And he called on the Magpies to use the woeful defeat at the London Stadium as a "turning point" in the Premier League season.
Newcastle are still searching for their first victory of the season on the road and haven't won away since April after their 3-1 defeat at struggling West Ham - whose last home success prior to the Magpies' visit was back in February.
After three successive home wins in the Champions League, Premier League and Carabao Cup, things were looking up for Howe's side - but they came crashing back down to earth after their worst showing of the season so far on Sunday.
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Howe admitted he was surprised by his side's display in the capital but didn't sense a lack of effort from his side and doesn't think there's a mentality on the problem on the road, though admitted: "The numbers aren't good in terms of our away form recently so it would be foolish of me to dismiss that outright.
"I think we've got a very good group of professionals who care deeply and want to do well.
"But certainly we haven't replicated our home form away. We haven't got the points that we've got at home, but I think some of the performances have been very good, we just didn't turn them into wins.
"This was a dip in terms of a performance. That's the worst we've played during that run of games we haven't won and a period of reflection is important."
Asked whether he felt there was a lack of effort from his players at West Ham, he said: "I wouldn't go there right now, I wouldn't say that.
"I didn't like the body language of the group but that can manifest in many ways.
"We rested a lot of players in midweek to try and give them fresh energy but sometimes the routine of preparing for another game can catch up with you.
"I don't want to look like I'm making excuses, I'm just trying to figure out what happened today.
"It's never one thing, it's always a combination of factors but I'd never accuse my players of lacking effort."
However, Howe did admit: "I don't think it looked like a Newcastle team that we've seen in recent seasons.
"The body language, the collective spirit on the pitch, loads of things that contribute to our performance weren't there.
"I don't think that was tactical or necessary technical, it was a by-product of us just not being where we needed to be mentally.
"We did a lot of work with the players between games so it's a difficult one to work out. We'll go away and learn because it's hopefully a turning point we can use to our advantage."
Newcastle are in the last eight of the Carabao Cup and well placed to qualify for the knockout phase of the Champions League, but are 13th in the Premier League and are already playing catch-up.
Howe said: "Of course it's a concern when you're not where you want to be because you're always in a position where you're chasing results.
"I feel that's where we are the moment. We haven't hit our rhythm in the league, not consistently, we've had some highs and today is a low. We're searching for that consistency."