Impulsive decision · Self-control

Delay Discounting (MCQ)

Delay discounting quantifies how much a person devalues future rewards. Kirby, Petry & Bickel 1999's MCQ is the most-cited measure. ADHD and substance-use groups show substantially higher k.

DifficultyExpert = strict academic parameters

Intermediate: 18 items (small + medium)

For each question, pick the option you instinctively prefer. There's no right answer — be honest.

History

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Refs: Kirby, Petry & Bickel 1999; Kirby 2009.

Scientific basis

Delay Discounting · scientific basis

Impulsive decision · Time preference

Kirby & Maraković 1996 operationalized delay discounting; Kirby, Petry & Bickel 1999's 27-item MCQ is the most-used instrument. ADHD and addictive populations show significantly higher k.

Expert-mode parameters

These are the standard parameters from the canonical paradigm (used by the "Expert" difficulty).

Parameter	Standard value	Source
Items (Expert)	27 questions	Kirby 1999 MCQ
Reward bins	small / medium / large	Kirby 1999
Scoring	Geometric mean of best-fit k + consistency	Kirby 1999
Validity threshold	≥ 0.75 consistency	Kirby 1999

Healthy-population norms (by age)

ln(k) is the natural log of the discount rate — smaller (more negative) = more patient / less impulsive. Thresholds derived from Kirby 1999 (adults n≈36), Reimers 2009 (UK online n=42863) and Steinberg 2009 (adolescents n=935) mean/SD by age; Excellent (lower lnK) = mean − 1 SD (more negative). Impulse control develops through childhood into adulthood (~age 25), stays stable for decades, then rises slightly at 65+. Assessment mode matches the band to your actual age.

Limitations： Kirby 1999 (n≈36 adults) is foundational; Reimers 2009 (UK n=42863 online) is the strongest modern benchmark, giving adult 18-54 moderate-strong evidence. Adolescent bands are supported by Steinberg 2009 (US n=935) with moderate evidence; child bands (8-13) are sparse and under-10 peer-reviewed MCQ norms are essentially absent (flagged `est` in norms.ts); 65+ is extrapolated from Reimers 2009 with limited direct data. ADHD and addictive populations show elevated k but are not part of the baseline norms. Language and currency context (USD vs CNY) affect discounting — cross-reference with SART commission rate for impulse control from the inhibitory control angle.

Age band	lnK Excellent (smaller)	lnK Mean	SD	Evidence
8-9	≤ -4.9	~-3.8	1.1	moderate-weak
10-11	≤ -4.7	~-3.6	1.1	moderate-weak
12-13	≤ -5.0	~-3.9	1.1	moderate
14-15	≤ -5.2	~-4.1	1.1	moderate
16-17	≤ -5.5	~-4.4	1.1	moderate
18-24	≤ -5.8	~-4.7	1.1	moderate-strong
25-34	≤ -6.0	~-4.9	1.1	moderate-strong
35-44	≤ -6.1	~-5.0	1.1	moderate-strong
45-54	≤ -6.1	~-5.0	1.1	moderate-strong
55-64	≤ -6.0	~-4.9	1.1	moderate
65+	≤ -5.8	~-4.6	1.2	moderate-weak

Standard output metrics

·ln(k_overall) — Primary; lower = more patient
·k_small / k_medium / k_large — Per magnitude bin
·Consistency — Data quality; < 0.75 suggests retest

Citations

Kirby, K. N., & Maraković, N. N. (1996). Delay-discounting probabilistic rewards. Psychon Bull Rev, 3(1), 100-104. DOI
Kirby, K. N., Petry, N. M., & Bickel, W. K. (1999). Heroin addicts have higher discount rates. J Exp Psychol Gen, 128(1), 78-87. DOI
Steinberg, L., et al. (2009). Age differences in future orientation and delay discounting. Child Dev, 80(1), 28-44. DOI
MacKillop, J., et al. (2011). Delayed reward discounting and addictive behavior: A meta-analysis. Psychopharmacology, 216(3), 305-321. DOI

All reference ranges come from published peer-reviewed literature. For personal training reference only — not a medical diagnosis. Full methodology: docs/PARADIGMS.md.

This tool is for educational and entertainment purposes only and does not constitute medical advice or a clinical diagnosis.