Memory, oriented

Every list stays on screen for about a second per item, three seconds at the least. Then you get one of three questions: which item came right after a named one, which item sat in a given position, or which option was never shown. You cannot tell in advance which question is coming, and two of the three need the order, not just the items. No item repeats within a list, so in those two questions every wrong option is something you really saw, sitting in another slot.

How much you can hold at once is usually estimated at between about four and about seven units, depending on what is counted. Those units are chunks, not items. Seven separate digits are a heavy load, while 4 9 1 7 3 8 2 held as 491, 738 and 2 is only three chunks. That is why every technique in the chapters that follow starts by grouping.

The common mistake is to spend the first seconds trying to take in every item at once and then find that the order has gone. Grouping first is what keeps the order, because each group carries its own sequence.

Rule: group first and rehearse second; never study a list one item at a time.

Digits are easiest to keep in groups: 5 8 2 7 3 9 0 4 is held as 582, 739 and 04. People recall a spoken string of digits better when it comes in groups than when it runs together, and you can impose the same grouping yourself as you read. In one study, a natural phone-number melody, rising at the end of each group and falling on the last, helped beyond what pauses alone did. Before grouping, scan for a group you already know, such as a year, a run or counting by twos, because knowledge you already have can turn several digits into one chunk.

Letters need a sound. Add vowels in your head so a run becomes sayable: H R B becomes "harbor." Split a long run into threes before turning it into words, so C L P D R W S N K becomes "clip," "draw" and "sink." A familiar abbreviation such as U S A or D N A counts as one chunk.

The trap is the rhyming letters. The names of B, C, D, E, G, P, T, V and Z all end in the same "ee" sound. Lists of similar-sounding items are recalled worse than lists of distinct ones, mostly because their order gets mixed up. When several appear together, anchor each one to its place in a chunk you built, not to its sound.

Rule: give every group a single sound, and never lean on the sound of a rhyming letter alone.

Word lists run from six to eleven items, so they need a structure that carries the order. The most useful one links neighbors: picture each word acting on the next, a kettle pouring into a saddle, then the saddle sliding onto a walrus. Forming an image of two words interacting is a well-tested way to remember pairs, and a chain of such images points forward, which is exactly what a question about what came next needs. A short story does the same job, as long as the words appear in it in list order.

The catch is time. In one study people needed a little over four seconds, on average, to form a single interacting image for a pair of words, and you get about one second per word. Treat images as a tool for the hardest pairs, not a rule for every pair. Say the words to yourself as well: the speech-based store you rely on holds fewer long words than short ones, so say them briskly and do not stretch them out.

The usual mistake is to build one elaborate scene for the first two words and run out of time for the rest. A crude link for every pair is worth more than a vivid one for the first pair alone, because the question can land anywhere in the list.

Rule: link every neighbor somehow, by image where you have time and by sound where you do not.

Items held in your inner voice fade within seconds unless you refresh them, and the question does not appear until the list is gone. Rehearsal is what carries the list across that gap. Run it cumulatively: say the first item, then the first two, then the first three, so the early items get the most practice and the order is practiced on every pass. On a long list, rehearse by groups instead: the first group, then the first two groups, then all of them.

End the study time with one complete run through the list, first to last, in the groups you made. That final pass refreshes the end of the list, which cumulative rehearsal practices least, and it lays down the route you will search when the question asks for a position or a neighbor.

Two habits ruin rehearsal. The first is stalling on one stubborn item while the rest fade; leave it, mark the gap, and keep the loop moving. The second is restarting from the middle after losing your place, which scrambles the order; go back to the first item instead.

Rule: never let the loop stop between the list and the question, and restart from the top when it breaks.

Position questions become lookups if you numbered while rehearsing. Tie the first item of each group to its number, then find a position by group and place: with groups of three, the eighth item is the middle of the third group. For a late position, count back from the end, which is shorter when you know the length. Expect the middle of the list to be your weakest stretch, since people recall the first items best and the middle ones worst.

For what came after a named item, recall the pair that starts with it, or replay from the start of its group until you reach it. Order errors mostly swap items that sat close together, so the tempting wrong answers are the item two places on and the item just before the named one. No item that came earlier than the named one can be the answer, and the first item never can.

For what was not shown, place each option in your list. Three will find a slot and the fourth is the answer, so you never need to recall the missing item itself. Distrust an option that only feels familiar: the lists reuse small sets of items, and something from an earlier list can intrude.

Rule: answer from where an item sat, never from how familiar it feels.

A wrong answer tells you what went wrong if you look at which option you chose. An item from a nearby slot means the order slipped, so tighten the links between neighbors. An item you remember from an earlier list means old material intruded, so drop each list completely when the next one appears. A blank, where nothing came to mind, means the item was never stored, so group it and give it a sound before the clock runs out.

The lists change as you improve. Easier questions use short lists of digits, and as your rating rises the lists lengthen, move to letters and then words, and reach eleven items. A routine that copes with five digits has to cope with eleven words, so build it while the lists are short. Group the list, give each group a sound, number the groups, rehearse from the start, and finish with a full pass.

Running the same routine every time matters because the clock gives you about a second per item. A fixed sequence keeps your attention on the items instead of on deciding what to do next.

Rule: diagnose every miss by the option you picked, and fix that stage of the routine.