Yet hidden inside are microphones, motion and conductivity sensors, and wireless connectors that turn this $10 everyday object into what its makers bill as the "world's first smart hairbrush", costing close to $200. Artificial intelligence has made it to the boudoir. The data gathered by the brush are sent to an app, where software algorithms produce a score for hair quality and recommend techniques - and L'Oréal products - that might improve it. The brush even vibrates a little if you brush too fast and damage your hair. "I was stunned by what you can infer and interpret by the noise of the friction of the hair brush," says Cedric Hutchings, chief executive of Withings, the Nokia-owned company that developed the Kérastase Hair Coach with L'Oréal, the French cosmetics company.
Yet Mr Hutchings admits that the product, unveiled at the Las Vegas tech show before it goes on sale this year, has been met with scepticism. "Eyebrows were raised," he says. "People said: 'Seriously, a smart brush?'" If that was attendees' reaction early in the week, by the end of CES this weekend they should be all too familiar with the concept. The "internet of things" has been surpassed by AI as the most ubiquitous buzzword at CES, as start-ups and tech giants alike attach it to everything from cars and fridges to toothbrushes and shoes. "In 2015, we were focused primarily on connecting devices," says BK Yoon, chief executive of Samsung Electronics' home appliances unit. "Now we have moved beyond simple connection." The AI wave that is poised to sweep across consumer technology comes in two forms. The first involves using voice as a new - and simpler - way to interact with everyday gadgets. Alexa, Amazon's virtual assistant, which is activated by simply calling out its name and making a request, has been particularly popular among device makers wanting to add smart functionality to their products.
Alexa, which Amazon lets other manufacturers use free of charge, will soon be accessible from millions of Ford cars' dashboards, Whirlpool washing machines, LG fridges, Westinghouse TVs and Lenovo soundboxes.As well as controlling the devices in which it is encased, Alexa can switch on lights and open doors, not to mention read the news, book a cab on Uber or order a pizza. Eventually, Amazon hopes to make it a true intelligent agent, able to understand and anticipate users' wants and needs at a much deeper level.Device makers are hopeful that embedding this kind of intelligence in their hardware can make consumers understand the value of the internet of things - the tech world's dream of connecting billions of inanimate objects to the internet and making them smart. Long hyped, the connected home thermostats and "wearable" devices it has produced have not resonated much with those outside the tech bubble.
But just as the Windows operating system dominates PCs and Google's Android has a significant share of the smartphone market, new digital assistants like Alexa could give their creators inordinate power. Jen-Hsun Huang, chief executive of US chipmaker Nvidia, expects consumers to coalesce around a handful of virtual assistants from the likes of Google, Amazon or Microsoft as they become more accustomed to the technology.
"When you are using Google Assistant, you get used to the capability of that assistant," he says. "Over time it's easy for people to use that capability rather than working across four or five different assistants." Electronic hardware makers are trying to hedge their bets. Samsung recently bought an AI start-up whose founders also created Apple's Siri, potentially giving it a rival platform and saving it from the kind of dependence it has had on Google's Android operating system for its smartphones.
Don Butler, head of Ford's connected car initiative, is also wary of becoming dependent on Apple and Google, which have their own designs on the auto industry. That has made Amazon a natural ally, he says, though Ford also expects eventually to open up to other digital assistants. The second aspect of the coming AI revolution involves analysing data collected by smart devices to make them more useful. Until now, many products have gathered knowledge without using it. The big development in AI research has been "deep learning", which can make sense of this real-world data.
"AI is a dream that everybody has had about the potential of computers for a very long time," says Mr Huang, whose graphical processing unit chips are used in many internet companies' data centres. "Because of deep learning and [graphical processing chips] making deep learning practical, we are really seeing a new tool that has reignited the AI revolution." Tech companies such as Google, Facebook and Amazon hold troves of data, using them to train their systems to do things like understand language or recognise human faces in a crowd.
But Mr Huang predicts that start-ups focusing on much narrower problems will be able to make gains with far smaller data sets, gleaning meaningful insights from low-cost sensors such as those found in the smart hairbrush. "This is a great time for start-ups," he says. "It's not true all these cloud services have all the data in the world . . . We all have our own data. Because of AI these micro businesses are going to surge." Some of the items from which data are being gathered can sound unlikely. French company Kolibree, for instance, has been collecting information for three years using its smart toothbrush - a gadget that measures things like how long people brush their teeth. Its latest model, unveiled at CES , goes a step further and tries to assess which of 16 locations in the mouth the brush is in at any particular time. To do that, says chief executive officer Thomas Serval, it analyses data from "tens of thousands of brushes" to train the technology. Giving people feedback about how well they are brushing should improve dental hygiene, he says. The incipient intelligence on display this week in smart fridges, toothbrushes and hairbrushes prompts inevitable suspicion: does the world need such digital wizardry? As so often when the tech world races to invent the future, there is a sense that technology is being applied for its own sake.
"The real difficulty in this process of fully realising [the internet of things] has been identifying . . . what is really useful to consumers," says Mr Yoon, "and how to make consumers notice and really feel the difference." As Brian Blau, an analyst at tech research group Gartner, put it after viewing the goods at CES: "You can control your blinds, you can control your appliances, you will be able to talk to the digital assistant in your refrigerator. But are any of those things interesting?"
Part of the problem is that some capabilities of this technology have raced ahead of others, challenging gadget-makers' ability to employ AI systems effectively. UBTech, a maker of small humanoid robots designed as domestic companions, has put facial recognition software in its machines so they can assess how their human owners are feeling. But the capability does not yet exist to use that knowledge to adjust a robot's voice tone or subtly change other behaviour, says John Rhee, general manager for North America at UBTech. Instead, the company's Lynx robot does its best to express itself: it flashes LED lights and rotates and nods its head. The race to plant intelligence widely has pushed into some unlikely places. Shadecraft, a start-up in Los Angeles, this week showed off its prototype of a smart garden umbrella. The device, expected to be priced at $2,500-3,000, will rotate with the sun - and like all the best smart gadgets, it will come with a built-in intelligent agent.
Armen Gharabegian, Shadecraft's chief executive, brushes off questions about why robotic intelligence is needed for a device like this. Over time, he says, as prices fall and consumers' expectations of everyday digital objects change, it will be second nature to expect an umbrella to move itself. "Ten years from now, it's going to be kind of awkward sitting on a beach not having an umbrella move to the sun, and for you to ask the robotic shade to order you a drink," he says. "Right now, we're living in the dark ages."