Infants' understanding of object-directed action

When and in what ways do infants recognize humans as intentional actors? An important aspect of this larger question concerns when infants recognize specific human actions (e.g. a reach) as object-directed (i.e. as acting toward goal-objects). In two studies using a visual habituation technique, 12-month-old infants were tested to assess their recognition that an adult's reach is directed toward its target object. Infants in the experimental condition were habituated to a display in which an actor reached over a wall-like barrier with an arcing arm movement, to pick up a ball. After habituation infants saw two test displays, for which the barrier was removed. In the direct test event the actor reached directly for the ball, the arm tracing a visually new path, but the action consistent with attempting to reach for the object as directly as possible. In the indirect test event the actor traced the old path, reaching over in an arc, even though the wall was no longer present. This arm movement was identical to that in habituation but no longer displayed a reach going directly to its object. In a control condition infants saw the same movements but in a situation with no goal-object. In the experimental conditions, with a goal object present, infants looked longer at the indirect test event in comparison to the direct test event. In the control conditions infants looked equally at both indirect and direct test events. We conclude that sensitivity to human object-directed action is established by 12-month-olds and compare these results to recent findings by [Gergely, G., Nadasdy, Z., Csibra, G., & Biro S. (1995). Taking the intentional stance at 12 months of age. Cognition, 56, 165-193] and [Woodward, A. (1998). Infants selectively encode the goal object of an actor's reach. Cognition, 69, 1-34].     

Do People Know How Their Personality Has Changed? Correlates of Perceived and Actual Personality Change in Young Adulthood

Abstract How much do we think our personality changes over time? How well do our perceptions of change correspond with actual personality change? Two hundred and ninety students completed measures of the Big Five personality traits when they first entered college. Four years later, they completed the same measures and rated the degree to which they believed they had changed on each dimension. Participants tended to view themselves as having changed substantially, and perceptions of change showed some correspondence with actual personality change. Perceived and actual change showed theoretically meaningful correlations with a host of variables related to different aspects of college achievement and adjustment.     

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.     

A case study of mediated learning, delayed auditory feedback, and motor repatterning to reduce stuttering

A case study of DW, an 11-yr. old monolingual, English-speaking boy who exhibits stuttering, language delay, and ADHD is presented. DW experienced only limited improvement during stuttering therapy received in public schools, according to parents and the public school clinician. The purpose of this case study was to assess whether fluency treatment which incorporated Mediated Learning, Delayed Auditory Feedback, and Speech Motor Repatterning would enhance progress. Therapy was delivered in two treatments, with each treatment being 5 wk. of intense therapy, separated by one year. Treatment 1 of combined Mediated Learning and Delayed Auditory Feedback yielded improvement in fluency, judged by parents and the teacher to be clinically significant. The improved fluency was maintained for one year when DW was pretested for participation in Treatment 2, which combined Mediated Learning, Delayed Auditory Feedback, and Speech Motor Repatterning Exercises. As no conclusions are possible, further study is needed.     

Working memory and intelligence: the same or different constructs?

Several investigators have claimed over the past decade that working memory (WM) and general intelligence (g) are identical, or nearly identical, constructs, from an individual-differences perspective. Although memory measures are commonly included in intelligence tests, and memory abilities are included in theories of intelligence, the identity between WM and intelligence has not been evaluated comprehensively. The authors conducted a meta-analysis of 86 samples that relate WM to intelligence. The average correlation between true-score estimates of WM and g is substantially less than unity (p=.479). The authors also focus on the distinction between short-term memory and WM with respect to intelligence with a supplemental meta-analysis. The authors discuss how consideration of psychometric and theoretical perspectives better informs the discussion of WM-intelligence relations.     

Meaning through syntax is insufficient to explain comprehension of sentences with reduced relative clauses: comment on McKoon and Ratcliff (2003)

The authors argue that the meaning through syntax (MTS) model proposed by G. McKoon and R. Ratcliff fails to account for the comprehension of sentences with reduced relative clauses. First, the theory's core assumptions regarding verb-based event representations and how they link to constructions are incompatible with well-established analyses from the lexical semantics literature. Second, the MTS theory provides neither a principled nor a consistent account for why some reduced relatives are hard whereas others are easy. Finally, McKoon and Ratcliff's critique of constraint-based models is flawed in that sometimes they tested a nonexistent theory and sometimes they provided evidence for the constraint-based models against which they were arguing.     

The locus of semantic priming in RSVP target search

At what stage does semantic priming affect accuracy in target search? In two experiments, participants viewed two streams of stimuli, each including a target word among distractors. Stimulus onset asynchronies (SOAs) between the targets (T1 and T2) ranged from 53 to 213 msec. A word semantically related to one or neither of the targets preceded each trial. In Experiment 1, participants were instructed to report both targets. Although more primed than unprimed targets were reported, there was no cost for unprimed words. A strong interaction between SOA and T1 versus T2 was found, but priming did not interact with either variable. In Experiment 2, only related targets were reported. Performance was similar to that for primed targets in Experiment 1. Semantic priming does not seem to modulate how attentional resources are initially allocated between targets, but instead affects a later stage of processing, the point at which a target word reaches lexical identification.     

Final part-word repetitions in school-age children: two case studies

In contrast to the many published accounts of the disfluent repetition of sounds at the beginnings of words, cases where it is predominantly the final parts of words that are repeated have been reported relatively rarely. With few exceptions, those studies that have been published have described either pre-school children or neurologically impaired subjects. The purpose of this case report was to describe final part-word repetitions in the speech of two school-age boys of normal intelligence with no known neurological lesions. Their speech was recorded during spontaneous conversation, reading, and sentence repetition. The repetitions occurred in all three speaking conditions, although the majority of instances were observed in spontaneous speech, and on both content words and function words. The participants exhibited no apparent awareness of the disfluencies, no abnormal muscle tension, and no accessory behaviours. Each child produced word-final repeated fragments whose phonological structure was highly predictable according to his individual set of rules. The results are discussed in terms of possible motor and cognitive explanations for the disfluencies. EDUCATIONAL OBJECTIVES: As a result of this activity, the participant will be able to: (1) summarize prior research into final part-word repetition; (2) describe the detailed characteristics of final part-word repetitions as displayed by two children of normal intelligence; and (3) discuss ways in which the behaviour might be explained as part of a model of speech production.