Series: progression of one or more figural elements across a sequence
What this domain tests
Series items give you four or five frames and ask which figure continues the sequence. The examiners are testing whether you can isolate each figural element, state the rule that governs it, and extrapolate exactly one step. Almost every wrong answer satisfies some of the elements and breaks one.
Decompose before you reason
List every element separately: outer frame, inner shapes, dots, shading, line segments, orientation, position. For each, write the sequence of states across the frames (for example dot: top, right, bottom, left). A rule must fit every given frame, not just the last two.
Typical progressions
- Constant step: one more side, 45 degrees more rotation, one more dot per frame.
- Accelerating step: +1, +2, +3 sides; +45, +90, +135 degrees.
- Cyclic rule: period 2 or 3, so the fourth frame repeats the first.
- Two interleaved series: odd frames follow one rule, even frames another. Suspect this whenever the step appears to jump.
- Element lifecycle: a shape appears at frame 3 and grows, or a count rises then falls.
Worked example
Frame 1 shows a square outline with a small dot on the top edge and a triangle inside. Frame 2: dot on the right edge, quadrilateral inside. Frame 3: dot on the bottom edge, pentagon. Frame 4: dot on the left edge, hexagon. The dot advances one edge clockwise, so it returns to the top edge at frame 5. The polygon gains one side each frame, so frame 5 holds a seven-sided shape. The answer must show the dot on the top edge and a seven-sided polygon. A common distractor shows the triangle again, because the dot cycle repeats and lures you into thinking the whole figure resets.
Traps that cost marks
- Fitting a rule to frames 3 and 4 only, when frames 1 and 2 contradict it.
- Missing a second element that changes at a different rate, such as shading alternating while position advances.
- Treating a direction reversal as continued motion, when it is a reflection.
- Accepting an option that satisfies one element and violates another. Every element must be satisfied simultaneously.