MKF2111 · Buyer Behaviour
Exposure, Attention & Perception
This chapter is the front end of the Psychological Core: how a stimulus first reaches a consumer (exposure), how the brain allocates limited processing to it (attention), and how meaning is assigned (interpretation/comprehension). It introduces the unit's one genuinely quantitative idea — the just noticeable difference (j.n.d.) and Weber's Law, K = ΔS/S — which the oral can ask you to state and apply to pack-downsizing or a price cut.
What this chapter covers
- 011. Exposure: contact with a stimulus via any of the five senses; raises awareness, liking and perceived truthfulness
- 022. Mere-exposure effect (Zajonc): repetition increases liking — but only up to the inverted-U wear-out point
- 033. Truth effect & selective exposure: repeated claims feel truer; consumers actively avoid stimuli (ad-blockers)
- 044. Attention: allocation of limited, selective, switchable processing capacity; focal vs non-focal
- 055. Enhancing attention: personally relevant, pleasant, novel/surprising, easy-to-process (prominent, contrasting, concrete)
- 066. Interpretation & Gestalt: closure and figure-ground; the brain seeks completeness and pattern
- 077. Thresholds: absolute threshold (detect at all) vs differential threshold (notice a difference) and the j.n.d.
- 088. Weber's Law K = ΔS/S: bigger starting stimulus → bigger change needed to be noticed; stay below the j.n.d. to hide a change, exceed it to be seen
Weber's Law and the j.n.d.: hide a downsizing, show a price cut
- +2: formula and valueState Weber's Law: K = ΔS / S, so the smallest noticeable change is ΔS = K × S = 0.08 × 750 = 60 g.
- +1: sub-threshold downsizingTo stay below the j.n.d., remove less than 60 g — e.g. drop to about 700 g (a 50 g cut, under the 60 g threshold), so the change is sub-threshold and unnoticed.
- +1: above-threshold price cutFor a price cut the brand wants the change to exceed the j.n.d. so it is noticed: a token 2% discount may fall below the threshold and be invisible, while a discount comfortably above the j.n.d. (e.g. 15%) registers as a real saving.
- +1: the marketing ruleState the one-line rule: stay below the j.n.d. for changes you want hidden (downsizing, quality cuts); exceed it for changes you want seen (improvements, price cuts).
Key terms
- Exposure
- The process by which a consumer comes into contact with a stimulus, through any of the five senses. Repeated exposure raises awareness, liking and perceived truthfulness.
- Mere-exposure effect
- Zajonc's finding that repeated exposure to a stimulus increases liking for it — but only up to a point: too many repetitions cause boredom and wear-out (the inverted-U).
- Attention
- The allocation of limited mental processing capacity to a stimulus. It is selective, limited and switchable (not truly divided); focal attention is conscious and resource-heavy, non-focal is automatic and pre-attentive.
- Gestalt principles
- The brain's tendency to seek completeness and pattern when interpreting stimuli — including closure (filling in missing parts of a form) and figure-ground (separating an object from its background).
- Just noticeable difference (j.n.d.)
- The minimum change in a stimulus needed before the change is perceived as different — the point at which the differential threshold is crossed.
- Weber's Law (K = ΔS/S)
- The j.n.d. is a constant proportion of the starting stimulus: K = ΔS/S, where ΔS is the smallest detectable change and S is the initial stimulus. The bigger the starting stimulus, the bigger the change must be to be noticed.
Exposure, Attention & Perception FAQ
What's the difference between the absolute and the differential threshold?
The absolute threshold is the minimum intensity needed to detect a stimulus at all (e.g. the faintest sound you can hear). The differential threshold is the minimum difference between two stimuli that you can notice — and the just noticeable difference (j.n.d.) is that smallest detectable change. Weber's Law describes the differential threshold.
How do marketers actually use the j.n.d.?
Both directions. To hide an unfavourable change (shrinking a pack, trimming quality) they stay below the j.n.d. so shoppers don't notice. To make a favourable change land (a price cut, a quality improvement) they make it exceed the j.n.d. so it is clearly perceived. The same maths, opposite goals.
Why does liking eventually fall with more exposure?
The mere-exposure effect is an inverted-U: repetition first builds familiarity and liking, but past an optimum it causes wear-out and boredom, so liking declines. The marketing lesson is to refresh creative before an ad fatigues, not to run the identical execution forever.
Is Weber's Law the only formula I need here?
Essentially yes — K = ΔS/S is the one calculation in this chapter, and the unit has almost no maths overall. You should be able to state it, compute ΔS = K × S, and explain the hide-vs-show rule out loud. The rest of the chapter is conceptual (exposure, attention, Gestalt).
Exam move
Split this chapter into the three-stage pipeline — exposure → attention → interpretation — and have one crisp line and one example for each, because the oral may probe any stage. Master the one calculation cold: practise ΔS = K × S both ways (hide a downsizing, show a price cut) until you can say it in under a minute, since a clean quantitative anchor stands out in an otherwise conceptual unit. For attention and Gestalt, rehearse a real ad you can describe (a surprising or contrasting execution, a closure or figure-ground visual) so you can apply, not just define. End every answer with the marketing implication — the mere-exposure inverted-U means refresh creative, the j.n.d. means hide or show by design.
