Although a population bias toward right-hand preference is observed at the early stage of grasping, hand preference fluctuates in infancy. Given these fluctuations, one can wonder whether testing a young infant on a single occasion gives reliable results of its handedness. Very few studies have evaluated short-term test-retest reliability. This was the goal of this study in which 21 infants aged 9–15 months were tested for handedness every day for a total of 5 sessions. The infants were given a classical handedness baby test. Their handedness index (HI) and their category of handedness were compared across sessions.

The results show that at the group level the distribution of handedness does not differ significantly across the five sessions. At the individual level, only 19% of infants were categorized as right-handed at all five sessions while 52.4% were consistent in using more one hand than the other across the five sessions (right hand: 47.6%). Most of the fluctuations across sessions occurred between being lateralized and non-lateralized rather than between being right-handed and left-handed.

These figures indicate that testing handedness at that age gives fairly reliable results in terms of direction of hand preference, but less so in terms of degree.

尽管在抓握的早期阶段观察到人口偏向右手偏爱，但婴儿期手偏爱却有所波动。鉴于这些波动，人们可能想知道一次测试一个婴儿是否能获得可靠的惯用性结果。很少有研究评估短期重测信度。这是本研究的目标，其中每天对21名9-15个月大的婴儿进行惯性测试，共5次。婴儿接受了经典的惯性测试。在各个会话中比较了他们的惯用度指数（HI）和惯用度类别。

结果表明，在小组级别上，五个阶段的惯用性分布没有显着差异。在个人层面上，在所有五个时段中，​​只有19％的婴儿被归为右手，而在五个时段中，​​有52.4％的一只手的使用率高于另一只手（右手：47.6％）。跨会议的大多数波动发生在偏侧和非偏侧之间，而不是右撇子和左撇子之间。

这些数字表明，在该年龄段的测试习惯性在手偏爱的方向上给出了相当可靠的结果，但在程度上却不那么可靠。