Certificate In Psychology (CPSY) Practice Exam

At what age does fetal response indicate an ability to detect light?

1. 15 weeks after conception

2. 5 weeks after conception

3. at birth

4. 26 weeks after conception

The correct answer is: 26 weeks after conception

Fetal response indicating the ability to detect light occurs at around 26 weeks after conception. At this stage of development, the retina in the fetus has formed sufficiently, enabling it to respond to light stimuli. Research utilizing ultrasound technology has demonstrated that at this gestational age, fetuses exhibit movements or responses when exposed to light, suggesting sensory capabilities have advanced to a point where light detection is possible. In early stages of pregnancy, such as 5 weeks or even 15 weeks after conception, the development of the visual system is still in foundational phases. During these earlier weeks, the structures that are essential for vision, including the retina and optic pathways, are not yet fully developed, which is why light detection capabilities are not present. Even at birth, while infants are exposed to light, their ability to perceive and process visual information is still immature compared to that of a fetus at 26 weeks. Therefore, the correct timeframe for the development of light detection abilities is indeed around 26 weeks after conception.