Editor note: “Chasing” near session end is a known cognitive bias—no deadline justifies abandoning basic strategy or your bankroll plan.

Have you ever been playing online blackjack for a few hours at an online casino and know you will have to quit soon? If you are behind when this happens you may be at risk of something known as the end-of-the-day betting effect. This approach involves trying to make up for a losing session by taking extra risks and betting bigger. You are probably going to lose even more money when you fall victim to this effect. Here’s a closer look at what it is and how you can avoid it.

The End of the Day Betting Effect

March 21, 2026 · Counting Edge Editorial

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According to the psychologists that named it, the end-of-the-day betting effect is a cognitive bias. It is the tendency to bet larger amounts and take more risks at the end of the betting session than at the beginning. It was first described by William McGlothlin as early as 1956 and again by Mukhtar Ali in 1977. Both men made their initial observations at horse racing tracks while observing horse racing bettors.

There is a part of the brain that reasons losses need to be recouped before the bettor leaves the race track or the online casino. When this bias kicks in, the bettor may bet races that are not ideal or take deviations from basic blackjack strategy. Those who succumb to the end-of-the-day betting effect may not realize that they are victims. This appears to be a psychological effect that is rooted in the actual way the brain approaches gambling and risk.

The Effect and Horse Racing Betting

It probably should not come as that much of a surprise that the effect was first noted at horse racing betting. There are certain things about horse racing betting which make it very suitable to this condition. In the early days of horse racing betting the bets were placed at a live track that only offered so many races to the betting public each day. A bettor would know when they were running out of opportunities in real time as the races progressed. They could also know if they were winning or losing. A bettor that was behind could easily calculate how much money it would take to get even for the day.

They might need to bet twice or three times their normal amount to achieve that goal. They would do this even though the remaining races did not merit or justify a bigger bet. More often than not, the bettor would lose. Today, things can be even worse for the horse bettor. We are living in an age of the online sportsbook. This presents many more betting opportunities.

In other words, the end-of-the-day is longer coming around. By the time the bettor reaches it, they can be hundreds of dollars behind. They will then try to recoup and become susceptible to the effect’s pitfalls. Because they have even longer to try and recover, they push things even more.

Online Blackjack and the End-Of-The-Day Betting Effect

Many states in the US have taken measures to legalize online blackjack and online casinos. With this comes another application of the effect. It may be even more risky in the game of blackjack because there are more ways that a player can make deviations from basic blackjack strategy. In horse racing, the bettor has one event to wager on every twenty minutes or so during a race card.

You can play almost ten hands of blackjack in that same amount of time. Each blackjack hand that you play is another chance to recoup your losses. You start to split tens, lose the count, and stand on a 16 against a 20. Things can go downhill very quickly.

The Issue of Fatigue and Online Gambling

Some people believe that the end-of-the-day betting effect can be enhanced by fatigue. With the era of online gambling in full swing, fatigue is a genuine issue that needs to be addressed by the gambler. When you become tired while playing blackjack or betting horses online, the chances that you will make poor decisions goes up. Becoming fatigued is easier online because the sessions never end.

It can be much easier to get up and walk away from a live casino than it is to shut off your computer or mobile device. There is an easy fix for gambling fatigue. All the player has to do is take a break. It is easier said than done for the player who is betting online and is behind. When the effect kicks in, these players may not be able to stop playing until they have either caught up or gone broke.

Cognitive Bias and Bettors Creating Their Own Reality

What is really going on behind the scenes when it comes to the end-of-the-day betting effect? Essentially, a cognitive bias is causing the bettor to create and shape their own reality in which existing betting knowledge and reason is compromised. The bettor begins to rationalize that there is an acceptable scenario where basic blackjack strategy or the fundamental aspects of horse racing handicapping may safely be abandoned. Under normal circumstances when the bettor is ahead, they would not consider some of the plays or bets that they would when trying to recoup.

Creating an alternate reality when it comes to gambling can be the first step toward a dangerous gambling problem. Beware if you notice yourself making excuses for betting to recoup losses at the end of the day.

Risk Aversion as a Warning Sign

It is always important to pay attention to risk aversion when gambling. You should often lose less sight of your personal comfort level where betting is concerned. If your own comfort level of betting is being challenged, you may be falling victim to this psychological condition. Be watchful when this happens and learn to moderate your play. Always remember that there is no one to safely keep you from the effect and the disaster it can cause. This is especially true if you are playing alone from home.

You will need to develop discipline and self-control. Also, don’t be afraid to discuss with a professional if you think things are beyond your ability to handle.

FAQs: end-of-session betting

Is chasing losses at the end of a session rational?

No—it is a documented bias: deadlines amplify risk-taking even when the odds are unchanged.

What practical guardrails help online?

Hard loss limits, session timers, cooling-off breaks, and logging when you last ate or slept—fatigue pairs badly with rebuy buttons.

Does blackjack make the effect worse than horse racing?

Rapid repeat betting can compress many marginal decisions into minutes, so poor discipline snowballs faster than in slower betting formats.

Frequently asked questions

What is the end-of-the-day betting effect?

A cognitive bias where bettors increase stakes or take worse risks as a session nears its end, often trying to recover earlier losses.

How can I avoid it while playing online blackjack?

Use preset loss and win caps, alarms, and forced breaks; never raise bets specifically because the clock is running out.

Does fatigue matter?

Yes—tired players deviate from strategy more often; end sessions before exhaustion rather than after.

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