A handle made of polished stainless steel and a handle made of oiled oak can have exactly the same room temperature – yet one feels cold and the other feels warm. If you wonder why wood feels warm even though a thermometer shows the same value for both materials, you quickly arrive at a physical effect that influences much more than just the feeling in your hand: Researchers have measured that the choice of material can affect pulse, blood pressure, mood, and even judgments about other people.
Why wood feels warm even though both materials have the same temperature
The explanation initially has nothing to do with psychology, but with pure physics. Every material conducts heat at different speeds. When you touch metal, it draws heat from the skin much faster than the body can replenish it – the skin at the point of contact cools down noticeably, and thermoreceptors signal "cold." Wood conducts heat much more slowly: it hardly extracts any energy from the skin, so the point of contact hardly cools down, and the material feels warm, even though both objects had been in the same room for exactly the same amount of time beforehand.
The decisive factor here is the so-called thermal conductivity of a material, combined with its thermal effusivity, which describes how quickly a common temperature is reached at the contact surface of two bodies. Metals have very high thermal conductivity and effusivity, while wood has very low. This is precisely why tiles feel colder than textile mats in the same bathroom, and exactly why metal door handles feel more unpleasant than handles made of wood or plastic in the cold season – not because they are colder, but because they transport heat away faster.
For the design of objects handled daily, this is more than just a physical footnote: one and the same shape can be perceived as inviting or chilly, depending on the material – without any change in the actual temperature in the room.
The body reacts measurably to materials
That this effect goes beyond a mere gut feeling is shown by a 2017 Japanese study by Harumi Ikei, Chorong Song, and Yoshifumi Miyazaki, published in the International Journal of Environmental Research and Public Health. The researchers had 18 female students touch white oak, marble, tile, and stainless steel with their palms for 90 seconds each, while measuring blood flow in the prefrontal cortex and heart rate variability as an indicator of autonomic nervous system activity.
The result: when touching oak, the oxygen saturation in the prefrontal cortex dropped much more sharply than with marble, tile, or stainless steel – a pattern usually associated with mental relaxation. At the same time, a marker for parasympathetic (i.e., calming) nervous system activity increased significantly more after contact with wood than with marble or stainless steel. In accompanying mood questionnaires, participants reported significantly lower levels of tension and overall mood disturbance after contact with wood compared to the other three materials, and they subjectively described oak as significantly more pleasant, relaxing, natural, and warmer than the comparison materials.
The study is small – 18 participants, exclusively women of student age – and therefore cannot be applied to all people without verification. Within this sample, however, the difference between wood and the smooth, hard materials was consistent and statistically clear.
How much wood a room can handle
An older, frequently cited paper by the same research group led by Yuko Tsunetsugu in 2007 examined entire rooms rather than individual material samples. In full-scale model rooms, the proportion of wood on walls, ceilings, and floors was set to 0, 45, and 90 percent while the pulse rate, blood pressure, and brain activity of the test subjects were recorded.
- 0 percent wood: Diastolic blood pressure dropped noticeably, and changes in the autonomic nervous system remained small overall.
- 45 percent wood: Diastolic blood pressure also dropped significantly, the pulse rate rose slightly – this room was subjectively rated as the "most pleasant" by the participants.
- 90 percent wood: Systolic and diastolic blood pressure dropped sharply at the beginning, brain activity declined rapidly, and pulse rate increased.
The honest reading of these figures is not that "a lot of wood is always better," but that different proportions of wood trigger different – sometimes opposing – physiological reactions. In this study, the middle proportion of 45 percent was felt to be the most comfortably balanced, not the extreme. For interior design, this means that material in moderation often works more reliably than material in excess.
Warmth in the hand, warmth in judgment
A widely cited experiment by psychologists Lawrence E. Williams and John A. Bargh, published in the journal Science in 2008, went even further. In a first trial, 41 students held either a cup of hot or iced coffee for a few moments before having to assess a fictional person based on a short text. Those who had previously held the hot cup rated the described person on average as "warmer" in an interpersonal sense – i.e., more generous and caring – than the group with the cold cup, while neutral traits like "honest" remained unaffected by the temperature.
In a second trial, 53 participants held a warm or cold thermal pad, supposedly for testing purposes, and were subsequently allowed to choose between a drink for themselves or a small gift for an accompanying person. After holding the cold pad, participants chose the gift for themselves much more frequently; after the warm pad, they chose the gift for the other person more frequently. None of the participants reported having noticed any connection between the temperature of the object and their own decision afterwards.
The authors interpreted the result as evidence that early childhood bodily experiences – such as being cuddled by a warm person as a baby – remain closely linked to the abstract concept of "warmth" in an interpersonal sense in adulthood, so that a purely physical temperature experience can unconsciously impact social judgments and even behavior.
What remains of this effect – and what does not
As memorable as the experiment is, the body of studies regarding it is significantly more mixed today than the original publication suggested, and that is part of an honest assessment. In 2014, a team led by Dermot Lynott attempted to repeat both Williams and Bargh's experiments in the journal Social Psychology with significantly larger samples – 128 and 177 participants respectively, instead of the original 41 and 53. In both cases, practically no effects were found (correlations near zero), and an accompanying Bayesian analysis spoke clearly for the assumption that there is no connection between physical and social warmth – not just that the original effect failed to appear this time.
This pattern – a sensational individual finding that weakens or disappears in larger-scale repetitions – affects an entire branch of research known as "embodied cognition" and is part of the broader replication debate in social psychology over the past decade and a half. This does not mean that bodily sensations have no influence on our experience – the physiological reactions to materials described above are independently well-documented. However, it does mean that the punchy phrase "a warm coffee cup makes people more generous" should now be read with significantly more caution than the reporting after 2008 suggested.
Why material still counts in the design of everyday objects
Even without the punchy coffee-cup effect, enough remains to take material choice in the design of everyday objects seriously: the physiologically well-documented reactions to wood compared to smooth, hard surfaces, and the equally well-documented physics behind why materials feel different at the same temperature. In design history, this can be traced in many examples: Scandinavian post-war designs deliberately used light, oiled wood instead of the cool chrome and glass of the preceding modernism, and companies like Braun under Dieter Rams in the 1950s and 1960s shaped a design language that gave technical devices warm, matte surfaces and rounded edges instead of making them appear clinically smooth.
The difference becomes particularly clear with objects traditionally read as medical or requiring care: a shiny stainless steel container is quickly reminiscent of an instrument tray, both visually and haptically, while a case made of a matte, warm material is more reminiscent of a piece of jewelry or stationery. This difference is not only aesthetic, but – as the studies described above show – also physiologically perceptible, long before a person consciously thinks about "design."
When the sense of touch fades, material counts even more
Another often overlooked aspect concerns the sense of touch itself. A 2024 study by Léonard Samain-Aupic and colleagues from Aix-Marseille University, published in Frontiers in Aging Neuroscience, examined the tactile sensitivity of 96 healthy women between the ages of 20 and 75 on the fingertip, forearm, and cheek. Among other things, they measured the minimum force a fine probe had to apply for the touch to be perceived at all.
The result was more nuanced than one might initially expect: at the fingertip, the perception threshold increased significantly with age – for the ten youngest participants, it averaged around 2.4 millinewtons, while for the ten oldest it was around 5.8 millinewtons, more than twice as high. On the forearm and cheek, however, there was no significant correlation with age. The age-typical decline in tactile sensitivity thus primarily affects the fingertips – exactly the part of the body with which most people grasp, feel, and operate objects in everyday life.
For objects that must be gripped regularly with the fingertips, this means: the less finely the fingertips can detect fine structural differences, the more weight other, more robust signals gain – perceptible edges, a clearly defined resistance when gripping, a pleasant rather than unpleasantly cool surface. What is a pleasant detail for younger hands can become a criterion with declining fingertip sensitivity that determines whether an object is picked up gladly or not at all.
Common misconceptions
Two common simplifications can be corrected from the various studies. First: "More wood is always better" – the Tsunetsugu experiment shows that a solid-wood room (90 percent) triggers different, sometimes stronger physiological reactions than a moderate proportion, and that the subjectively most comfortable variant in this study was not the most extreme. Second: "A warm object in the hand automatically makes you more likable" – this punchy interpretation of the coffee-cup experiment is no longer considered tenable after the large-scale replication studies of 2014, even if the physiological reactions to materials themselves have been well replicated and are consistent across several studies.
Frequently asked questions
Does a warm object automatically make a person more likable?
The original experiment by Williams and Bargh from 2008 suggested this, but it could not be confirmed in two large-scale replication studies from 2014 with significantly larger samples. The measured effects were practically zero. Today, the effect is no longer considered a proven finding.
Why does metal feel colder than wood, even though both have room temperature?
Because metal transports heat away from the skin much faster than wood. The skin cools down noticeably at the point of contact and signals "cold," even though the thermometer shows the same value for both materials. The decisive factors are the thermal conductivity and the thermal effusivity of the respective material.
How much wood should an interior contain to have a beneficial effect?
In the Japanese model room study from 2007, a wood proportion of 45 percent on walls, ceilings, and floors was subjectively rated as most pleasant, while 0 and 90 percent each showed different physiological patterns. The study does not allow for a blanket percentage for every room, but it suggests that a moderate proportion often works more reliably than an extreme one.
Does the sense of touch really decline with age – and everywhere equally?
A 2024 study of 96 women between 20 and 75 found a significant age-related decline in tactile sensitivity at the fingertip, but not on the forearm or cheek. The effect thus apparently affects certain skin regions more strongly than others.
Does the physiological effect of wood only apply in comparison to metal?
No. The 2017 study by Ikei, Song, and Miyazaki compared oak with three different materials – marble, tile, and stainless steel – and measured weaker calming effects for all three comparison materials than for wood.
Is the research on "embodied cognition" refuted overall?
No, not across the board. Individual, particularly punchy findings like the coffee-cup effect have not been confirmed in replication studies, while other relationships – such as physiological reactions to different materials – have been consistently reproduced in several independent studies. Blanket statements in either direction do not do justice to the inconsistent body of evidence.
At Oxionix, we see this as the task of good design: to choose and shape everyday objects so that they feel familiar and warm instead of cool and clinical.
Sources
- Williams, L. E., & Bargh, J. A. (2008). Experiencing Physical Warmth Promotes Interpersonal Warmth. Science, 322(5901), 606–607.
- Lynott, D., Corker, K. S., Wortman, J., Connell, L., Donnellan, M. B., Lucas, R. E., & O'Brien, K. (2014). No Evidence That Experiencing Physical Warmth Promotes Interpersonal Warmth: Two Failures to Replicate Williams and Bargh (2008). Social Psychology, 45(3), 216–222.
- Ikei, H., Song, C., & Miyazaki, Y. (2017). Physiological Effects of Touching Wood. International Journal of Environmental Research and Public Health, 14(7), 801.
- Tsunetsugu, Y., Miyazaki, Y., & Sato, H. (2007). Physiological Effects in Humans Induced by the Visual Stimulation of Room Interiors with Different Wood Quantities. Journal of Wood Science, 53, 11–16.
- Samain-Aupic, L., Dione, M., Ribot-Ciscar, E., Ackerley, R., & Aimonetti, J.-M. (2024). Relations Between Tactile Sensitivity of the Finger, Arm, and Cheek Skin over the Lifespan. Frontiers in Aging Neuroscience, 16, 1387136.
- Thermtest: Touch Metal, Touch Wood – Thermal Conductivity Experiment.
