Meredith McKague

A behavioral database for masked form priming

Reading involves a process of matching an orthographic input with stored representations in lexical memory. The masked priming paradigm has become a standard tool for investigating this process. Use of existing results from this paradigm can be limited by the precision of the data and the need for cross-experiment comparisons that lack normal experimental controls. Here, we present a single, large, high-precision, multicondition experiment to address these problems. Over 1,000 participants from 14 sites responded to 840 trials involving 28 different types of orthographically related primes (e.g., castfe–CASTLE) in a lexical decision task, as well as completing measures of spelling and vocabulary. The data were indeed highly sensitive to differences between conditions: After correction for multiple comparisons, prime type condition differences of 2.90 ms and above reached significance at the 5% level. This article presents the method of data collection and preliminary findings from these data, which included replications of the most widely agreed-upon differences between prime types, further evidence for systematic individual differences in susceptibility to priming, and new evidence regarding lexical properties associated with a target word’s susceptibility to priming. These analyses will form a basis for the use of these data in quantitative model fitting and evaluation and for future exploration of these data that will inform and motivate new experiments.

The locus of impairment in English developmental letter position dyslexia

Many children with reading difficulties display phonological deficits and struggle to acquire non-lexical reading skills. However, not all children with reading difficulties have these problems, such as children with selective letter position dyslexia (LPD), who make excessive migration errors (such as reading slime as “smile”). Previous research has explored three possible loci for the deficit – the phonological output buffer, the orthographic input lexicon, and the orthographic-visual analysis stage of reading. While there is compelling evidence against a phonological output buffer and orthographic input lexicon deficit account of English LPD, the evidence in support of an orthographic-visual analysis deficit is currently limited. In this multiple single-case study with three English-speaking children with developmental LPD, we aimed to both replicate and extend previous findings regarding the locus of impairment in English LPD. First, we ruled out a phonological output buffer and an orthographic input lexicon deficit by administering tasks that directly assess phonological processing and lexical guessing. We then went on to directly assess whether or not children with LPD have an orthographic-visual analysis deficit by modifying two tasks that have previously been used to localize processing at this level: a same-different decision task and a non-word reading task. The results from these tasks indicate that LPD is most likely caused by a deficit specific to the coding of letter positions at the orthographic-visual analysis stage of reading. These findings provide further evidence for the heterogeneity of dyslexia and its underlying causes.

Source monitoring and proneness to auditory-verbal hallucinations: A signal detection analysis

Introduction. It has been suggested that a bias to misattribute self-generated thoughts to a nonself source underlies the experience of auditory-verbal hallucinations (AVH). We tested this hypothesis with healthy participants prone or not prone to AVH. Method. Participants (N=133) were presented with 96 words for subsequent recognition (half positively, half negatively valenced). For self-generated trials, participants generated a sentence containing the word. For other-generated trials, participants heard a prerecorded sentence containing the word. At test, studied words were re-presented visually, intermixed with 96 matched lures. Participants indicated the study status (old or new) and source (self or other) for each item. Sensitivity and bias measures were derived for item and source memory using signal detection theory. The 20 participants scoring highest on questions relating to AVH from the revised Launay-Slade Hallucination Scale formed the high-AVH group and the 20 scoring lowest formed the low-AVH group. Results. ANOVAs revealed no significant differences between the two participant groups in sensitivity or bias of source memory, regardless of item valence. There was a trend for the sensitivity of item memory to be lower in the high-AVH group, compared with the low-AVH group. The bias of item memory was not significantly different between groups. Conclusions. Although we found no evidence that source-monitoring problems underlie the experience of AVHs in the general population, we recommend that signal detection measures be applied in future investigations of source monitoring in at-risk and clinical populations.

Disentangling the developmental trajectories of letter position and letter identity coding using masked priming

Masked transposed-letter (TL) priming effects have been used to index letter position processing over the course of reading development. Whereas some studies have reported an increase in TL priming over development, others have reported a decrease. These findings have led to the development of 2 somewhat contradictory accounts of letter position development: the lexical tuning hypothesis and the multiple-route model. One factor that may be contributing to these discrepancies is the use of baseline primes that substitute letters in the target word, which may confound the effect of changes in letter position processing over development with those of letter identity. The present study included an identity prime (e.g., listen—LISTEN), in addition to the standard two-substituted-letter (2SL; e.g., lidfen—LISTEN) and all-letter-different (ALD; e.g., rodfup—LISTEN) baselines, to remove the potential confound between letter position and letter identity information in determining the effect of the TL prime. Priming effects were measured in a lexical decision task administered to children aged 7–12 and a group of university students. Using inverse transformed response times, targets preceded by a TL prime were responded to significantly faster than those preceded by 2SL and ALD primes, and priming remained stable across development. In contrast, targets preceded by a TL prime were responded to significantly slower than those preceded by an ID prime, and this reaction-time cost increased significantly over development, with adults showing the largest cost. These findings are consistent with a lexical tuning account of letter position development, and are inconsistent with the multiple-route model.

Hearing voices inside and outside the head: spatial source monitoring in participants prone to auditory hallucinations.

Introduction. Previous studies of source monitoring and auditory hallucinations (AH) have often conflated spatial source (internal-external) with source agency (self–other). Other studies have used suboptimal manipulations of auditory space (e.g., imagine saying vs. saying aloud). We avoided these problems by presenting experimenter-generated stimuli over headphones in the voice of another person so that the location of the voice sounded either internal or external to the participants head. Methods. Participants (N=121) studied 96 words and indicated for each whether it was presented internally or externally (online spatial source monitoring). At test, studied words were presented visually, intermixed randomly with 96 unstudied words. Participants indicated whether each item was old or new (item memory) and whether it was presented internally or externally during study (spatial source memory). Independent measures of memory accuracy and response bias were derived for online source monitoring, item memory and source memory using signal detection theory. Performance on these measures was compared between two groups of 30 participants who scored low or high on a measure of AH proneness. Results. ANOVAs revealed no differences between the high- and low-AH groups in online spatial source monitoring, item memory, or spatial source memory. Conclusions. We found no evidence that proneness to AH in a sample of healthy volunteers was related to any of the measures of spatial source monitoring performance. We recommend that the methods introduced be applied to future investigations of spatial source monitoring with patient groups and with individuals at-risk for psychosis.

PeerWise: evaluating the effectiveness of a web-based learning aid in a second-year psychology subject

Testing can do more than just determine what a student knows; it can aid the learning process, a phenomenon known as the testing effect. There is a growing trend for students to create and share self-assessment questions in their subject, as advocated by the contributing-student pedagogy (CSP). For subjects with large enrolments, this process can be facilitated by educational technology. PeerWise is an example of such technology. It is free, web-based software that allows students to author, share, answer, and provide feedback on multiple-choice quizzes in a collaborative and constructivist fashion. While it is popular, it is unclear to what degree it facilitates student learning. To evaluate its effectiveness, we introduced PeerWise into a second-year psychology subject. We measured the extent to which it increased scores in the final exam. We found that PeerWise did significantly increase exam scores, so was a useful learning aid.

A comparison of the effectiveness of two computer-based learning aids

Instructors are increasingly using computer-based educational technologies to augment their courses. As answering quizzes has been shown to be one of the most effective learning strategies, a growing number of computer-based learning aids use quizzing. So which of these learning aids should instructors recommend to their students? These learning aids typically either present the student with a number of potential answers and require that they recognize the correct answer (i.e., a multiple-choice quiz) or else they might require the student to recall the answer without assistance (i.e., a free recall quiz). Numerous lab-based studies have shown that recall-based quizzes promote more learning and result in higher performance in a subsequent exam/test than recognition-based quizzes. In the present study, we investigated to what extent this finding holds in an actual university setting with two commercially-available learning aids. We found that while both types of learning aid proved to be effective, we could find no evidence that the recall-based learning aid was more effective than the recognition-based learning aid. In light of this, we discuss possible reasons why the laboratory findings did not readily translate to an actual university setting and make practical recommendations for what sort of computer-based learning aid instructors should incorporate into their university courses.