Can you recall when the Boxer Rebellion occurred but forget where you left your car keys? Do you remember the name of the 13th president but have a hard time bringing a specific word to mind when you need it? You may be suffering from too much memory.

Research at the Columbia University Medical Center indicates that the growth of new neurons in the hippocampus, the part of the brain where learning and memory are seated, can actually cause you to experience more limited working, or short-term, memory.

Apparently, forgetting some information is essential to being able to access short-term memory. Storing too much information interferes with working memory. In experiments in which mice had the neurogenesis in the hippocampus blocked, they were better able to navigate a maze and locate food in the maze.

The researchers suggest that forgetting some older and useless information makes room for newer and useful information such as where your car is parked in a large lot.

But which information is useless, and is all older information just taking up storage space you could use for something newer and more immediate? It is said of Albert Einstein that he was often distracted and forgetful. He described his wild hairstyle as simply the result of doing nothing with it. But the man who reportedly never untied his shoes because he couldn’t remember to tie them again, was busy pondering the nature of the universe.

According to The Association for Distracted People, “distractedness actually reflects a high level of concentration (on something else)”.

Is burning the midnight oil while pondering a big problem or studying for an important exam an effective way to sear knowledge into your brain? Despite the stereotype we often see of the dedicated scientist working long into the night to solve a particular equation, it is more likely that a good night’s sleep and a fresh start would be a more effective strategy.

Research indicates that the brain’s ability to refuse and fend off distracting influences decreases when we are tired. Normally, when we are involved in a task, our brains select to allow or disallow incoming information. Distracting information is disallowed. However as tiredness increases, this ability decreases and distraction can disrupt concentration.

Dutch researcher Harm Veling conducted experiments using words and memory tests. Subjects studied words that were strongly associated with each other, some similar words that served as distracting words and some neutral words that were not associated with the others at all. Suppressing the distractions was key to performing well on the test and performing the task quickly.

The brain’s ability to suppress distraction is adversely affected by tiredness. Subjects who were suffering mental fatigue did the least well on the tests as they were no longer able to suppress the distractions.

So the next time you are facing a difficult task requiring concentration, the best way to prepare is to rest up for it.

Brain Fends Off Distractions - Netherlands Organisation for Scientific Research

If you have trouble with math and numbers, you can blame your right parietal lobe.

People with dyscalculia have difficulty processing numbers. Now researchers can identify the cause of dyscalculia, which is said to affect 5% of the population.

Scientists have traced the roots of dyscalculia (difficulty with math) to malformations in the right parietal lobe of the brain.

Researchers using transcranial magnetic stimulation (TMS), stimulated the brain just as subjects without dyscalculia were about to complete a maths task, comparing two digits. They had to decide which digit was numerically larger, 2 or 4, but the 2 was written in a larger font than the 4.

Researchers found that subjects with normal math ability displayed behaviour similar to those with dyscalculia when they TMS was used to disrupt neuronal activity in the right intraparietal sulcus.

University College, London - The Root of Dyscalculia Found

The only way to get rid of temptation is to yield to it… I can resist everything but temptation. Oscar Wilde

Research has shown that our ability to resist impulse purchases goes down if we are exercising self-control in some other area, such as dieting.

But it isn’t just in shopping that we sometimes experience a moment of weakness or act contrary to our intentions. When our self-regulatory ability is being expended in one area, we can lose that ability in another. Dealing with stresses at work might leave you depleted and unable to resist that hot-fudge sundae.

Researchers have found a physical indicator of when people may be working hard at self-control and therefore, vulnerable in some other area by measuring heart rate variability (HRV).

HRV is higher when people are trying to resist temptation. The researchers noted that brain structures involved in self-regulation overlap with the structures that control HRV.

The article, Heart Rate Variability Reflects Self-Regulatory Strength, Effort, and Fatigue appears in the journal Psychological Science.