NATA cheat sheet

Working memory span: average adult holds 4±1 chunks simultaneously; chunking (grouping items) raises effective capacity without changing span.

Mental rotation speed follows a linear function of angular disparity: response time rises roughly 2–4 ms per degree of rotation from the upright.

Embedded figures tasks measure field independence-the ability to isolate a target shape from a distracting surrounding pattern.

Spatial visualization differs from spatial relations: visualization manipulates whole objects in 3D, relations concerns mental rotation and perspective taking.

Pattern completion rule: check alternation, rotation, addition, and mirroring in that order; most sequences use one rule applied consistently.

Figure-ground perception is the cognitive act of assigning edges to figure versus background; reversible figures show it is not fixed.

Attention is selective and limited: divided attention degrades performance when two tasks share the same modality or resource pool.

Problem-solving heuristic: means-end analysis reduces the gap between current state and goal state one subgoal at a time.

Gestalt laws: proximity, similarity, continuity, closure, common fate, and figure-ground-elements are grouped by these cues.

Golden ratio ≈ 1.618; rule of thirds places key elements near intersections of a 3×3 grid rather than at center.

Color wheel relationships: complementary = opposite (max contrast), analogous = adjacent (harmony), triadic = three evenly spaced hues.

Value contrast drives legibility more than hue contrast; text on background needs roughly 4.5:1 luminance contrast for body text.

Warm colors (red, orange, yellow) advance perceptually; cool colors (blue, green) recede-useful for depth cues in composition.

Symmetry types: bilateral (mirror), radial (rotational about a center), and translational (repeated offset)-each reads differently.

Linear perspective: parallel lines converge at a vanishing point on the horizon; size diminishes with distance at a constant ratio.

Balance can be symmetrical (equal visual weight) or asymmetrical (unequal weight offset by size, color, or placement).

Simultaneous contrast: a color appears lighter against dark ground and darker against light ground-judge color only in context.

Modus ponens is valid: if P then Q; P; therefore Q. Modus tollens is valid: if P then Q; not Q; therefore not P.

Affirming the consequent (if P then Q; Q; therefore P) and denying the antecedent (not P; therefore not Q) are both invalid.

Syllogism validity depends on form, not truth of premises: all A are B; all B are C; therefore all A are C is valid.

Contrapositive is logically equivalent to the original conditional: 'if P then Q' ≡ 'if not Q then not P'.

Number series strategy: compute first differences, then second differences; if constant, the series is polynomial of that degree.

Analogy form A:B :: C:? - identify the relation in the first pair (function, part-whole, cause-effect, degree) and apply it.

Venn reasoning: 'some A are B' does not imply 'some B are A' is false-it is symmetric; but 'all A are B' does not imply 'all B are A'.

Necessary vs sufficient: necessary condition must hold for the outcome; sufficient condition guarantees it; neither implies the other.

Correlation does not imply causation; alternative explanations include reverse causation, common cause, and coincidence.

Confirmation bias: tendency to seek evidence supporting an existing belief; a fair test seeks disconfirming evidence.

A valid argument can have false premises; soundness requires both valid form and true premises.

Straw man fallacy misrepresents an opponent's position; ad hominem attacks the person rather than the argument.

Hasty generalization draws a broad conclusion from a small or unrepresentative sample; sample size and randomness matter.

Post hoc fallacy assumes that because B followed A, A caused B-temporal order alone is not causal evidence.

Falsifiability: a claim that cannot in principle be disproved is not empirically testable.

Base-rate neglect: ignoring prior probability when interpreting a test result; combine base rate with likelihood ratio.