Rule- versus instance-based learning in speech-like behavior: An evaluation of transfer and motor class effects

Two information-processing theories of motor control have been postulated for motor learning. Rule-based learning theory predicts transfer when new, untrained stimuli or behaviors share the same set of rules. Instance-based learning theory predicts transfer when new, untrained stimuli are similar in a specific way to the trained stimuli. The purpose of this study was to provide insight into the learning theory operating during nonword acquisition and transfer by evaluating reaction times during an old-new judgment task. Nonword stimuli were constructed to bias familiarity judgments by systematically varying two parameters associated with each theory: phonetic similarity (instance-based) and syllable stress pattern (rule-based). Twenty-four participants (18-35 years of age) with normal hearing and speech production participated in a syllable stress training task and an old-new judgment task. During training, participants articulated a series of nonword stimuli while producing a specific syllable stress pattern. Syllable stress accuracy was monitored by the examiner via perceptual judgments and custom software evaluating acoustic intensity of the articulated stressed syllable. Accurate articulation of nonwords was monitored with recognition probes throughout training. Participants met pre-established accuracy criteria for syllable stress and phonetic production of each experimental nonword. Once criterion was met, participants were assumed to have a highlyaccurate baseline memory representation of the trained items that was judged against a variety of untrained transfer stimuli varying in phonetic similarity and syllable stress pattern. Following training, an old-new judgment task was administered in which participants made familiarity judgments upon hearing a trained or untrained nonword; reaction times were collected via a response box. Reaction time results indicated participants responded faster to untrained nonwords with different phonemes than to untrained nonwords with similar phonemes. Syllable stress pattern did not affect reaction time. These results are consistent with instance-based learning. However, the direction of the similarity effect was in the opposite direction as originally predicted for this theory, i.e., positive transfer occurred when stimuli were dissimilar to one another. Future studies should evaluate what parameters need to be manipulated along a similarity index, and how the variable of dissimilarity may affect overall transfer patterns

Voxel-lesion symptom mapping of coarse coding and suppression deficits in right hemisphere damaged patients

Several accounts of narrative comprehension deficits in adults with right hemisphere damage (RHD) focus on the basic comprehension processes of coarse semantic coding (CC) and suppression (SUP)1,2. CC activates wide-ranging aspects of word meaning, independent of the surrounding context. In RHD, CC deficits impair processing of more remote meanings/features of lexical-semantic representations (e.g., “rotten” as a feature of “apple”)3. The normal SUP process reduces mental activation of concepts that become contextually incompatible. SUP impairment in RHD is indexed by prolonged processing interference from contextually-inappropriate interpretations (e.g., the “ink” meaning of “pen,” in “He built a pen”)4,5. Adults with RHD may have deficits in CC, SUP, both, or neither6. Voxel-based lesion symptom mapping was used to identify right hemisphere (RH) anatomical correlates of CC and SUP deficits. Lesion-deficit correspondence data should help predict which RHD patients have which deficits and may be candidates for a deficit-focused treatment approach that simultaneously improves narrative comprehension7-9. The Bilateral Activation, Integration, and Selection (BAIS) framework of language processing10 suggests some basic hypotheses1. CC, related to the activation component, is hypothesized to involve posterior MTG and STG10,11. SUP, related to the attentionally-driven selection component, modulates lexical-level activation and message-level semantic integration to narrow representations to those most relevant to a comprehender’s goal. Selection is strongly associated with left IFGe.g,12 but RH IFG also is crucial for semantic filtering and selection13,14, especially for information more strongly active in the RH15. Basal ganglia circuits are likely involved, as well13,16

What memory representation is acquired during nonword speech production learning? The influence of stimulus features and training modality on nonword encoding

The purpose of this research was to investigate memory representations related to speech processing. Psycholinguistic and speech motor control theorists have hypothesized a variety of fundamental memory representations, such as syllables or phonemes, which may be learned during speech acquisition tasks. Yet, it remains unclear which fundamental representations are encoded and retrieved during learning and generalization tasks. Two experiments were conducted using a motor learning paradigm to investigate if representations for syllables and phonemes were acquired during a nonword repetition task. Additionally, different training modalities were implemented across studies to examine if training modality influenced memory encoding for nonword stimuli. Results suggest multiple representations may be acquired during training regardless of training modality; however, the underlying memory representations learned during training may be less abstract than current models hypothesize

Right Hemisphere Damage and Theory of Mind Deficit: A Deficit in the Theory?

This study assessed whether right-hemisphere-damaged (RHD) adults’ deficits in processing alternative meanings of lexical ambiguities would extend to semantic feature representations of unambiguous lexical items. If so, RHD deficit was expected to affect only activation/deactivation for subordinate features that are incompatible with the most common representations of unambiguous words (e.g., ‘rotten’ for ‘apple’). Contrary to predictions, neither RHD nor control participants evidenced a change in activation over time for this type of subordinate features. Continued research on RHD adults’ communicative strengths and weaknesses will have future implications for clinical assessment and management

Generalization of a Novel, Implicit Treatment for Coarse Coding Deficit

The language comprehension deficits in adults with focal right hemisphere brain damage (RHD) can cause considerable social handicap. To date, however, treatment for language deficits in this population remains almost entirely untested. This abstract reports a single-subject experimental design study, performed to investigate whether Contextual Constraint Treatment -- a novel, implicit, stimulation-facilitation treatment for language comprehension processes -- can yield generalized gains to broader measures of language comprehension in adults with RHD. The focus of Contextual Constraint Treatment (CCT) is motivated by two major accounts of common language comprehension problems in adults with RHD: coarse coding and suppression deficits. The patient in this study had a coarse coding (CC) deficit, so we describe here only the CC version of the treatment. CC processes activate wide-ranging aspects of word meaning independent of the surrounding context, and CC deficits in adults with RHD impair the processing of distant meanings or features of words (e.g., “rotten” as a feature of “apple”)1. CC is a partially domain-general language comprehension process. That is, CC ability predicts aspects of discourse comprehension, is hypothesized to underpin figurative language comprehension, and is involved in processing phrasal metaphors2. Thus, treatment that improves CC processes has the potential to generalize to a range of communicative outcomes. CCT is novel in aiming to facilitate comprehension processes implicitly, through contextual prestimulation. This approach contrasts with the majority of treatments for neurologically-based cognitive-linguistic disorders, which are direct, explicit, and/or metalinguistic. We implemented this approach to avoid confounding treatment of impaired processes with irrelevant, and potentially difficult, task demands, as adults with RHD who can perform well on implicit assessments of language processing often have difficulty with metalinguistic assessments of the same processing operations2

Implicit Treatment of Underlying Comprehension Processes Improves Narrative Comprehension in Right Hemisphere Brain Damage

Language comprehension deficits in adults with focal right hemisphere brain damage (RHD) can cause considerable social handicap. To date, however, treatment for these deficits remains almost entirely untested. This abstract reports an investigation of whether Contextual Constraint Treatment (CCT) -- a novel, implicit, stimulation-facilitation treatment for language comprehension processes1,2 -- can yield generalized gains to measures of discourse comprehension in adults with RHD. The focus of CCT is motivated by two major accounts of typical RHD language comprehension problems: that they are due to coarse coding or suppression deficits. Coarse coding (CC) activates wide-ranging aspects of word meaning independent of surrounding context. In RHD, CC deficits impair processing of distant meanings/features of words (e.g., “rotten” as a feature of “apple”)3. A normal suppression (SUPP) process reduces mental activation of concepts that become less relevant to a current context. RHD SUPP impairment is indexed by prolonged processing interference from contextually-inappropriate interpretations (e.g., the “ink” meaning of the word “pen,” in the sentence “He built a pen”)4,5. CC and SUPP are partially domain-general language comprehension processes. For example, both predict aspects of discourse comprehension and are hypothesized to underpin figurative language comprehension; SUPP is important for resolving lexical and inferential ambiguities; and CC is involved in processing both literal lexical items and phrasal metaphors1,2,6. Thus, treatment that improves CC and SUPP processes may hold promise for improving a broad range of communicative outcomes. CCT is novel in aiming to facilitate comprehension processes implicitly, through contextual prestimulation. Adults with RHD who perform well on implicit assessments of language processing often have difficulty on metalinguistic assessments of the same operations2. Thus we implemented this approach to avoid confounding treatment of impaired processes with irrelevant, and potentially difficult, task demands

A different story on "Theory of Mind" deficit in adults with right hemisphere brain damage

20 page(s

What memory representation is acquired during nonword speech production learning? The influence of stimulus features and training modality on nonword encoding

The purpose of this research was to investigate memory representations related to speech processing. Psycholinguistic and speech motor control theorists have hypothesized a variety of fundamental memory representations, such as syllables or phonemes, which may be learned during speech acquisition tasks. Yet, it remains unclear which fundamental representations are encoded and retrieved during learning and generalization tasks. Two experiments were conducted using a motor learning paradigm to investigate if representations for syllables and phonemes were acquired during a nonword repetition task. Additionally, different training modalities were implemented across studies to examine if training modality influenced memory encoding for nonword stimuli. Results suggest multiple representations may be acquired during training regardless of training modality; however, the underlying memory representations learned during training may be less abstract than current models hypothesize