Free Psychology for Dummies by Adam Cash Page B

converts chemical energy into neural energy and sends that information to the area of the brain involved in analyzing taste information.

Finishing the Product: Perception
    Obviously, the world we’re in touch with through our senses is a lot more complex than just a bunch of singular sounds, smells, tastes, and other sensations. We hear symphonies, not just notes. We see fireworks, not just single photons of light. We indulge our taste buds with scrumptious meals, not just salty, sour, bitter, and sweet tastes. We can thank the ability of perception for all of these pleasures.
    Perception
is the process of organizing, analyzing, and providing meaning to the various sensations that we are bombarded with on a daily basis. If sensation provides us with the raw material, perception is the final product.
     

     
    There are two popular views of this complex process:
    Ecological view: This idea states that our environment provides us with all of the information that we need to sense the world; very little interpretation or construction is needed. For example, when I perceive a tree, it’s not because I’ve constructed a perception of it in my mind. I perceive the tree because the tree has provided me with all of the necessary information to perceive it as it is.
    Constructionist view: In this view, the process of perception relies on previous knowledge and information to construct reality from fragments of sensation. We are not just passive recipients of sensory information. We are actively constructing what we see, hear, taste, and so on.
    Regardless of whether you’re an ecologist or a constructionist, there are some basics to the process of perceiving. If sensation is the process of detecting specific types of energy in our environments, how do we know which information is worth detecting and which is just background noise? After all, we couldn’t possibly respond to every bit of sensory energy around us. We’d easily be overwhelmed with all the roaring traffic, howling wind, bustling pedestrians, and other stuff around us. The good news is that our perceptual systems have a built-in system for determining what information should be or is actually detectable.
    The concept of an
absolute threshold
refers to the minimum amount of energy in the environment that a sensory system can detect. Each sensory system has an absolute threshold below which energy does not warrant or garner perceptual attention.
    Another determinant of whether a stimulus is detected or not comes from
Weber’s law,
which gives the idea of the
just-noticeable difference (JND).
Each sensory system determines a constant fraction of intensity for each form of energy that represents the smallest detectable difference between energy intensities. The idea is that a stimulus has to exceed the JND in order for it to be detectable; otherwise, it will go unnoticed because the difference is too small.
    Yet, another theory known as
signal-detection theory
takes a slightly more complicated look at the problem. An overwhelming amount of the environmental energy around us is considered background noise. When we encounter a stimulus, called the
signal,
it’s analyzed based on our individual
sensitivity
and
response criterion.
Based on the sensitivity and response criterion of their individual sensory systems, people can either correctly detect a stimulus
(hit),
fail to detect a signal when there is one
(miss),
detect a signal when there isn’t one
(false alarm),
or report no signal when there isn’t one
(correct rejection).
    Our individual biases and motivations determine our response criterion and play a role in whether we make an accurate detection or not. So, when people think I’m not listening to them, it’s not my fault. I’m not detecting their signal because my response criterion is set not to respond to anyone talking to me at that moment. I’m an innocent victim of my perceptual processes.

Organizing by Principles
    The perceptual system is not made up