Definition: The lexical bias effect is the phenomenon where speech errors are more likely to result in real words rather than non-words.
Significance: This suggests a cognitive preference for lexically valid outputs in speech production.
Experimental Study:
SLIP (Spoonerisms of Laboratory-Induced Predisposition) Technique: Participants read pairs of words silently and then aloud, designed to induce phoneme transpositions.
Example: "cool tart" leading to the error "tool cart."
Observation: Real-word errors occur more frequently than non-word errors.
Implication: Internal speech processing involves monitoring or feedback loops favoring lexically legitimate outputs.
Theoretical Support: Supports interactive processing theories, where lexical-level information influences phoneme-level selection.
Self-Monitoring Theory:
Speakers have an internal mechanism to evaluate speech before articulation.
Non-word errors are more likely to be intercepted and corrected internally.
Dell’s Interactive Activation Model:
Speech production is a multi-layered system with bidirectional activation between semantic, lexical, and phonological levels.
Real-word combinations receive stronger activation due to feedback.
Semantic-Phonological Feedback Accounts:
Prioritizes real-word outputs due to reinforcing interaction between word meanings and sound structures.
Real-word errors are more resilient and likely to be articulated.
Evaluation of Theories: Dell’s model is better supported by neuropsychological and experimental data.
Evidence: Infants can discriminate phonemes from birth.
High-Amplitude Sucking (HAS) Technique:
Measures changes in an infant’s sucking rate in response to auditory stimuli; an increased sucking rate indicates perception of change.
Study Example: Eimas et al. (1971) showed that one-month-old infants could differentiate between /ba/ and /pa/ based on voice onset time (VOT).
Prenatal Studies:
Fetal heart rate deceleration and MEG studies show fetuses (around 28 weeks gestation) can detect changes in auditory stimuli, especially prosodic features.
Native Language Preference: Newborns prefer their native language, suggesting phonological learning begins before birth.
Theoretical Alignment:
Supports nativist theories (Chomsky, Pinker).
Integrates early learning from environmental exposure.
Segmentation Problem: Infants must identify individual words within a continuous stream of spoken language without explicit boundaries.
Strategies:
Statistical Learning:
Saffran et al. (1996) showed infants track syllable co-occurrence probabilities.
High transitional probabilities indicate syllables belong to the same word; low probabilities indicate word boundaries.
Phonotactic Constraints:
Infants become sensitive to permissible sound sequences in their language.
Example: English-speaking infants learn that "ng" is unlikely at the beginning of words.
Prosodic Bootstrapping:
Infants use rhythm, stress, and intonation to infer word boundaries.
English two-syllable words often have a trochaic stress pattern (strong-weak).
By 7.5 months, infants use this pattern to segment speech, preferentially extracting words beginning with a stressed syllable.
Familiar Words as Anchors:
Learned words serve as reference points to segment adjacent speech.
Age: Begins around 10-12 months.
Fast Mapping:
Children form a connection between a new word and its referent after minimal exposure.
Carey and Bartlett (1978) demonstrated that children could remember a novel word's meaning after hearing it once in a clear context.
Innate Biases and Heuristics:
Mutual Exclusivity: Children assume each object has only one label, ruling out known terms when hearing a new word.
Syntactic Bootstrapping: Inferring word meaning based on grammatical structure.
Pragmatic Cues: Using gaze direction and speaker intention.
Vocabulary Development:
Non-linear trajectory with U-shaped learning patterns.
Initially using correct forms, then overgeneralizing rules (e.g., “goed” instead of “went”), and eventually returning to correct usage after learning exceptions.
Cognitive Mechanisms: Combining domain-specific tools (attention to language) and domain-general cognitive mechanisms (categorisation and memory).
Definition: There is a biologically constrained window (before puberty) during which language acquisition is most efficient.
Impact: If a child is not exposed to a language during this time, full native-like proficiency may be impossible, especially in syntax and phonology.
Evidence:
Case Studies: Genie, who was isolated until age 13, failed to acquire normal grammatical structures.
Late Sign Language Learners: Perform worse on syntactic tasks compared to those exposed from birth.
Neuroscientific Studies: Early language exposure leads to typical lateralisation and activation patterns in language-related brain areas; late learners often show more diffuse or right-hemisphere activation.
Cochlear Implant Studies: Children who receive implants earlier acquire language more effectively.
Conclusion: Brain plasticity for language is time-sensitive, and language input during the critical period is crucial for native-like mastery.
Complexity: More complex than L1 acquisition.
Evidence:
Earlier exposure may lead to more native-like proficiency, especially in pronunciation and grammar.
Johnson and Newport (1989) found a decline in grammatical performance among immigrants learning English after puberty.
Counter-Evidence: Birdsong and Molis (2001) found some adults achieved high levels of grammatical accuracy, suggesting compensation through motivation, input quality, and frequency of use.
Sensitive Period Model: While younger learners have advantages, successful L2 acquisition in adulthood is possible, particularly in immersive environments.
Bilingualism: Experience with multiple languages enhances cognitive flexibility and metalinguistic awareness.
Conclusion: Age interacts with social, psychological, and experiential variables in shaping L2 outcomes.
Models: Levelt, Garrett, Ellis & Young.
Fundamental Stages:
Conceptualisation: Forming a communicative intent.
Lexical Selection: Choosing the appropriate lemma.
Phonological Encoding: Retrieving the lexeme or phonological form.
Articulation: Executing the speech motor plan.
Tip-of-the-Tongue (TOT) States: Speakers retrieve the concept and grammatical properties of a word but fail to access its phonological form.
Neuropsychological and Experimental Evidence: Different types of aphasia illustrate how damage to specific stages results in predictable impairments.
Broca’s aphasia affects syntactic encoding.
Anomia reflects lexical retrieval problems.
Functional Imaging Studies: Distinct activation patterns correspond to each processing stage.
Broca’s Aphasia: Slow, effortful speech with preserved comprehension; indicating damage to regions for grammatical processing and articulation.
Wernicke’s Aphasia: Fluent but semantically incoherent speech; showing deficit in lexical-semantic access.
Anomic Aphasia: Struggle to retrieve specific words despite understanding their meanings; which reinforce independence of semantic and phonological processes.
Split-Brain Studies: Left hemisphere is dominant for language production.
Sperry and Gazzaniga’s studies show patients may name objects presented to the right visual field (processed by the LH) but not the left visual field (processed by the RH).
Conclusion: Naming involves coordinated processes between visual, lexical, and articulatory systems, primarily lateralised to the left hemisphere.
Mechanisms:
Lexical Route: Direct recognition of whole words from the mental lexicon; facilitates reading of irregular words (e.g., “choir,” “colonel”).
Non-Lexical Route: Grapheme-to-phoneme conversion; enables decoding of regular and novel words (e.g., “mint,” “flirp”).
Neuropsychological Evidence:
Surface Dyslexia: Damage to the lexical route results in difficulty reading irregular words, leading to regularisation errors (e.g., reading “pint” to rhyme with “mint”).
Phonological Dyslexia: Damage to the non-lexical route impairs ability to read non-words; familiar words remain accessible via the lexical route.
Functional Imaging Studies: Distinct neural pathways; temporal lobe regions support lexical access, and inferior parietal areas are involved in phonological conversion.
Location: Left fusiform gyrus.
Role: Facilitates rapid recognition of orthographic patterns.
Literate Individuals: Activates robustly during reading tasks, interfacing with phonological and semantic networks.
Illiterate Individuals: Shows reduced or absent activation during reading tasks.
Plasticity: Braille readers show VWFA responsiveness to tactile reading, indicating its tuning to symbolic input relevant to language.
Literacy Training: illiterate adults Leads to measurable increases in VWFA activity.
Conclusion: Reading recruits and repurposes existing brain regions through structured exposure and practice, highlighting that it is not an innate capacity.