|dc.description.abstract||Information processing biases favouring self- compared to other-referential and positive compared to negative stimuli are theorized to be healthy, adaptive outcomes of well-regulated attention. Within the lab, self-referential information modulates neural encoding of affective trait adjectives and neutral faces as indicated by enhanced event related potential (ERP) amplitudes (i.e., the late positive potential; LPP). Enhanced LPP amplitudes during stimulus encoding in a self- compared to other-relevant context is thought to reflect increased sustained attention following motivationally relevant information, which also supports memory performance for information presented in a self- compared to other-referential context (hereafter the self-referential bias). Similarly, positive compared to negative trait-adjectives are also preferentially attended to (as reflected by enhanced LPP amplitudes) and consequently better remembered (hereafter the positivity-bias), although these findings are mixed. Across the three studies presented in this thesis, I examined how the self-referential and positivity biases modulate the encoding and memory for social information in adults and children, focusing on the LPP waveform and incidental memory performance. I also examined how individual differences in children’s biases are related to temperament and observed conversational styles with unfamiliar peers.
In Study 1, I examined how self- compared to other-referential positive and negative cues from social contextual primes (e.g., “She thinks you/he are/is amazing”) modulated adult LPP amplitudes and subjective ratings towards neutral faces. For the first time, I also examined incidental memory for the trait adjectives embedded within the primes, rather than the stimuli which undergo a subjective rating (i.e., the faces), as is done in the majority of past studies. Replicating previous findings, neutral faces following self- compared to other-referential primes were rated as more arousing and elicited stronger feelings (i.e., more positive and more negative). Subjective arousal was also greater for neutral faces following negative relative to positive social primes, particularly when the primes were about oneself rather than someone else. Faces primed by a self-referential social statement also elicited larger LPP amplitudes relative to faces primed by other-referential statements. However, there was no effect of valence, nor an interaction between referential and valence cues on ERPs. These results were interpreted to reflect heightened attention following a self-referential cue regardless of valence. It was therefore unsurprising that memory was improved for trait adjectives that were presented in a self- compared to an other-referential contextual prime. This novel finding was interpreted to reflect prioritized processing of incidentally encoded self-relevant information which does not necessarily undergo a task-related behavioural response.
While the self-referential and positivity biases have been explored extensively within adults, it remains unclear how children encode self- compared to other-referential trait adjectives across the LPP. In Study 2, I examined 9–12-year-old children’s LPP responses during the encoding of trait adjectives in a Self-Referential Encoding Task (the SRET), as well as their incidental memory for those trait adjectives. The SRET requires participants to behaviourally endorse or reject positive and negative trait adjectives as they relate to the self (self-referential) or someone else (other-referential). Incidental memory is then tested to determine how referent and valence cues modulate memory performance. Results revealed enhanced LPP amplitudes for trait adjectives presented in a self- compared to an other-referential condition; however, there was no effect of valence, nor an interaction, across the LPP. This is the first study to examine child ERP responses to self- compared to other-referential cues, and these results suggest that 9-12 year old’s encode self-referential cues in a similar pattern across the LPP relative to adults. Interestingly, there was no clear effect of referent or valence cues on children’s memory, with memory performance being dependent on the block order in which referent cues were presented. This pattern across memory is discussed in the framework of different consolidation mechanisms for valence cues depending on whether the information is self- or other-relevant.
The final goal of my thesis was to examine whether individual differences in children’s self-referential and positivity biases found in controlled lab settings (i.e., from the SRET) are related to children’s temperament (surgency, effortful control) and in vivo social behaviours. I developed a novel coding scheme to capture indices of the self-referential bias and the positivity-bias based on the content of children’s conversations with an unfamiliar peer. Results revealed that higher effortful control was associated with a larger memory bias for positive relative to negative trait adjectives, supporting the role of control processes in children’s memory performance for positive information. While no other hypothesized associations were supported, this study sets the stage for future work to explore the translational implications of individual differences in self-referential and valence-based biases for social development.
The results of these three studies are discussed in terms of how the self-referential and positivity biases influence social development. We now know that the self-referential bias develops early and is expressed similarly across the LPP between adults and 9-12-year-old children. This enhanced attention improves subsequent memory for self-referential information, although memory is influenced by task parameters. I did not find any support for a positivity bias across neural encoding and memory, which questions its reliability and suggests this bias is task dependent. Despite the relative inconsistency of the positivity-bias in memory, children’s Effortful Control was associated with individual differences in one’s positive relative to negative memory performance. Together, these findings suggest that self-referential cues increase sustained attention at encoding which may have implications for social development in general, whereas valence processing modulates attention and behaviour differently depending on the situation in which they are experienced.||en