are shown at the top.