What does the sucking reflex respond to?

The sucking reflex is primarily a response to tactile stimulation, specifically when an infant's cheeks or the sides of their lips are touched. This reflex is critical for feeding, as it helps infants latch onto the breast or bottle to suck and obtain milk. When an infant feels stimulation in these areas, it triggers an instinctive rejection of the nipple or bottle, ensuring they can feed effectively.

The other options do not elicit the sucking reflex. Bright lights may cause various visual responses, but they don’t directly stimulate the sucking mechanism. Sounds made by caretakers may engage the infant’s auditory senses and encourage recognition of voices but do not prompt the sucking reflex. Similarly, while temperature changes can influence an infant's comfort and feeding patterns, they do not specifically trigger the sucking response. Thus, tactile stimulation of the cheeks or lips is distinctly associated with the sucking reflex in infants.