Researchers studying newborns use __________, or the decrease in the response to a stimulus that occurs after repeated presentations of the same stimulus, as an indicator of a baby's interest.

Habituation is a fundamental psychological term that describes a decrease in an organism's response to a stimulus after it has been presented repeatedly. In simpler terms, it's the process wherein individuals become less interested or less responsive to an object or event they are exposed to over time. For example, if you've ever noticed that a clock's ticking becomes 'invisible' to your perception after a while, you've experienced habituation. This process is thought to be adaptive, as it allows organisms to focus on more important changes in their environment rather than wasting resources on the familiar and non-threatening.

In psychological studies, habituation can reveal a lot about an individual's cognitive processes. By measuring the decline in attention or reaction to a known stimulus, researchers can infer the subject's ability to learn and adapt. This is particularly useful when verbal communication is not possible, as in research involving infants or non-human animals.

Newborns cannot express what they perceive or pay attention to in the same ways adults can, making research in the early stages of life a unique challenge. To understand an infant's cognitive development, researchers often rely on indicators such as habituation. They present babies with a stimulus – a sound, image, or object – and observe how their responses change over time. A decreasing response suggests that the newborn is becoming habituated, indicating that they have noticed the stimulus enough times to find it less novel or interesting.

This kind of research has provided invaluable insights into the early stages of human development. It helps in assessing sensory and perceptual capacities of infants, as well as their memory. For instance, if a baby demonstrates habituation to a visual pattern, this suggests that they can recognize and remember the pattern, which is a sign of learning.

Perception and attention are closely intertwined with habituation. By definition, habituation affects how we perceive stimuli over time and where we direct our attention. Initially, when a new stimulus is perceived, it often garners significant attention. However, as one becomes more and more familiar with the stimulus, less attention is directed towards it, as per the principles of habituation.

Researchers quantify this shift to understand how attention works in humans and other animals. It can give us clues about what factors attract our attention and how we learn to ignore stimuli that we deem irrelevant or non-threatening. The principles of perception and attention are crucial for comprehending complex cognitive processes such as learning, memory, and consciousness. Habituation, therefore, is not just a simple decline in response; it's a window into the intricate workings of the mind.