Do Humans Really Learn AnBn Artificial Grammars From Exemplars?

An important topic in the evolution of language is the kinds of grammars that can be computed by humans and other animals. Fitch and Hauser (F&H; 2004) approached this question by assessing the ability of different species to learn 2 grammars, (AB)(n) and A(n) B(n) . A(n) B(n) was taken to indicate a phrase structure grammar, eliciting a center-embedded pattern. (AB)(n) indicates a grammar whose strings entail only local relations between the categories of constituents. F&H's data suggest that humans, but not tamarin monkeys, learn an A(n) B(n) grammar, whereas both learn a simpler (AB)(n) grammar (Fitch & Hauser, 2004). In their experiments, the A constituents were syllables pronounced by a female voice, whereas the B constituents were syllables pronounced by a male voice. This study proposes that what characterizes the A(n) B(n) exemplars is the distributional regularities of the syllables pronounced by either a male or a female rather than the underlying, more abstract patterns. This article replicates F&H's data and reports new controls using either categories similar to those in F&H or less salient ones. This article shows that distributional regularities explain the data better than grammar learning. Indeed, when familiarized with A(n) B(n) exemplars, participants failed to discriminate A(3) B(2) and A(2) B(3) from A(n) B(n) items, missing the crucial feature that the number of As must equal the number of Bs. Therefore, contrary to F&H, this study concludes that no syntactic rules implementing embedded nonadjacent dependencies were learned in these experiments. The difference between human linguistic abilities and the putative precursors in monkeys deserves further exploration.     

Development of visual center of mass localization for grasp point selection

Adults assess precisely the center of mass (CM) of single-bodied objects and choose grasping points that span an axis through or close to the center of mass when lifting them. The present study examined how children and adults assess the CM when lifting two-bodied objects (barbells) and how this ability develops. Four- to five-year olds, 6- to 7-year olds, 9- to 11-year olds and adults were required to grasp and lift symmetrically and asymmetrically proportioned miniature barbells and their grasping points were recorded. While the 4- to 5-year olds grasped near the center of the barbell, accuracy of assessing the correct CM improved linearly with age. Although adults grasped close to the CM, their CM determination follows only an approximation of the physical law.     

The effect of aging on termination of voluntary movement while standing: A study on community-dwelling older adults

For older adults, falls often occur when transitioning from motion to a complete stop, as the motor control required during this phase is very complex and challenging. The purpose of this study was to clarify the effect of aging on the motor control required to terminate motion. Twenty-five healthy older adults (aged >65 years) and 25 healthy young adults (20–23 years) performed a rapid stopping task while standing on a force plate. The rapid stopping task was conducted by analyzing center of pressure (COP) on the force plate during a visually guided tracking experiment. To assess the ability to terminate motion, we measured the velocity waveform for the COP, along with the reaction, propulsion, braking, and total movement times. Both the reaction and movement times of the older-adult group were significantly longer than those of the younger-adult group (all, p < 0.05). There was no significant difference between the groups in regard to the initial backward propulsion time; however, in the subsequent sequence of backward braking, forward propulsion, and backward braking, all times were longer in the older-adult group than in the younger-adult group (p < 0.05). Our results show that the series of time delays shown by older adults when initiating and terminating motion is due to not only delayed reactions but also delayed stopping. Furthermore, our findings suggest that older adults have not only a diminished propulsion ability but also a diminished braking ability.     

Trauma Recovery in the Transgender and Gender Diverse Community: Extensions of the Minority Stress Model for Treatment Planning

Transgender and gender diverse (TGD) populations, including those that do not identify with gender binary constructs (man or woman) are increasingly presenting for treatment of posttrauma sequelae. Providers who offer services for trauma survivors including posttraumatic stress disorder (PTSD) treatment should be knowledgeable about evidence-based care and have some cultural familiarity with TGD experiences. Indeed, the Minority Stress Model suggests that the combination of distal and proximal minority stressors can combine to produce increased mental health symptoms as compared with cisgender peers, though this model has yet to be fully tested. Clients often present with a complicated picture of experiences, which include a variety of minority stressors, microaggressions, discrimination, and traumatic events that can all be related to their identity. However, conceptualizations of trauma treatment in the context of extensive minority stress are lacking. This paper summarizes the existing literature and offers guidance to mental health providers who are well positioned to address stigma, discrimination, violence, and related symptoms that arise from micro-, mezzo- and macro-level spheres of TGD individuals’ experience.     

The effects of distance between interactants and subject anxiety on conjugate lateral eye movements

Ehrlichman and Weinberger (1978, Psychological Bulletin 85, 1080-1101) have suggested that the distance between participants during face-to-face interviewing may be a significant determinant of directional patterns of conjugate lateral eye movements (CLEMS). As predicted, at the longer, social distance CLEMS were dependent on the verbal or spatial nature of questions; when interactants were at a closer, personal distance CLEMS became more consistent in direction, regardless of problem type. Distance manipulation also differentially altered CLEM patterns for the two sexes.     

Computing with connections in visual recognition of origami objects

This paper summarizes our initial foray in tackling Artificial Intelligence problems using a connectionist approach. The particular task chosen was the visual recognition of objects in the Origami world as defined by. The two major questions answered were how to construct a connectionist network to represent and recognize projected line drawings of Origami objects and what advantages such an approach would have. The structure of the resulting connectionist network can be described as a hierarchy of parameter or feature spaces with each node in each of the feature spaces representing a hypothesis about the possible existence of a specific geometric feature of an Origami object. The dynamic behavior of the network is a form of iterative refinement or relaxation whose major characteristic is to prefer more globally interesting interpretations of the input over locally pleasing ones. Examples from the implementation illustrate the system's ability to deal with forms of noise, occlusion and missing information. Other benefits are an inherently parallel approach to vision, limitation of explicit ordering of the search involved in matching model to instance and the elimination of backtracking due to the sharing of partial results as the search progresses. Extensions and problems are also discussed.