Do animals have feelings like we do?

What do we mean by feelings?

Here, a feeling means a subjective experience: something that is pleasant, unpleasant or otherwise has a quality for the creature. This differs from detecting a change and responding to it. A sensor can register heat without feeling hot. That comparison illustrates a distinction in meaning; it does not tell us which living things have experience.

It also differs from having a human-style account of yourself. A creature need not explain its mood in a sentence before an experience is possible. The Stanford Encyclopedia of Philosophy's discussion distinguishes subjective experience from several forms of self-awareness. It also explains why familiar human emotion words can be difficult to apply across species.

So the phrase like we do needs care. It could mean having any experience at all, having an unpleasant experience, or feeling exactly the same emotion in exactly the same way. These are different claims. Evidence supporting the first two does not give us access to every detail of another creature's inner life.

How can scientists investigate a creature that cannot tell us?

The challenge is to compare explanations of the observations. A movement away from a stimulus could be a simple protective response. A more informative study asks whether the animal remembers a relevant place, changes its preferences and responds differently when the unpleasant condition is relieved. Controls help test whether a simpler explanation fits.

Robyn Crook's octopus experiment combined these approaches. Animals avoided a chamber associated with an injurious stimulus. Local anesthetic treatment produced a preference for its associated chamber in affected animals, but not in controls without that condition. Nerve recordings also examined how information about the harmful stimulus reached the central nervous system.

The author interpreted the combined findings as evidence for an unpleasant, felt component of pain. The experiment did not record a feeling directly or show that octopus pain is identical to human pain. Its strength comes from several observations pointing toward the same interpretation. Its limits matter too: one experiment in one species cannot establish the full range of experience across all animals.

The 2024 declaration similarly distinguishes strong support in mammals and birds from a realistic possibility in a broader set of animals. Possibility and strong support are different levels of confidence. Neither phrase supplies a complete description of what an animal's world feels like.

Could an octopus have a very different kind of consciousness?

Yes, that is a serious possibility. The philosophical discussion of animal consciousness separates the distribution question, which creatures have experience, from the question of what their experiences are like. Answering the first does not automatically answer the second. A shared capacity for experience need not mean a shared way of experiencing.

Imagine trying to describe a new sense to someone who has never had it. You could explain what information it detects and how it guides decisions, while still struggling to convey how it feels. This imagined case helps clarify the difficulty; it is not evidence that octopuses possess any particular humanly unimaginable feeling.

We should therefore avoid two shortcuts. Familiar-looking behavior does not guarantee a familiar feeling. Unfamiliar behavior does not establish an absence of feeling. A useful description names the observed capacity and states separately what researchers infer about experience. It leaves the exact character of that experience open where the evidence cannot reach it.

What do plant signals actually show?

A 2018 experiment by Masatsugu Toyota and colleagues traced a defense-signaling process in plants. Damage released glutamate, which activated channels involved in a calcium signal traveling to distant organs. The work helps explain how an injury in one area can trigger responses elsewhere in the plant.

This is impressive coordination. It establishes neither an unpleasant experience nor a plant equivalent of a human emotion. The measurement concerned molecules, signals and defense responses. The extra claim that those processes feel like something would require an additional argument and evidence connecting the measured process with experience.

A review by Jon Mallatt and colleagues argues that plant signaling and proposed learning effects do not provide adequate evidence of consciousness. That is an assessment of existing arguments and observations. It does not turn every conceivable account of consciousness into a settled question. The careful conclusion is that responsiveness alone is insufficient evidence for plant experience.

Would evidence that plants learn settle the question?

No. First the claimed learning needs to be reliable; then its relationship to experience needs a separate assessment. In a 2016 study, Monica Gagliano and colleagues paired airflow with the location of light as pea seedlings grew through a branching apparatus. They reported that later growth direction reflected the pairing and interpreted the result as associative learning.

Kasey Markel subsequently failed to reproduce the effect. The original authors' published comment argued that the replication's less consistent response to light made its setup unsuitable. In his reply, Markel acknowledged the reduced ability to detect an effect but disputed their proposed explanation. He did not claim to rule out plant learning altogether.

That exchange leaves this particular result contested. It is a reason to seek a reliable experiment, rather than a reason to announce either plant consciousness or the impossibility of plant learning. Even a replicated association between two cues would establish a capacity to learn under those conditions. Whether that capacity entails a felt experience is another question.

What is the strongest objection, and how can you check a claim?

The strongest objection is that our tests may favor minds resembling our own. An unfamiliar system might have experience that our present measurements miss. This is a legitimate challenge to the reach of an inference. It is not positive evidence that a particular untested organism has experience. A better test would need to explain what observation should differ between competing accounts.

Check a headline by opening the study and writing two separate sentences: what was measured, and what the authors inferred. Then look for controls and independent attempts to repeat the result. A video of a plant moving answers a different question from an experiment designed to investigate learning, and neither automatically answers the question of subjective experience.

Do this by reading existing research, rather than by causing an animal distress yourself. For the broader philosophical question, see the relationship between mind and brain. You can take animal experience seriously while keeping your confidence tied to the evidence for the particular creature and capacity being discussed.