Characterizing perceptual learning with external noise

Performance in perceptual tasks often improves with practice. This effect is known as ‘perceptual learning,’ and it has been the source of a great deal of interest and debate over the course of the last century. Here, we consider the effects of perceptual learning within the context of signal detection theory. According to signal detection theory, the improvements that take place with perceptual learning can be due to increases in internal signal strength or decreases in internal noise. We used a combination of psychophysical techniques (external noise masking and double-pass response consistency) that involve corrupting stimuli with externally added noise to discriminate between the effects of changes in signal and noise as observers learned to identify sets of unfamiliar visual patterns. Although practice reduced thresholds by as much as a factor of 14, internal noise remained virtually fixed throughout training, indicating learning served to predominantly increase the strength of the internal signal. We further examined the specific nature of the changes that took place in signal strength by correlating the externally added noise with observer’s decisions across trials (response classification). This technique allowed us to visualize some of the changes that took place in the linear templates used by the observers as learning occurred, as well as test the predictions of a linear template-matching model. Taken together, the results of our experiments offer important new theoretical constraints on models of perceptual learning.     

Mapping Word to World in ASL: Evidence from a Human Simulation Paradigm

Across languages, children map words to meaning with great efficiency, despite a seemingly unconstrained space of potential mappings. The literature on how children do this is primarily limited to spoken language. This leaves a gap in our understanding of sign language acquisition, because several of the hypothesized mechanisms that children use are visual (e.g., visual attention to the referent), and sign languages are perceived in the visual modality. Here, we used the Human Simulation Paradigm in American Sign Language (ASL) to determine potential cues to word learning. Sign-naïve adult participants viewed video clips of parent–child interactions in ASL, and at a designated point, had to guess what ASL sign the parent produced. Across two studies, we demonstrate that referential clarity in ASL interactions is characterized by access to information about word class and referent presence (for verbs), similarly to spoken language. Unlike spoken language, iconicity is a cue to word meaning in ASL, although this is not always a fruitful cue. We also present evidence that verbs are highlighted well in the input, relative to spoken English. The results shed light on both similarities and differences in the information that learners may have access to in acquiring signed versus spoken languages.     

The social behaviours of inhibited children in and out of preschool

The goal of the present study was to explore the social behaviours of inhibited children in familiar social contexts, including: (1) free play with peers at preschool and (2) social activities at home and in the community. The initial participants were N =248 preschool children between the ages of 42 and 66 months. From this initial data, two smaller groups of inhibited (N =12) and uninhibited comparison (N =12) children were identified. These children were observed during free play at preschool and parents completed daily logs of children's social activities outside of school. Among the findings, inhibited children were observed to display more reticent (on looking, unoccupied) and anxious behaviours during free play preschool than uninhibited children. As well, inhibited children participated less in structured social activities outside school and were more likely to engage in dyadic play at home with a single friend as compared to their uninhibited counterparts.     

Modeling Serial Arguments in Close Relationships: The Serial Argument Process Model

Though an emerging research area, serial argumentation has yet to be cohesively explored from a theoretical lens. The current project thus extends and updates Trapp and Hoff’s (1985) original serial argument model by explicating and testing a theoretical process an individual goes through immediately before, during, and after a serial argument episode. Specifically, perceived resolvability, serial argument goal importance, conflict tactics, rumination, and motivation to achieve goals are examined across romantic and family relationships in the serial argument process model. The proposed paths emerged generally as predicted and the model fit the data. The serial argument process model thus allows for a preliminary theoretical depiction of a serial argument episode enacted in a variety of close relationship contexts.     

Content in Context Improves Deception Detection Accuracy

Past research has shown that people are only slightly better than chance at distinguishing truths from lies. Higher accuracy rates, however, are possible when contextual knowledge is used to judge the veracity of situated message content. The utility of content in context was shown in a series of experiments with students (N = 26, 45, 51, 25, 127) and experts (N = 66). Across studies, average accuracy was 75% in the content in context groups compared with 57% in the controls. These results demonstrate the importance of situating judges within a meaningful context and have important implications for deception theory.