Public Opinion and Animal Sentience

Public opposition to the use of animals in experiments has increased steadily, reaching 52% of the population in 2018.¹ A 2024 survey published by the Animal-Human Policy Center at Colorado State University found that approximately 61% of respondents were “very or extremely concerned” about animals used in experimentation and only 22.5% of respondents “somewhat or strongly agreed” that laws in the U.S. aimed at protecting the welfare of animals used in experimentation were “strong.”² Another 2024 survey by Morning Consult found that 80% of respondents agreed or strongly agreed with the statement: “The US government should commit to a plan to phase out experiments on animals.” Similar responses were elicited with approximately 85% agreement to both the following statements: “Government funding should prioritize research methods that do not involve animal testing,” and “Animal experimentation should be phased out in favor of more modern research methods.”³ In 2025, Gallup reported that 53% of Americans felt that medical testing on animals was morally unacceptable, up from 35% in 2001.⁴

The public is even less approving of animal use when experiments are invasive or viewed as less beneficial or necessary for human health—as in the case of cosmetics testing—or when non-animal methods exist.

Research has revealed that universities and media outlets often exaggerate findings from experiments on animals and “promote research that has uncertain relevance to human health and do not provide key facts or acknowledge important limitations.” A study examining media coverage of animal-based preclinical research found that the reports were inflated and often prematurely implied imminent “breakthroughs” relevant to human medicine. “Of 27 unique published ‘breakthroughs’, only one had clearly resulted in human benefit. Twenty were classified as failures, three were inconclusive and three were partially successful.”⁵ A 2021 study found that 69.5% of news articles about Alzheimer’s disease research papers omitted any mentions of mice in their headlines and overstated the findings.⁶ The use of misleading language in news reporting is not limited to Alzheimer’s disease and has also been observed in coverage of other diseases, including cystic fibrosis⁷ and multiple sclerosis.⁸ Because experimenters rarely publish the results of failed animal studies, other scientists and the public lack access to information about the ineffectiveness of animal experimentation. If the public were fully aware of the extensive evidence that animal use may be hindering the development of effective treatments, opposition to such experiments would likely grow substantially.

The minority of the public that continues to support experiments on animals usually predicates its support on the mistaken belief that oversight bodies would only allow these experiments if they were essential to developing treatments for human disease and if the harm to animals were outweighed by the benefits to humans. Clinician-scientists in Turkey “found that more than 40% of papers based on animal models that were presented at the national orthopaedic congress of their country (population 83 million) over a 9-year span were never published, and of those that were, nearly 40% were never cited or were cited only once. All of this nonimpact cost more than 9400 animals their lives.”⁹¹⁰ In 2020, researchers who evaluated studies “published in the two clinical journals with the highest Impact Factor in each of 10 surgical specialties found the median number of citations of animal research papers by subsequent human/clinical research over a 10-year span was only one (with the high end of the range being five), suggesting minimal translation of animal studies to research in humans.”¹¹¹²

Recognition of animal sentience has also played a role in the public’s growing opposition to experiments on animals. This is particularly true for the species with whom humans share their homes (e.g., dogs and cats) and those perceived as having higher cognitive abilities (e.g., primates). However, public concern for other species has also increased. Philosophers and bioethicists have emphasized that modern views on animal welfare prioritize sentience as a central component of ethical considerations in animal experimentation.¹³

The current state of research on cephalopod, decapod, and insect sentience^14151617 has prompted many countries, including those in the EU as well as Australia, Canada, Norway, Switzerland, and the U.K., to update their animal welfare laws. NIH has solicited feedback from scientists and the public to establish guidelines for the use of cephalopods in experiments,¹⁸ noting that “[a] growing body of evidence demonstrates that cephalopods possess many of the requisite biological mechanisms for the perception of pain.”¹⁹

Recent studies reveal that many animals—in addition to feeling physical and psychological pain and distress—show empathy, self-awareness, and language-like abilities. They also exhibit tool-related intelligence, engage in pleasure-seeking behavior, and have advanced problem-solving skills.²⁰²¹ These realities have prompted academics, intellectuals, philosophers, and ethicists to seek the consideration of animal sentience and consciousness in decision-making about how animals are treated in science and other areas. For example:

• The 2024 New York Declaration on Animal Consciousness, citing empirical evidence of “a realistic possibility of conscious experience in all vertebrates (including reptiles, amphibians, and fishes) and many invertebrates (including, at minimum, cephalopod mollusks, decapod crustaceans, and insects),”²² called for the consideration of the realistic possibility of conscious experience in other animals as part of the animal welfare decision-making process.
• In 2015, more than 150 academics, intellectuals, and writers backed a report by the Oxford Centre for Animal Ethics that condemned experiments on animals as both morally and scientifically indefensible. “The deliberate and routine abuse of innocent, sentient animals involving harm, pain, suffering, stressful confinement, manipulation, trade, and death should be unthinkable. Yet animal experimentation is just that: the ‘normalisation of the unthinkable,’”²³ write the report’s authors. They conclude that experimenting on animals contradicts what we now know about animals’ ability to experience not only pain but also shock, fear, foreboding, trauma, anxiety, stress, distress, anticipation, and terror.
• In 2012, a prominent international group of neuroscientists issued The Cambridge Declaration on Consciousness, which definitively stated that “humans are not unique in possessing the neurological substrates that generate consciousness” and that, like humans, “[n]on-human animals have … the capacity to exhibit intentional behaviors.”²⁴

The statistics on failed translation make it clear that animals are not appropriate human surrogates in biomedical research, but when it comes to their capacity to suffer, how much like humans do they need to be before a critical review of animal-based research is considered mandatory?