The formation of a generalized categorization repertoire: effect of training with multiple domains,samples, and comparisons

The present experiment explored the effects of three variables on the spontaneous categorization of stimuli in perceptually distinct and novel domains. Each of six stimulus domains was created by morphing two images that were the domain endpoints. The endpoints of the domains were male and female faces, two abstract drawings, a car and a truck, two banded-elevation satellite land images, a tree and a cat, and two false-color satellite images. The stimulus variants at each end of a domain defined two potential perceptual classes. Training was conducted in a matching-to-sample format and used stimuli from one or two domains, one or three variants per class as samples, and one or three variants per class as comparisons. The spontaneous categorization of stimuli in the untrained stimulus domains showed the emergence of a generalized categorization repertoire. The proportion of spontaneously categorized stimuli in the new domains was positively related to the number of domains and samples used in training, and was inversely related to the number of comparisons used in training. Differential reaction times demonstrated the discriminability of the stimuli in the emergent classes. This study is among the first to provide an empirical basis for a behavior-analytic model of the development of generalized categorization repertoires in natural settings.     

Exposure,Loss, and Support Predicting the Dimensions of Posttsunami Trauma

This study examined whether exposure, resource loss, and social support predicted the posttsunami trauma of PTSD, depression, negative affect, and physical health problems of the 2004 tsunami survivors. Four hundred sixteen survivors were interviewed in Tamil Nadu (India) 14 months posttsunami. Loss of life followed by loss of property and disaster exposure positively predicted the dimensions of trauma. Survivors having lower social status and income received less material and informational support than their equally affected counterparts, which furthered stress and distress. The survivors’ trauma can be arrested, minimizing the exposure and tangible resource loss, and improving the delivery of social support.     

Attachment Styles Predicting Posttsunami Trauma: The Mediating Effects of Coping

This study examined whether tsunami survivors’ coping styles mediate the effects of attachment styles on posttsunami trauma. Four hundred and sixteen survivors were interviewed from Tamil Nadu (India) 14 months posttsunami. Attachment style, coping, and posttsunami trauma were assessed using inventories, and exposure was assessed using a checklist. The female and the more exposed survivors experienced more posttsunami trauma. After controlling the effects of disaster exposure and gender, high fearfully attached persons had more trauma, used more problem-focused coping, and less active and avoidant emotional coping. High dismissively attached persons had less trauma, used less problem-focused coping, and more active and avoidant emotional coping. Attachment styles are related to trauma and coping styles, but indirect effects of attachment styles via coping styles do not predict posttsunami trauma.     

The Role of Strategy in Mixed-Gender Group Interactions: A Study of the Television Show “The Weakest Link”

This paper studies mixed-gender group interactions in a strategic game where group members are sequentially eliminated till a single winner takes all. Study 1 tests the hypothesis that female contestants are retained till final rounds where they are eliminated. Using observational data from the US television show The Weakest Link (20 shows), results show that females are finalists but not winners. In a laboratory study (Study 2, 67 Berkeley undergraduates), we show that this effect is attenuated when winnings are shared among finalists (versus one winner takes all) due to the reduction in competitive pressures in the context. This research was supported in part by the Junior Faculty Research Grant awarded by the University of California at Berkeley to the second author.     

Syntactic priming in 3- and 4-year-old children: evidence for abstract representations of transitive and dative forms

The current studies used a syntactic priming paradigm with 3- and 4-year-old children. In Experiment 1, children were asked to describe a series of drawings depicting transitive and dative relations to establish baseline production levels. In Experiment 2, an experimenter described a similar series of drawings using one of two syntactic forms (i.e., active/passive for transitive; double-object/prepositional for dative). Children were then asked to describe pictures identical to those shown in the corresponding baseline procedure. In both transitive and dative conditions, 4-year-old children were more likely to use a particular syntactic form if it had been used by the experimenter. Three-year-old children did not show priming effects, but their production of transitive sentences was higher following transitive primes than in Experiment 1. In Experiment 3, an additional group of 3-year-olds participated in a procedure in which they repeated the experimenter's sentences before describing the pictures. This procedure yielded significant priming effects for transitive and dative forms. These results indicate that very young children possess abstract syntactic representations, but that their access to these representations is sensitive to task demands.     

The effect of line configuration on perceived numerosity of dotted lines

Estimates of the number of objects in a line are made in many different situations. This paper demonstrates that besides the actual number of dots, aspects of line configuration affect the perceived numerosity of dotted lines. Experiment 1 provides evidence that the highly studied “clutter effect” in distance perception research replicates to the numerosity domain so that lines made up of more segments are perceived to contain more dots. Experiments 2–5 provide nomological validity for the recently proposed “direct distance” effect in distance perceptions by showing that numerosity perceptions are higher the greater the euclidean length between the line end points and by manipulating euclidean length in three orthogonal ways: the relative length of segments (Experiment 2), the angle between segments (Experiment 3), and the general direction of segments (Experiment 4). Experiment 5 conceptually replicates the results of Experiments 2–4 utilizing stimuli-based versus memory-based judgments and a discrimination task. Experiments 6 and 7 extend the research on spatial perception by demonstrating that the use of euclidean length as a source of information is inversely related to line width, with width varied through clutter (Experiment 6) and total line length (Experiment 7). Overall, the results demonstrate that the robustness of the euclidean length effect is contingent on the salience of alternative spatial heuristics-specifically, euclidean width. Theoretical implications are discussed.     

The formation of linked perceptual classes

Multiple-exemplar training with stimuli in four domains induced two new fill-based (A1' and A2') and satellite-image-based (B1' and B2') perceptual classes. Conditional discriminations were established between the endpoints of the A1' and B1' classes as well as the A2' and B2' classes. The emergence of linked perceptual classes was evaluated by the performances occasioned by nine cross-class probes that contained fill variants as samples and satellite variants as comparisons, along with nine other cross-class probes that consisted of satellite variants as samples and fill variants as comparisons. The 18 probes were first presented serially and then concurrently. Class-consistent responding indicated the emergence of linked perceptual classes. Of the linked perceptual classes, 70% emerged during the initial serial test. An additional 20% of the linked perceptual classes emerged during the subsequently presented concurrent test block. Thus, linked perceptual classes emerged on an immediate or delayed basis. Linked perceptual classes, then, share structural and fuctional similarities with equivalence classes, generalized equivalence classes, cross-modal classes, and complex maturally occurring categories, and may clarify processes such as intersensory perception.