Structural constraints in the perception of English stop-sonorant clusters

Native-language phonemes combined in a non-native way can be misperceived so as to conform to native phonotactics, e.g. English listeners are biased to hear syllable-initial [tr] rather than the illegal [tl] (Perception and Psychophysics 34 (1983) 338; Perception and Psychophysics 60 (1998) 941). What sort of linguistic knowledge causes phonotactic perceptual bias? Two classes of models were compared: unit models, which attribute bias to the listener's differing experience of each cluster (such as their different frequencies), and structure models, which use abstract phonological generalizations (such as a ban on [coronal][coronal] sequences). Listeners (N=16 in each experiment) judged synthetic 6 x 6 arrays of stop-sonorant clusters in which both consonants were ambiguous. The effect of the stop judgment on the log odds ratio of the sonorant judgment was assessed separately for each stimulus token to provide a stimulus-independent measure of bias. Experiment 1 compared perceptual bias against the onsets [bw] and [dl], which violate different structural constraints but are both of zero frequency. Experiment 2 compared bias against [dl] in CCV and VCCV contexts, to investigate the interaction of syllabification with segmentism and to rule out a compensation-for-coarticulation account of Experiment 1. Results of both experiments favor the structure models (supported by NSF).     

Do Positive Self-Perceptions Have a “Dark Side”? Examination of the Link between Perceptual Bias and Aggression

The hypothesis that positive self-perceptions may have a dark side was investigated in the present study by examining the relationship between positively biased self-perceptions and aggression. Ratings of actual and perceived social acceptance of third-grade (n = 278), fourth-grade (n = 260), and fifth-grade (n = 321) students were compared to form a measure of perceptual bias. Peers provided nominations for overt and relational aggression. Gender differences were found for aggression (males were more overtly and relationally aggressive than females) but not perceptual bias. African-American children held more positive perceptions of their social acceptance and were perceived by peers as more aggressive than Caucasian children. Even after controlling for the effects of gender and ethnicity, more positively biased perceptions were associated with more peer nominations for overt and relational aggression. Contrary to an optimal range of bias hypothesis, even moderately positive self-perceptions were associated with elevated levels of aggression.     

Generalizability of carry-over effects in the emotional Stroop task

The emotional Stroop task has been the most widely used task to examine attentional bias to emotionally salient stimuli. In one format of this task, words are presented to participants in a mixed randomized or quasi-randomized sequence. Using a mixed smoking Stroop task, we have previously demonstrated that smokers are slower to respond to words which follow smoking-related words than words which follow neutral words. Here we show that this carry-over effect is present in heroin addicts-but not control subjects-in a heroin Stroop task, and in normal subjects in a stress Stroop task. Thus, the effect generalizes to other populations. In addition, an examination of the studies that have collected data from both mixed and blocked formats provides converging evidence for the presence of carry-over effects. We discuss the implications of the carry-over effect for research using the emotional Stroop task.     

Concurrent second-order schedules: some effects of variations in response number and duration

To examine the effects on concurrent performance of independent manipulations of response-unit duration and number, 6 hens were exposed to concurrent second-order schedules of reinforcement. Each first-order operant unit required completion of a fixed-ratio schedule within the time specified by a fixed-interval schedule, with one further response completing the fixed-interval schedule. The fixed-ratio and fixed-interval requirements comprising the first-order operant units were systematically and independently varied under three pairs of concurrent variable-interval schedules to produce differences in the first-order response and duration requirements (response and duration differentials). These manipulations produced consistent changes in response, time, and operant-unit biases. A 1:4 response differential biased the time and operant-unit measures towards the smaller fixed ratio, but to a degree less than the imposed response differential. The response-based biases favored the larger fixed ratio. Duration differentials of 4:1 and 8:1 biased the response and operant-unit measures towards the shorter fixed interval, again less than the imposed duration differential, but the time biases remained close to zero. Both sorts of differentials acted to bias operant-unit completions more systematically than the other measures, but undermatching to the differentials occurred. The undermatching appears to have arisen from a pattern of fix and sample (in which visits to the less preferred alternative involved only a single completed operant unit) under combinations of unequal operant-unit requirements and reinforcer rates. The response and time bias measures appeared to arise as by-products of the changes in operant-unit completions.     

The Impact of the Big Five Personality Traits on Reports of Child Behavior Problems by Different Informants

The present study compared ratings of a standardized sample of child behavior problems across informants and examined the effects of informant personality traits on child behavior ratings by mothers, teachers, and group-care workers. Participants were 55 clinic-referred children, aged 6–12 years. All informants watched and rated the same 17-min videotaped behavior sample of a familiar target child. Independent trained observers rated the same videotapes to provide criterion ratings. Informants personality traits were assessed using the NEO Five Factor Personality Inventory. Results showed that mothers reported fewer behavior problems than did the professionals, that the informants who were familiar with the child reported more behavior problems than did the independent observers, and that higher levels of informant neuroticism were related to higher ratings of child behavior problems in the case of the professionals, but not in the case of the mothers. In addition, group-care workers who were less extraverted and open were likely to report more child behavior problems than group-care workers with normal levels of extraversion and openness. Finally, no relations were found between agreeableness or conscientiousness and ratings of child behavior. Findings suggest that professionals who work with children are not immune to distortions based on their own personality.     

Speech and non-speech processing in people with specific language impairment: a behavioural and electrophysiological study

McArthur and Bishop (2004) found that people with specific language impairment (SLI) up to 14 years of age have poor behavioural frequency discrimination (FD) thresholds for 25-ms pure tones, while people with SLI upto 20 years of age have abnormal auditory N1--P2--N2 event-related potential (ERP) responses to the same tones. In the present study, we extended these findings to more complex non-speech and speech sounds by comparing younger (around 13 years) and older (around 17 years) teenagers with SLI and controls for their behavioural FD thresholds and N1-P2 ERPs to 25 and 250-ms pure tones, vowels, and non-harmonic complex tones. We found that a subgroup of people with SLI had abnormal responses to tones and vowels at the level of behaviour and the brain, and that poor processing was associated with the spectral complexity of auditory stimuli rather than their phonetic significance. We suggest that both the age of listeners and the sensitivity of psychoacoustic tasks to age-related changes in auditory skills may be crucial factors in studies of sound processing in SLI.     

Expectancies for Sexually Abused Children: Evidence of Perceiver Bias

We investigated perceiver bias in relation to children labeled as sexually abused. Building on recent research indicating that adults perceive children with such a label as having more behavioral problems and lower achievement, we replicated and expanded upon an earlier study. We tested undergraduate students (N = 699), who judged a six-year old child's aggressive behavior in vignettes that varied on severity of the aggressive behavior, child gender, and family history (sexually abused, mother dying of cancer, normal). Perceiver bias was related to family history label for internalizing behavior problems and competence issues and child gender for internalizing behavior problems and externalizing behavior problems. Implications for educators and practitioners are discussed as well as routes for future research.     

Neighbourhood effects on error rates in speech production

Models of speech production differ on whether phonological neighbourhoods should affect processing, and on whether effects should be facilitatory or inhibitory. Inhibitory effects of large neighbourhoods have been argued to underlie apparent anti-frequency effects, whereby high-frequency default features are more prone to mispronunciation errors than low-frequency nondefault features. Data from the original SLIPs experiments that found apparent anti-frequency effects are analysed for neighbourhood effects. Effects are facilitatory: errors are significantly less likely for words with large numbers of neighbours that share the characteristic that is being primed for error ("friends"). Words in the neighbourhood that do not share the target characteristic ("enemies") have little effect on error rates. Neighbourhood effects do not underlie the apparent anti-frequency effects. Implications for models of speech production are discussed.