Cognitive Effects — @cite{sperber-wilson-1986}

Cognitive effects are changes in an individual's beliefs from processing an input in a context. Three types:

1. Strengthening: Existing assumption gains evidential support
2. Contradiction: Existing assumption contradicted and eliminated
3. Contextual implication: New conclusion from input + context jointly

An input with no cognitive effects is irrelevant. More effects = more relevant (other things being equal).

The 2nd edition (Postface, p. 265) renames "contextual effects" to "cognitive effects" to emphasize these are changes in the individual's cognitive state.

All three types are POSITIVE cognitive effects (S&W Ch. 3 §1-3). Contradiction is positive because eliminating a false assumption improves the individual's representation of the world. These three exhaust the ways an input can be relevant — an input that produces none of these is irrelevant.

inductive Theories.Pragmatics.RelevanceTheory.EffectType : Type

The three types of cognitive effect (S&W, Ch. 3). These exhaust the ways new information can be relevant in a context. An input producing none of these is irrelevant.

All three are positive: strengthening and contextual implication obviously so; contradiction is positive because eliminating a false assumption is epistemically beneficial.

• strengthening : EffectType

  Existing assumption strengthened by new evidence

• contradiction : EffectType

  Existing assumption contradicted and eliminated

• contextualImplication : EffectType

  New conclusion derived from input + context jointly

instance Theories.Pragmatics.RelevanceTheory.instDecidableEqEffectType : DecidableEq EffectType

Equations

• Theories.Pragmatics.RelevanceTheory.instDecidableEqEffectType x✝ y✝ = if h : x✝.ctorIdx = y✝.ctorIdx then isTrue ⋯ else isFalse ⋯

def Theories.Pragmatics.RelevanceTheory.instBEqEffectType.beq : EffectType → EffectType → Bool

Equations

• Theories.Pragmatics.RelevanceTheory.instBEqEffectType.beq x✝ y✝ = (x✝.ctorIdx == y✝.ctorIdx)

instance Theories.Pragmatics.RelevanceTheory.instBEqEffectType : BEq EffectType

Equations

• Theories.Pragmatics.RelevanceTheory.instBEqEffectType = { beq := Theories.Pragmatics.RelevanceTheory.instBEqEffectType.beq }

def Theories.Pragmatics.RelevanceTheory.instReprEffectType.repr : EffectType → ℕ → Std.Format

Equations

• One or more equations did not get rendered due to their size.

instance Theories.Pragmatics.RelevanceTheory.instReprEffectType : Repr EffectType

Equations

• Theories.Pragmatics.RelevanceTheory.instReprEffectType = { reprPrec := Theories.Pragmatics.RelevanceTheory.instReprEffectType.repr }

structure Theories.Pragmatics.RelevanceTheory.EffectProfile : Type

An effect profile: the cognitive effects of processing an input in context, with an overall magnitude assessment.

The practitioner classifies the effects and estimates their magnitude; the comprehension procedure uses the magnitude for relevance assessment.

• effects : List EffectType

  Which types of effects are produced

• magnitude : ℕ

  Overall magnitude (higher = more relevant, all else equal)

instance Theories.Pragmatics.RelevanceTheory.instReprEffectProfile : Repr EffectProfile

Equations

• Theories.Pragmatics.RelevanceTheory.instReprEffectProfile = { reprPrec := Theories.Pragmatics.RelevanceTheory.instReprEffectProfile.repr }

def Theories.Pragmatics.RelevanceTheory.instReprEffectProfile.repr : EffectProfile → ℕ → Std.Format

Equations

• One or more equations did not get rendered due to their size.

def Theories.Pragmatics.RelevanceTheory.EffectProfile.irrelevant (p : EffectProfile) : Prop

An input with no effects is irrelevant (S&W, Ch. 3).

Equations

• p.irrelevant = (p.effects = [] ∧ p.magnitude = 0)