AP Psychology › Unit 1
Every thought and behavior has a biological basis. Unit 1 covers heredity and environment, the nervous system, how neurons fire and communicate, the brain, sleep, and sensation. The exam stresses functions over naming parts. You might apply knowledge of a neurotransmitter or brain region to a scenario, or identify the research design in a study. Students often confuse agonists, which mimic or boost a neurotransmitter, with antagonists, which block it. Another common mix-up is reversing the jobs of the sympathetic and parasympathetic nervous systems.
These are taken from the Regular set, with the answer and explanation shown.
1. A compressed nerve in Maria’s lower back sends tingling and weakness down her leg. The nerve runs from her spinal cord to the muscles and skin of her leg. Which part of the nervous system is affected?
Answer: A. The peripheral nervous system relays messages between the central nervous system and the rest of the body. A nerve that carries touch from the skin and movement commands to leg muscles belongs to its somatic division.
Common trap: Choosing the central nervous system because the nerve starts at the spinal cord. Only the brain and spinal cord themselves are central. Nerves that branch out from them are peripheral.
A patient’s corpus callosum was cut to treat severe epilepsy. She stares at a dot in the center of a screen. A picture of an object is flashed for a fraction of a second to one side of the dot. She then says what she saw. Next, she reaches behind a barrier with one hand and tries to find the object by touch.
| Picture flashed to | Names the object? | Left hand finds it? | Right hand finds it? |
|---|---|---|---|
| Right visual field | Yes | Rarely | Yes |
| Left visual field | No ("I saw nothing") | Yes | Rarely |
2. Based on the table, which hemisphere produces this patient’s speech, and what is the evidence?
Answer: D. Pictures in the right visual field go to the left hemisphere. She names those pictures but not left-field ones. So the hemisphere that speaks is the one that receives right-field input: the left hemisphere.
Common trap: Choosing an answer about the hands. Hand results show which hemisphere saw the picture, but naming is the evidence about speech. Also remember the crossover: right field means left hemisphere.
3. In a dark movie theater, Ben cannot tell what color the seats are, but he spots movement best out of the corner of his eye. Which explanation accounts for both observations?
Answer: D. Rods are photoreceptors that work best in low light and detect shapes and movement, not color. They are concentrated in the edges (periphery) of the retina. In the dark theater, Ben relies on rods, so colors fade and side vision is sharpest.
Common trap: Choosing an option with cones. Cones handle color and detail, but they need brighter light. In the dark, rods take over.