8.2 Selective Attention: Matching Letter, Number & Symbol Strings Exactly
Key Takeaways
IOS defines selective attention as the ability to complete a task in the presence of distractions or monotony.
IOS items show a string of letters, numbers and symbols and ask which option repeats it exactly, with every character in the same orientation.
IOS's sample wrong options differ by reversed parentheses, a reversed bracket, one substituted symbol or one substituted letter.
Splitting the target into chunks of three or four characters and comparing chunk by chunk is faster and more accurate than reading the whole string.
Eliminate an option at its first mismatch; if two options survive, recheck them character by character from the end.
Note
OpenExamPrep provides this independent study guide to help prospective law enforcement candidates prepare for the National Criminal Justice Officer Selection Inventory (NCJOSI). OpenExamPrep is an independent educational publisher and is not affiliated with or endorsed by Industrial/Organizational Solutions (IOS) or any municipal civil service commission.
What IOS Measures
IOS defines selective attention as the ability to complete a task in the presence of distractions or monotony. It is the ability to concentrate even when there is a lot of distraction around you, and to keep paying attention to important details during repetitive, monotonous work. IOS's examples from the job are doing paperwork in a patrol car while the radio is on, and carrying out a security check while a lot of commotion is going on.
On the NCJOSI², IOS says you will look at a series of letters, numbers and/or symbols and pick the same pattern. The instructions in IOS's sample tell you to choose the only option that contains the exact pattern of the first string, keeping the orientation of the letters, symbols and numbers constant. In other words, nothing may be reversed, rotated, swapped or changed.
The items are not difficult in concept. They are difficult because the strings are long (IOS's samples run to roughly 25 to 30 characters), the wrong options differ by a single character, and the task is monotonous. That is exactly what the dimension measures.
The Six Ways a Wrong Option Differs
IOS's sample explanations show the kinds of differences to expect: parentheses printed as () instead of )(, a ] printed as [, one symbol replaced by a different symbol, and a w where the target has u. Nearly every mismatch falls into one of six types:
| Difference Type | What Changes | Examples to Watch |
|---|---|---|
| Substitution | One character replaced by a look-alike | 5/S, 0/O/o, 1/l/I, 8/B, 2/Z, u/v/w, q/g |
| Orientation reversal | A paired or directional mark flipped | (/), [/], {/}, b/d, p/q |
| Transposition | Two neighbouring characters swapped | 47 vs 74, )( vs (), rn vs nr |
| Omission | A character missing | #4x vs #x |
| Insertion or doubling | An extra or repeated character | @3 vs @33 |
| Case change | Upper and lower case swapped | V vs v, K vs k, W vs w |
Knowing these types tells you where to look. Pairs of brackets and parentheses, look-alike letters and digits, and adjacent characters are the hot spots.
The Chunk-and-Eliminate Method
Reading a 25-character string as one unit overloads short-term memory. Instead:
- Chunk the target. Mentally divide it into groups of three or four characters. Many people lightly mark the divisions in the booklet with a pencil tick.
- Compare one chunk at a time across all options. Check chunk 1 in options a to d, then chunk 2, and so on. This keeps only three or four characters in mind at once.
- Eliminate at the first mismatch. As soon as an option differs, cross it out and stop reading it. You do not need to know every error in a wrong option.
- Read character by character inside each chunk. Say each character silently ("R, four, percent, t"), including symbols. Saying "close parenthesis, open parenthesis" makes reversed pairs stand out.
- Confirm the survivor. Exactly one option matches. If two options survive, recheck both from the end of the string backward; fresh eyes on a different direction catch what you missed.
Worked Example
Target string:
R4%t)(8Kq@3]v7
Options:
a. R4%t()8Kq@3]v7
b. R4%t)(8Kq@3]v7
c. R4%t)(8Kg@3]v7
d. R4%t)(8Kq@3[v7
Chunk the target as R4%t / )(8K / q@3] / v7.
- Chunk 1 (
R4%t): all four options match. - Chunk 2 (
)(8K): option a shows()8K, a reversed pair. Eliminate a. - Chunk 3 (
q@3]): option c showsgforq, and option d shows[for]. Eliminate both. - Chunk 4 (
v7): option b matches.
The answer is b. Notice that you never had to read all of options a, c or d.
Managing Monotony and Distraction
Because the dimension is about attention over time, accuracy can drop late in a set of similar items. Practical habits:
- Use a pointer. Move your pencil tip under the characters you are comparing so your eyes cannot skip.
- Keep a steady rhythm. Rushing causes substitution errors; slowing too much invites second-guessing. Most candidates can complete a careful comparison in well under a minute once the method is automatic.
- Practice with background noise. IOS's own examples (paperwork with the radio on) describe distraction. Timed drills with a radio or conversation in the background build the same tolerance.
- Do not trust familiar shapes. Strings that resemble words or license plates invite your brain to "auto-complete" them. Treat every string as random characters.
How Selective Attention Differs from Neighbouring Dimensions
| Dimension | What You Search For | Typical Item |
|---|---|---|
| Selective attention | An exact copy of a character string | Pick the identical string of letters, numbers and symbols |
| Flexibility of closure | A known shape hidden inside a drawing | Pick the object that appears in the figure |
| Verbal expression | A misspelled or wrong word | Find the misspelling or choose the correct word |
All three reward slow, deliberate comparison, but selective attention is the only one where a single reversed bracket decides the answer.
Choose the option that contains exactly the same pattern as the target string, keeping every character in the same orientation.
9Lq#}{3Tw&5]Hb
9Lq#{}3Tw&5]Hb
9Lq#}{3Tw&5]Hb
9Lq#}{3Tw&S]Hb
9Lg#}{3Tw&5]Hb
Choose the option that contains exactly the same pattern as the target string.
mN0o@4!rV)8(wx2
mNo0@4!rV)8(wx2
mN0o@4!rv)8(wx2
mN0o@4!rV)8(wx2
mN0o@4!rV)8(vx2
A candidate is comparing a 26-character target string with four options. Which approach best fits how IOS describes selective attention items?
Compare chunks of three or four characters and cross out each option at its first mismatch
Choose the option that looks most like the target at a glance, because small differences are not scored
Pick any option that contains the same characters, because order and orientation do not matter
Skip all selective attention items, because they are not counted in the cognitive score
Sections you finish are checked off in the contents.