Imagine if every time you went to the supermarket, your shopping cart came loaded with the same box of cereal.

This cereal happens to be the most popular, so it’s convenient for the store to have it in the cart. If you don’t like it, it’s simple enough to put it back on the shelf and grab a different box.

That’s essentially the crux of Google’s defense against the Justice Department in a consequential antitrust trial — the federal government’s first such case in the modern internet era — that is now unfolding in court.

The government has accused Google of illegally using partnerships with handset makers, computer manufacturers and browser developers to stifle competitors in online search. Under those partnerships, the Justice Department argues, Google made its search engine the default service on an overwhelming majority of consumer electronics, like smartphones. That then deterred people from trying alternative search engines, like Bing, DuckDuckGo and others.

But Google has argued that it’s easy for people to change their search engine — just as simple as putting a box of cereal back on the store shelf.

The trial raises questions about how and why we use Google search. Many of us grew up doing web searches on Google because it seemed to deliver the best results with minimal effort. But if something better came along, would we really have known since Google came loaded on most of our devices? And even if we had known, would we have just stuck with Google since its search engine was set as the default?

I decided to test how easy or hard it really is to switch to a different search engine. In a blog post this month, Google said the change was a straightforward process and offered three examples:

• On an iPhone, it takes four taps.

• On a Mac’s Safari browser, it takes two clicks.

• On Android phones, it takes two taps.

So I followed Google’s instructions and also shared the company’s guidance with a panel of three design veterans. The verdict: It’s hard to switch — and most people would probably give up before completing the change.

“God help me, I’m dead,” Ted Selker, a product design veteran who worked at IBM and Xerox PARC, said after reading the steps to change the search engine on an iPhone.

Harry Brignull, a user-experience consultant in Britain, concluded about Google search: “Most people will just stick with it.”

I had similar takeaways. Here’s what the design experts and I found after trying to break up with Google search.

On an iPhone

Google said iPhone owners could switch to a different search engine in four taps by opening the Settings app, tapping Safari, tapping Search Engine and then selecting a search engine.

In reality, it’s more complicated.

Once the Settings app is open, Safari doesn’t immediately appear on the screen. It’s buried under 36 other menu items, so the user has to swipe upward at least twice to find the Safari menu. In reality, it takes six taps.

But even four steps would probably be too much for many of us, Mr. Selker said. It might have been simple 15 years ago, when most web browsing was done on stationary computers, but in the smartphone era, someone looking for that setting could be interrupted while on the go — to hop on a bus, for instance.

“You cannot expect people to have multi-stepped memory,” he said.

On a Mac

With just two clicks, Google said, Mac users can switch the default search engine on the Safari browser to a different service — by first clicking on the magnifying glass icon and then selecting a different search engine, like Yahoo, Bing or DuckDuckGo.

That’s much simpler than on an iPhone. But not everyone knows that the magnifying glass icon is a button — it allows people to enter a query in the search bar.

More problematic is that switching search engines can be confusing, because the steps are inconsistent between Safari on an iPhone and Safari on a Mac, said Tony Hu, a director at the Massachusetts Institute of Technology who oversees an engineering leadership program.

“Overall, the average person would probably struggle with this,” he said.

Mr. Selker said a better design would have been to make changing the search engine more “in your face,” like a prompt asking users to choose a search engine when opening the browser.

“It has to make you aware it’s there until you’ve dismissed it,” he said.

On Android

On an Android phone, Google said, it takes one long press on the search bar to prompt the Remove button to appear. Users can then tap on it to remove the Google search bar widget from the home screen.

This example is especially flawed. First, Google’s steps to remove the search bar widget work on some Samsung phones, but they do not work across all Android devices. On Google’s Pixel phones, for example, when a user long presses on the search bar, no Remove option appears.

Most important, removing the search widget deletes a shortcut to the Google search bar on the home screen, but it does not change the search engine in an Android web browser. Changing to a different search engine requires a different set of steps. Similar to the path on iPhones, it’s a four-step process that involves opening the browser and changing its settings.

The default option

The overarching lesson from the government’s antitrust trial against Google is that when companies make arrangements to become a default option, they are aware you will probably stick with the status quo because switching to an alternative requires awareness and effort, said Mr. Brignull, the author of “Deceptive Patterns: Exposing the Tricks Tech Companies Use to Control You.”

Google said in a statement that it was easy for people to change their default search engine on Android devices and Apple’s Safari. The company added that on Windows computers, which require a long process to switch from Bing as the default search engine in Microsoft’s Edge browser, the overwhelming majority of people chose Google as their search engine.

With all of that in mind, and the instructions now in front of you, you can try other search engines. If it turns out that you prefer Google anyway, at least it will be your decision — not Google’s.