Explain how genes affect behavior using the example of fragile X syndrome.

What will be an ideal response?

The ideal answer should include:
1. Genetic level: Fragile X occurs when a gene on the X chromosome is silenced due to a mutation. The gene thus fails to instruct the cell to assemble a particular protein known as FMRP that is used in building the brain.
2. Neural level: A brain deficiency of FMRP leads to reduced neural activity and widespread low-level impairment of brain areas involved in executive functions and other cognitive processes.
3. Cognitive level: Executive functioning, memory, speech, language, and spatial dysfunctions occur, leading to poorer performance on tests of these abilities.
4. Environmental level: The cognitive impairments affect the way the individual selects and responds to environmental stimuli.
5. Behavioral level: The individual has problems such as hyperarousal, lack of inhibitions of behavior, and social anxiety.