Information enters the brain through encoding, which is the input of information into the memory system. Once sensory information is received from the environment, the brain labels or codes it. The information is then organized with similar information and connected to existing concepts. Encoding occurs through automatic processing and effortful processing.

Automatic processing involves the encoding of details like time, space, frequency, and the meaning of words, usually done without conscious awareness. Examples of automatic processing include recalling what you ate for lunch or the last time you studied for a test.

In contrast, effortful processing requires work and attention to encode information. Studying for a test, for instance, involves this type of processing as it demands focus and active engagement to encode the material.

Processing can then be subdivided into three types of encoding: semantic, visual, and acoustic. Semantic encoding is the encoding of words and their meanings. William Bousfield (1935) demonstrated this through an experiment where participants were asked to memorize 60 words divided into four categories of meaning. Although the words were presented randomly, participants tended to recall them in categories, showing attention to their meanings during learning.

Visual encoding involves the encoding of images. To illustrate, consider the following list of words: car, level, dog, truth, book, value. Words like car, dog, and book are easier to recall because they evoke images of objects. In contrast, words like level, truth, and value are more abstract and harder to remember.

Acoustic encoding is the encoding of sounds, particularly words. An example of this is hearing a song on the radio that you have not heard in ten years, yet recalling every word. The sounds of the words are encoded, which is why much of what is taught to young children is done through song, rhyme, and rhythm.