The opponent-process theory of color vision posits that colors are processed in pairs of chromatic opposites. This theory explains why the suffusion of reddish hues from the direct sunlight though Lucia’s eyelids left an afterimage of bluish color in their absence. The trichromatic theory of color vision attributes the discernment of color to specializations of the eye’s cones and does not account for negative afterimages. Gestalt theory concerns the perception of parts and wholes. Inattentional blindness is not a theory, but a phenomenon in which objects that are plainly available in an individual’s perceptual field nonetheless go unnoticed due to a lack of attention paid to them.

The situation with Angela is the best example of synesthesia—a phenomenon, in which stimulation of one sensory pathway triggers a response by a different, unrelated sensory pathway. People with synesthesia might see a certain color whenever they taste a certain food. The important thing to note is that in synesthetic perception, the person experiences the synesthetic connection as being projected outside the body, not just in the mind’s eye (e.g. Angela does not simply imagine the color red when she sees the letter A: she actually sees A as being colored red, even if it is printed in plain black font). The other situations described in the answer choices reflect other psychological phenomena. Ashley is experiencing amnesia; George, phantom limb syndrome; and Taylor, taste aversion.

The Gestalt laws of perception are a set of principles that govern the way humans tend to perceive visual stimuli as a collective whole, rather than discrete individual objects or events. Different names are given to the specific applications of this overarching principle. For example, the phi phenomenon refers to the tendency to perceive a series of lights blinking on and off down a line as a single light moving along, instead of a number of lights turning on and off for no apparent reason. The law of prägnanz (not the prägnanz effect that was listed as an answer choice) is the Gestalt law that suggests that people perceive visual stimuli in terms of the simplest explanation or form possible. Opponent-process theory is a concept of visual perception that explains why some colors seem to be incompatible (e.g. we might see a yellowish green, but we cannot really imagine a reddish green). 

The answer is "the least amount of information that's necessary to understand a stimulus is actually present." The average amount of information that's necessary to understand a stimulus is actually present holds no relevance in psychological terms, while the amount of stimulus that's necessary to determine if a stimulus has been changed is called the difference threshold. The other answers hold no actual meaning in psychological terms, such as the max amount of stimulus, or the difference in stimulus to determine if the stimulus has been kept the same. 

Mania and anxiety are most closely associate with behavior and not sensory perception. The main difference between delusions and hallucinations are that delusions are false beliefs. Conversely, "hallucinations" are false perceptions from a stimulus that does not exists. These perceptions are generated by the mind and occur during consciousness. 

Absolute threshold is the lowest level of stimulation that an organism can detect. For example, the quietest sound that a human can hear is their absolute threshold for hearing.

Top-down processing involves the impact of prior knowledge on sensation and perception. Many optical illusions are successful by capitalizing on our prior knowledge to influence our perception of an image.

Selective attention allows one to focus on certain specific sensory information, while ignoring other sensory input. All of the given examples would require selective attention, and in fact, almost every situation you could imagine would require some level of selective attention. For example, when reading a book, even if you are in a quiet room, you require selective attention to focus on the pages and words while ignoring any sort of background noise or action in your periphery. 

The cocktail party effect explains one's ability to focus one's attention on one particular sound (an auditory stimulus) while simultaneously filtering out others. The name for this effect comes from the ability of a person at a party to focus his attention onto a particular conversation, while drowning out the other conversations happening at the party.

The cocktail party effect describes a person's ability to attend to just one voice among a group of voices--akin to a party guest's ability to listen to just one person's voice among the voices of many conversations.