The question of whether memory can be improved has fascinated psychologists for over a century. The short answer is: it depends on what you mean by "memory." Your brain's raw storage capacity — the number of items you can hold in working memory at once — is largely determined by genetics and doesn't change much with training. But your ability to use that capacity efficiently — through strategies like chunking, rehearsal, and spatial association — is highly trainable, and that's where real improvement comes from.
Working Memory: The Bottleneck
Working memory is the mental workspace where you hold information while actively processing it. It's what lets you remember a phone number long enough to dial it, keep track of multiple variables during a conversation, or hold a chess position in your mind while calculating moves. The classic finding, published by George Miller in 1956, is that the average person can hold about seven items (plus or minus two) in working memory at once. Decades of research since then have refined this to something closer to four "chunks" of information, with the definition of a chunk depending on expertise and strategy. This capacity limit is real and biological — you can't will your brain to suddenly hold twelve independent items — but you can change how much information each chunk contains.
Chunking: The Core Strategy
Chunking is the single most powerful memory technique, and it works by reorganising information so that each "slot" in working memory holds more data. Consider the digit sequence 1-9-6-9-0-7-2-0. Stored as eight individual digits, it exceeds most people's capacity. But if you recognise 1969 as the moon landing and 0720 as a time of day, the same sequence becomes two chunks and fits comfortably into working memory. Expert memorisers use elaborate chunking systems to recall sequences of 80 or more digits in tasks like the Number Memory test. They're not holding more items than you — they're packing more information per item. The practical implication is that anyone can dramatically improve their performance on digit-span and sequence-recall tasks by building a personal library of meaningful number associations: dates, addresses, jersey numbers, PIN patterns, and so on.
Rehearsal and the Phonological Loop
When you silently repeat a phone number to yourself to keep it alive in memory, you're using what psychologists call the phonological loop — a subvocal rehearsal system that refreshes auditory and verbal information before it decays. This loop has a time limit: you can only rehearse as many items as you can silently say in about two seconds. That's why longer words are harder to remember in lists than shorter words, and why sequences of similar-sounding digits (like 8-3-B-D-V-T) are harder to recall than dissimilar ones. For practical training purposes, this means that speed matters. The faster you can mentally encode and rehearse a sequence, the more items you can cycle through before the earliest ones fade. Practice on tasks like the Number Memory Test effectively trains this rehearsal speed, even if it doesn't change the underlying hardware.
The Method of Loci
The method of loci (also called a memory palace) is a spatial mnemonic technique that dates back to ancient Greek orators. The idea is simple: visualise a familiar route — your walk from the front door to the kitchen, for example — and mentally place each item you want to remember at a specific location along that route. To recall the items, you mentally walk the route and "see" each one in its place. This technique exploits the brain's powerful spatial memory system, which evolved for navigating physical environments and is far more robust than verbal rehearsal for long lists. Memory athletes who memorise the order of a shuffled deck of cards in under a minute use exactly this technique. For digit-span tasks it's slower to set up than pure chunking, but for longer sequences or competition-level recall it's indispensable.
What the Science Says About Transfer
Here's the honest part. Hundreds of studies have investigated whether training on working-memory tasks makes you generally smarter — whether improvement on a digit-span game transfers to better reading comprehension, fluid intelligence, or academic performance. The results are mixed at best. Several large meta-analyses (including one by Melby-Lervåg and Hulme in 2013 and another by Sala and Gobet in 2017) found that training produces strong improvements on the trained task and closely related tasks, but little to no transfer to broader cognitive abilities. In other words, practising Number Memory will make you much better at Number Memory, and probably better at similar digit-recall situations in daily life, but it won't raise your IQ or make you better at unrelated tasks like spatial reasoning. This doesn't mean the training is useless — it means you should set expectations correctly. You're building a specific skill, not upgrading your brain's general processor.
Practical Tips for Better Memory Performance
Sleep is critical. Memory consolidation — the process by which short-term memories are stabilised into long-term storage — happens during deep sleep. Chronic sleep deprivation directly impairs both encoding (taking in new information) and retrieval (accessing stored information). If you're trying to improve your scores on any memory task, sleeping well is non-negotiable. Minimise interference. Working memory is easily disrupted by competing stimuli. Close extra tabs, mute your phone, and practise in a quiet environment. Practise at the edge of failure. The most effective training happens when the task difficulty is just slightly beyond your current ability — easy enough that you succeed more often than you fail, but hard enough that success requires full concentration. On the Number Memory test, this means staying engaged through the rounds where the sequence length starts pushing your limit, rather than checking out once it gets uncomfortable.
Find out your current digit-span capacity on the Number Memory Test and start building your chunking skills today.