Ch. 5 Paragraphs

1. What are hits and false alarms, and how are they used in signal detection theory to separate the experiment participants sensitivity to a signal from the response bias of that participant?
      A hit is when a participant reports a signal when a stimulus signal has been given. A false alarm is when a signal has been reported but no stimulus signal was activated. Response bias refers to a participant's tendency to report detecting the signal in and ambiguous trial. When a participant is given any previous knowledge about something before being tested. they might be partial to either report a signal regardless of whether or not they actually detected the stimulus and vice versa.
2. Where is light transformed into neural signals, and how do these neural signals reach the primary visual cortex?
      After light passes through the cornea and the lens, it is refracted to the retina at the back of the eyeball. Then photoreceptors in the retina transduces the light in the rods and cones. After the information has been transduced, it is passed through bipolar amacrine, and horizontal cells that perform sophisticated computations on the incoming signals. Lastly the signal converges on ganglion cells, in the optic nerve and send the translated signal through neurons up to the thalamus.
3. What evidence indicates that our ability to see colors is based upon three underlying components?
       Because there are three different types of cones, S, M, and L that can perceive different wavelengths of colors, is one reason why we can see colors. The visible spectrum resides in waves that length from 400-700 nanometers, darker cooler colors being near 400 and lighter warmer colors measuring near 700 nm. In the color spectrum there are also three primary colors, red blue, and yellow, as well as three dimensions, hue, lightness, and saturation.
4. What evidence indicates that our ability to perceive the identity of an object is somewhat separate from our perception of its location? What areas of the brain are involved in the perceptions?
       Using equipment such as the fMRI, scientist have found that neural activity is prominent in different parts of the brain for the identification of an object, as opposed to its location. Neural impulses received by the occipital lobe from the eyes are divided into two streams. The ventral "what" stream goes to the temporal lobe in order for the item to be identified. The dorsal "where" stream goes to the parietal lobe in order to be translated as information concerning the location of an object.  
5. How are we able to perceive objects, or even pictures, as three-dimensional, that is, as having depth?
A three-dimensional array of objects creates exactly the same image on the retina that a photograph does. We are able to perceive depth in these two-dimensional patterns because the brain applies the same rules or mechanisms that it uses to wok out the spatial relations between objects in the three-dimensional world. Binocular depth cues are cues received from both eyes that have to do with binocular disparity or the difference between the perceptions of the two eyes to determine the spatial distance in the real world. Monocular depth cues are those received from each individual eye which are better for determining pictorial depth.