Dipartimento di Studi Umanistici, Università degli Studi di Ferrara, Ferrara, Italy.
Dipartimento di Neuroscienze, Imaging e Scienze cliniche, Università di Chieti-Pescara G. d'Annunzio, Chieti, Italy.
PLoS One. 2022 Feb 4;17(2):e0263510. doi: 10.1371/journal.pone.0263510. eCollection 2022.
The last decades have seen an increasing interest in the phenomenon of yawning and the dynamics of its modulation, yet no widespread consensus exists on its origins and potential functions. Although most scholars have focused on its potential physiological functions, e.g., related to thermoregulation, arousal modulation or cortisol levels and distress, an emerging line of research has been also investigating the social implications of yawning, including its hypothesized relationship with empathy. In order to explore the dynamics of yawning modulation in infants, we investigated whether a social perturbation-like the one induced by the Face to Face Still Face paradigm, a procedure designed to assess socio-emotional regulation in infants-affects yawning and self-touch hand movements behavior in three-months old infants. As the Still Face episode represents a source of mild distress, we hypothesized that during this phase yawns would be more frequent. Moreover, through the use of path analysis, we investigated potential dynamics of facilitation, inhibition or covariance between the frequencies of these behavioral patterns. Our results showed a sharp increase in self-touch hand movements as well as in the likelihood of yawning during the stressful phase of the procedure (still-face) compared with the two minutes of face-to-face interaction and the reunion episode. Regressions also showed a higher incidence of yawns among girls, consistently with the hypothesis that the analysis of yawning behavior might capture subtle differences in regulatory strategies of infants, possibly related to the transient sex-specific activation of the hypothalamic-pituitary-gonadal axis known as mini-puberty. The path analysis showed a greater consistency between the frequencies of self-touch hand movements during the three episodes of the procedure, compared with yawning. This finding could be a result of distinct yawning-regulating mechanisms being at play in different conditions, e.g., a modulation related to stress and one to social interaction. Taken together, these results suggest that human yawning regulation is an irreducibly complex and multifaceted phenomenon since early age. Moreover, the gender differences highlighted might suggest an early diversification in yawning modulation.
过去几十年，人们对打哈欠现象及其调节动态越来越感兴趣，但对于其起源和潜在功能尚未达成广泛共识。尽管大多数学者都集中在其潜在的生理功能上，例如与体温调节、觉醒调节或皮质醇水平和压力有关，但新兴的研究方向也在研究打哈欠的社会意义，包括其与同理心的假设关系。为了探索婴儿打哈欠调节的动态，我们调查了类似社会干扰的因素（如面对面的静止脸范式引起的干扰）是否会影响三个月大婴儿的打哈欠和自我触摸手运动行为。由于静止脸阶段代表了轻度压力源，我们假设在此阶段打哈欠会更加频繁。此外，我们通过路径分析，研究了这些行为模式的频率之间促进、抑制或协变的潜在动态。我们的结果表明，与面对面互动和团聚阶段相比，在程序的紧张阶段（静止脸），自我触摸手运动以及打哈欠的可能性急剧增加。回归分析还显示，女孩打哈欠的发生率更高，这与打哈欠行为分析可能捕捉到婴儿调节策略的细微差异的假设一致，这可能与已知的下丘脑-垂体-性腺轴短暂的性别特异性激活（微小青春期）有关。路径分析还表明，与打哈欠相比，在程序的三个阶段中，自我触摸手运动的频率之间具有更大的一致性。这一发现可能是由于不同条件下存在不同的打哈欠调节机制造成的，例如与压力相关的调节和与社会互动相关的调节。总之，这些结果表明，人类打哈欠的调节是一个从早期就具有复杂和多方面性质的现象。此外，突出的性别差异可能表明打哈欠调节的早期多样化。
