Mechanisms of developmental change in infant categorization

Computational models are tools for testing mechanistic theories of learning and development. Formal models allow us to instantiate theories of cognitive development in computer simulations. Model behavior can then be compared to real performance. Connectionist models, loosely based on neural information processing, have been successful in capturing a range of developmental phenomena, in particular on-line within-task category learning by young infants. Here we describe two new models. One demonstrates how age dependent changes in neural receptive field sizes can explain observed changes in on-line category learning between 3 and 10 months of age. The other aims to reconcile two conflicting views of infant categorization by focusing on the different task requirements of preferential looking and manual exploration studies. A dual-memory hypothesis posits that within-task category learning that drives looking time behaviors is based on a fast-learning memory system, whereas categorization based on background experience and assessed by paradigms requiring complex motor behavior relies on a second, slow-learning system. The models demonstrate how emphasizing the mechanistic causes of behaviors leads to discovery of deeper, more explanatory accounts of learning and development.     

Short-term forgetting without interference

In the 1st reported experiment, we demonstrate that auditory memory is robust over extended retention intervals (RIs) when listeners compare the timbre of complex tones, even when active or verbal rehearsal is difficult or impossible. Thus, our tones have an abstract timbre that resists verbal labeling, they differ across trials so that no "standard" comparison stimulus is built up, and the spectral change to be discriminated is very slight and therefore does not shift stimuli across verbal categories. Nonetheless, performance in this nonverbal immediate memory task was better at short (1-, 2-, or 4-s) than long (8-, 16-, or 32-s) RIs, an outcome predicted by temporal distinctiveness theory whereby at long RIs, tones are closer in time to tones on previous trials. We reject this account in the 2nd experiment, where we demonstrate that the ratio of RI to intertrial interval makes absolutely no difference to performance. We suggest that steady forgetting is consistent with a psychoacoustically derived conception of an auditory memory (the timbre memory model) that embodies time-based forgetting in the absence of feature-specific interference.     

Predicting Well-Being From Personality in Adolescents and Older Adults

The relationship between personality and well-being is dynamic and therefore should be examined within aging perspective. In study presented here we compared the prediction of well-being from personality in two samples?C223 adolescents attending high-school (16?C19?years; M?=?16.94, SD?=?0.51) and 134 older adults (54?C90?years; M?=?77.20, SD?=?7.39) living in retirement home or at home. Different aspects of well-being were included in the study. Subjective well-being was measured with Index of Well-Being, but also self-esteem and loneliness were included as measures of psychological well-being. Personality (measured with FFPI; Hendriks et al. in Pers Individ Dif 27:307?C325, 1999) significantly predicted indicators of well-being (Self-Esteem, Loneliness and Index of Well-Being) in both samples, with emotional stability and extraversion as most pronounced predictors. Personality explained more variance of well-being in adolescents than in older adults, and more variance in eudaimonic than hedonic aspects of well-being.     

Biases in evaluation of neutral words due to motor compatibility effect

This study aims to demonstrate the effect of action fluency on emotional evaluation, specifically to show that neutral words can be evaluated positively or negatively depending on motor activity and evaluative setting. Right-handers naturally tend to associate positive (negative) valence to the right (left) part of space (Casasanto, 2009). We extend these associations to lateralized behaviors by studying the combined effect of motor fluency of lateral arm movements and the evaluative scale on the subjective evaluation of neutral words. Three experiments evidenced that, for right-handers, the realization of fluent rightward arm movements and the use of an evaluative scale congruent with their valence/laterality associations (left negative, right positive) led to a positive evaluation of neutral words, while non-fluent leftward movements and an incongruent scale led to a negative evaluation. This study demonstrates that emotion–action associations are experience-based, and influenced by functional and situational constraints.     

Dissociating mental transformations and visuo‐spatial storage in working memory: Evidence from representational neglect

A study is reported of visuo‐spatial working memory in two individuals suffering from a cognitive deficit known as unilateral spatial neglect, and seven healthy control participants. Both patients have difficulties reporting details on the left side of imaged representations, and one has an additional difficulty with perceptual input to the left of his body midline. All participants were asked to report the location and identity of objects presented in novel 2 × 2 arrays that were either present throughout or were described orally by the experimenter, with no visual input. On half of the trials, the report was to be made from the opposite perspective, requiring 180 degree mental rotation of the mentally represented array. The patients show an impaired ability to report details from the presented or the imagined left, but had no difficulty with mental rotation. Results point to a clear separation between the processes of perception and those of visuo‐spatial working memory. Results also suggest that the patients might be suffering from damage to the system used for holding visuo‐spatial representations rather than a difficulty with attending to elements of that representation.     

New insights on eye blindness and hand sight: Temporal constraints of visuo-motor networks

Pioneer experiments on saccadic suppression have shown that this effect is not followed by motor disorientation: Conscious perception of a target displacement can be dissociated from correct manual target reaching. It has subsequently been demonstrated that movement corrections with the same latency and spatial characteristics can be produced in conditions allowing perceptual awareness of perturbation of a target as in condition inducing saccadic suppression. In addition to the qualitative dissociation between motor performance and conscious awareness, quantitative temporal dissociations in action can be observed by manipulating different features of the visual target. When the target of an ongoing simple action is perturbed, a temporal advantage is found for responses to perturbations of location relative to colour and shape. Furthermore, there seems to be a temporal advantage for automatic motor corrections made in response to a target displacement as compared to other responses (other ongoing movement adjustments, movement interruption, conditional motor response such as pressing a key, verbal response, delayed matching-to-sample tasks). Thus, this paper reviews evidence for the fact that the temporal characteristics of any given response to a stimulus are dependent both on the sensory processes and on the type of response generated. Accordingly, identification responses (such as verbal report) to a visual stimulus are much slower than motor corrections of an ongoing movement in response to a target location change because of different processing times of the stimulus features (“What” compared to “Where”) and of the response itself (“What” compared to “How”). The existence of two continua (What/Where and What/How) is proposed between these two extreme stimulus- response combinations. This model may be a useful framework to better understand visuo-motor transformations and the network of connections between visual and motor areas.     

Recognition of complex object-centred spatial configurations in early infancy

In a series of experiments we tested 4- and 8-month-olds’ ability to represent the spatial layout of an object across changes in its orientation with respect to egocentric spatial coordinates. A fixed-trial familiarization procedure based on visual habituation behaviour shows that both age groups are able to discriminate between different object-centred spatial configurations. Furthermore, both age groups demonstrate the ability to make discriminations of object-centred spatial coordinates that require simultaneous reference to at least two spatial axes of the object. We discuss these findings in relation to theories of the early development of object recognition and spatial reference skills.     

Executive Dysfunctions Across Adulthood: Measurement Properties and Correlates of the DEX Self-Report Questionnaire

ABSTRACT

Difficulties in executive processes can disturb daily life functioning. Using data obtained from two independent community-dwelling samples (n ₁?=?468, n ₂?=?669, 18–97 years), we examined the factor structure of the Dysexecutive Functioning Questionnaire (DEX) and explored the frequencies and potential correlates of self-reported executive difficulties. Our results revealed that executive problems are parsimoniously described with one underlying factor. Everyday executive dysfunctions were moderately frequent throughout adulthood. Reports of executive problems were associated with individual difference characteristics including age, subjective health, personality, affect, and cognition. We also found that, although executive functions are known to decline with advancing adult age, younger age groups reported more problems than older groups, an effect that was partially mediated by a negative affect factor. We discuss implications for the validity of the instrument as well as directions for future research on executive functioning difficulties in everyday life.     

Developmental Changes in Response to Frustration among Physically Handicapped Children

Methods of coping with frustration were examined in handicapped and nonhandicapped children at three different age levels, by means of the Rosenzweig P-F Study. While an extrapunitive approach was predominant in both groups and did not differ between the groups, significant differences were found in the use of secondary coping strategies. When compared with nonhandicapped counterparts, handicapped six year olds were more likely to minimize or deny frustration. At 10 years, handicapped Ss were more likely than nonhandicapped Ss to be intropunitive or self-blaming. There was a developmental tendency for handicapped Ss to make greater use of intropunitive responses with increasing age.     

The Relationship of Target and Response Complexity in Coincident Timing Performance

This paper reports two experiments concerned with the interaction of response and target factors in a coincident timing situation. Coincident timing involves executing a response to intercept a moving target. The target response relationship was manipulated in the first experiment by providing some targets with no structure (linear path) and others containing 1 and 2 bounce points. In the second experiment, responses required 0, 1, or 2 reversals in direction. The results provide tentative support for the notion that structure in the target path could be linked to the key temporal response dynamics for improved performance consistency, and that subjects may alter their response structure to incorporate this linkage. This can be further extended to the advantage of simply moving while perceiving movement. This paper stresses the importance of examining the perceptual and motor requirements of the coincident timing skill in unison.