Suter Susanne E, Huggenberger Harriet J, Richter Steffen, Blumenthal Terry D, Schachinger Hartmut
sesam - Swiss Etiological Study of Adjustment and Mental Health - National Centre of Competence in Research, Institute of Psychology, University of Basel, Birmannsgasse 8, Postfach, CH-4009 Basel, Switzerland.
Int J Psychophysiol. 2009 Oct;74(1):53-7. doi: 10.1016/j.ijpsycho.2009.07.002. Epub 2009 Jul 17.
Cradling represents a unique type of mother-infant interaction. A bias towards left side cradling of infants and baby-like dolls has been demonstrated in human females, irrespective of handedness. One explanation for this behavioural bias involves right hemispheric specialisation of decoding visual, acoustic, and tactile emotional signals of left perceptual field origin. This implies that emotional signals from the child could have a greater impact on the caregiver's affective state when originating in the left than right perceptual fields. This may represent a key reinforcing mechanism responsible for left side cradling, but this has never been tested. In the present study, sixty-two never-pregnant female volunteers held an appetitive baby-like doll on the left or the right arm while reflexive startle eye blinks to binaural acoustic noise probes, as well as heart rate variability (HRV), were assessed. During left side cradling startle eye blink magnitude was attenuated, and low frequency HRV was decreased while high-frequency HRV was significantly increased. Attenuation of startle occurs in positive affective contexts, and high-frequency HRV is a reliable marker of vagal activity known to increase in appetitive, non-stressful contexts. Thus, our results suggest that appetitive infant signals have more positive effects on affective processes of the female caregiver when presented in her left perceptual fields.
怀抱是一种独特的母婴互动形式。研究表明，人类女性对婴儿和类似婴儿玩偶倾向于使用左侧怀抱，无论其惯用手是哪只。对此行为偏差的一种解释涉及右半球在解码源自左感知场的视觉、听觉和触觉情感信号方面的特殊化。这意味着，当孩子的情感信号源自左侧而非右侧感知场时，对照顾者情感状态的影响可能更大。这可能是左侧怀抱背后的一种关键强化机制，但尚未得到验证。在本研究中，62名未怀孕的女性志愿者分别用左臂或右臂抱着一个可爱的类似婴儿的玩偶，同时评估她们对双耳听觉噪声探测的反射性惊吓眨眼反应以及心率变异性（HRV）。在左侧怀抱时，惊吓眨眼幅度减弱，低频HRV降低，而高频HRV显著增加。惊吓反应减弱发生在积极情感情境中，高频HRV是迷走神经活动的可靠指标，已知在愉悦、无压力的情境中会增加。因此，我们的结果表明，当可爱的婴儿信号出现在女性照顾者的左侧感知场时，对其情感过程有更积极的影响。
