Speaker- versus listener-oriented disfluency: A re-examination of arguments and assumptions from autism spectrum disorder

We re-evaluate conclusions about disfluency production in high-functioning forms of autism spectrum disorder (HFA). Previous studies examined individuals with HFA to address a theoretical question regarding speaker- and listener-oriented disfluencies. Individuals with HFA tend to be self-centric and have poor pragmatic language skills, and should be less likely to produce listener-oriented disfluency. However, previous studies did not account for individual differences variables that affect disfluency. We show that both matched and unmatched controls produce fewer repairs than individuals with HFA. For silent pauses, there was no difference between matched controls and HFA, but both groups produced more than unmatched controls. These results identify limitations in prior research and shed light on the relationship between autism spectrum disorders and disfluent speech

Social Transmission of Avoidance Behavior under Situational Change in Learned and Unlearned Rats

BACKGROUND: Rats receive information from other conspecifics by observation or other types of social interaction. Such social interaction may contribute to the effective adaptation to changes of environment such as situational switching. Learning to avoid dangerous places or objects rapidly occurs with even a single conditioning session, and the conditioned memory tends to be sustained over long periods. The avoidance is important for adaptation, but the details of the conditions under which the social transmission of avoidance is formed are unknown. We demonstrate that the previous experience of avoidance learning is important for the formation of behaviors for social transmission of avoidance and that the experienced rats adapt to a change of situation determined by the presence or absence of aversive stimuli. We systematically investigated social influence on avoidance behavior using a passive avoidance test in a light/dark two-compartment apparatus. METHODOLOGY/PRINCIPAL FINDINGS: Rats were divided into two groups, one receiving foot shocks and another with no aversive experience in a dark compartment. Experienced and inexperienced rats were further divided into subjects and partners. In Experiment 1, each subject experienced (1) interaction with an experienced partner, (2) interaction with an inexperienced partner, or (3) no interaction. In Experiment 2, each subject experienced interaction with a partner that received a shock. The entering latency to a light compartment was measured. The avoidance behavior of experienced rats was inhibited by interaction with inexperienced or experienced partners in a safely-changed situation. The avoidance of experienced rats was reinstated in a dangerously-changed situation by interaction with shocked rats. In contrast, the inexperienced rats were not affected by any social circumstances. CONCLUSIONS/SIGNIFICANCE: These results suggest that transmitted information among rats can be updated under a situational change and that the previous experience is crucial for social enhancement and inhibition of avoidance behavior in rats

Experimental evidence for action imitation in killer whales (Orcinus orca)

Comparative experimental studies of imitative learning have focused mainly on primates and birds. However, cetaceans are promising candidates to display imitative learning as they have evolved in socioecological settings that have selected for large brains, complex sociality, and coordinated predatory tactics. Here we tested imitative learning in killer whales, Orcinus orca. We used a 'do-as-other-does' paradigm in which 3 subjects witnessed a conspecific demonstrator's performance that included 15 familiar and 4 novel behaviours. The three subjects (1) learned the copy command signal 'Do that' very quickly, that is, 20 trials on average; (2) copied 100 % of the demonstrator's familiar and novel actions; (3) achieved full matches in the first attempt for 8-13 familiar behaviours (out of 15) and for the 2 novel behaviours (out of 2) in one subject; and (4) took no longer than 8 trials to accurately copy any familiar behaviour, and no longer than 16 trials to copy any novel behaviour. This study provides experimental evidence for body imitation, including production imitation, in killer whales that is comparable to that observed in dolphins tested under similar conditions. These findings suggest that imitative learning may underpin some of the group-specific traditions reported in killer whales in the field.</p