Eye on Research: The Ethics of Research Using Animals

Research using animals has taught us many things about the development and biology of vision that have ultimately improved the lives of humans. However, there are obvious ethical implications regarding this. Let’s explore the research that has been conducted using animals, what we have learned from this research, as well as the ethics of this research.

David Hubel and Torsten Wiesel were awarded the 1981 Nobel Prize in Medicine for groundbreaking research on the visual system (Hubel & Wiesel, 1959, 1962, 1963, 1970; Wiesel & Hubel, 1963). Over more than two decades, they studied how neurons in the brain respond to visual input, primarily using cats and monkeys as research subjects.

They recorded the activity of single neurons by inserting tiny electrodes into specific regions of the visual cortex—a process known as single-unit recording. Through this work, they discovered that:

• Certain neurons respond specifically to lines and edges at particular orientations (a finding known as orientation selectivity).
• These neurons are organized into columns and hypercolumns within the visual cortex, forming a detailed map of how the brain processes visual information from the eyes.

Discovering the Critical Period for Vision

In one of their most influential experiments, Hubel and Wiesel sutured one eye of newborn kittens closed to study how visual experience affects brain development. They found that if kittens were deprived of input from one eye early in life, the neurons in the visual cortex that normally received input from that eye were taken over by neurons from the open eye.

This revealed the existence of a critical period—a window during early development when visual input is necessary for normal visual function to form. If sensory input is blocked during this period, neural connections can weaken or disappear permanently.

These discoveries helped scientists understand human visual disorders, such as amblyopia (lazy eye), leading to better early interventions for children at risk of vision loss.

Ethical Considerations

While this research was scientifically valuable, the methods—such as sewing a kitten’s eye closed—are deeply troubling to many people.

This raises difficult ethical questions:

• Is it ever acceptable to harm animals if the research may prevent blindness in children?
• Would your answer change if you were the parent of a child facing that outcome?
• How can researchers ensure compassion while pursuing scientific progress?

These are not simple questions, but they highlight the tension between scientific advancement and animal welfare.

In the U.S., any federally funded facility that conducts animal research must have an Institutional Animal Care and Use Committee (IACUC). Each IACUC includes scientists and administrators, a veterinarian, and at least one member of the public unaffiliated with the institution.