Steve Joordens

Long-Term Semantic Priming: A Computational Account and Empirical Evidence

Semantic priming is traditionally viewed as an effect that rapidly decays. A new view of long-term word priming in attractor neural networks is proposed. The model predicts long-term semantic priming under certain conditions. That is, the task must engage semantic-level processing to a sufficient degree. The predictions were confirmed in computer simulations and in 3 experiments. Experiment 1 showed that when target words are each preceded by multiple semantically related primes, there is long-lag priming on a semantic-decision task but not on a lexical-decision task. Experiment 2 replicated the long-term semantic priming effect for semantic decisions with only one prime per target. Experiment 3 demonstrated semantic priming with much longer word lists at lags of 0, 4, and 8 items. These are the first experiments to demonstrate a semantic priming effect spanning many intervening items and lasting much longer than a few seconds.

Recollection and familiarity through the looking glass: when old does not mirror new.

The authors use the qualitative differences logic to demonstrate that 2 separate memory influences underlie performance in recognition memory tasks, familiarity and recollection. The experiments focus on the mirror effect, the finding that more memorable stimulus classes produce higher hit rates but lower false-alarm rates than less memorable stimulus classes. The authors demonstrate across a number of experiments that manipulations assumed to decrease recollection eliminate or even reverse the hit-rate portion of the mirror effect while leaving the false-alarm portion intact. This occurs whether the critical distinction between conditions is created during the test phase or manipulated during the study phase. Thus, when recollection is present, it dominates familiarity so that the hit-rate portion of the mirror effect primarily reflects recollection; when recollection is largely absent, the opposite pattern associated with the familiarity process emerges.

Assessing the effectiveness of a voluntary online discussion forum on improving students' course performance

The purpose of this study was to evaluate the effectiveness of voluntary discussion forums in a higher education setting. Specifically, we examined intrinsic forum participation and investigated its relation to course performance across two experiments. In Experiment 1 (N = 1284) an online discussion forum was implemented at the beginning of an undergraduate introductory psychology course, and measures of course performance (i.e., writing assignment grades, exam grades, and extra-credits obtained) were compared with measures of forum participation. In Experiment 2 (N = 1334) an online discussion forum was implemented halfway through a second undergraduate introductory psychology course, after an initial measure of course performance was obtained, to control for the potential confound of student engagement (e.g., students who perform better in the course use the forum more). Overall, the results showed that students who participated in the forum tended to have better performance in the course, and furthermore that participating in the discussion forum, particularly reading posts on the forum, slightly improved exam performance. This study provides empirical support for the theoretical proposition that there is a facilitation effect of discussion forum participation on course performance. The results also suggest that implementation of an online discussion forum is beneficial even if a teacher only invests minimal time on the forum.

Investigating a memory-based account of negative priming: support for selection-feature mismatch.

Using typical and modified negative priming tasks, the selection-feature mismatch account of negative priming was tested. In the modified task, participants performed selections on the basis of a semantic feature (e.g., referent size). This procedure has been shown to enhance negative priming (P. A. MacDonald, S. Joordens, & K. N. Seergobin, 1999). Across 3 experiments, negative priming occurred only when the repeated item mismatched in terms of the feature used as the basis for selections. When the repeated item was congruent on the selection feature across the prime and probe displays, positive priming arose. This pattern of results appeared in both the ignored- and the attended-repetition conditions. Negative priming does not result from previously ignoring an item. These findings strongly support the selection-feature mismatch account of negative priming and refute both the distractor inhibition and the episodic-retrieval explanations.

Conducting Research with Non-clinical Healthy Undergraduates: Does Effort Play a Role in Neuropsychological Test Performance?

Poor effort by examinees during neuropsychological testing has a profound effect on test performance. Although neuropsychological experiments often utilize healthy undergraduate students, the test-taking effort of this population has not been investigated previously. The purpose of the present study was to determine whether undergraduate students exercise variable effort in neuropsychological testing. During two testing sessions, participants (N = 36) were administered three Symptom Validity Tests (SVTs), the Test of Memory Malingering, the Dot Counting Test, and the Victoria Symptom Validity Test (VSVT), along with various neuropsychological tests. Analyses revealed 55.6% of participants in Session 1 and 30.8% of participants in Session 2 exerted poor effort on at least one SVT. Poor effort on the SVTs was significantly correlated with poor performance on various neuropsychological tests and there was support for the temporal stability of effort. These preliminary results suggest that the base rate of suboptimal effort in a healthy undergraduate population is quite high. Accordingly, effort may serve as a source of variance in neuropsychological research when using undergraduate students.

Peering into Large Lectures: Examining Peer and Expert Mark Agreement Using peerScholar, an Online Peer Assessment Tool

As class sizes increase, methods of assessments shift from costly traditional approaches (e.g. expert-graded writing assignments) to more economic and logistically feasible methods (e.g. multiple-choice testing, computer-automated scoring, or peer assessment). While each method of assessment has its merits, it is peer assessment in particular, especially when made available online through a Web-based interface (e.g. our peerScholar system), that has the potential to allow a reintegration of open-ended writing assignments in any size class - and in a manner that is pedagogically superior to traditional approaches. Many benefits are associated with peer assessment, but it was the concerns that prompted two experimental studies (n = 120 in each) using peerScholar to examine mark agreement between and within groups of expert (graduate teaching assistants) and peer (undergraduate students) markers. Overall, using peerScholar accomplished the goal of returning writing into a large class, while producing grades similar in level and rank order as those provided by expert graders, especially when a grade accountability feature was used.

Turning an advantage into a disadvantage: ambiguity effects in lexical decision versus reading tasks.

When performing a lexical decision task, participants can correctly categorize letter strings as words faster if they have multiple meanings (i.e., ambiguous words) than if they have one meaning (i.e., unambiguous words). In contrast, when reading connected text, participants tend to fixate longer on ambiguous words than on unambiguous words. Why are ambiguous words at an advantage in one word recognition task, and at a disadvantage in another? These disparate results can be reconciled if it is assumed that ambiguous words are relatively fast to reach a semantic-blend state sufficient for supporting lexical decisions, but then slow to escape the blend when the task requires a specific meaning be retrieved. We report several experiments that support this possibility.

Negative priming effects that are bigger than a breadbox: Attention to distractors does not eliminate negative priming, it enhances it

In a series of experiments, we examined the effect of requiring subjects to attend to distractors in a test of negative priming. This was accomplished by using a referent size-selection task in which subjects were instructed to name the larger animal and to ignore the smaller animal in a word pair. The result was a quadrupling of the standard negative priming effect, suggesting that negative priming not only occurs for attended distractors, it is actually enhanced. We demonstrated that this enhancement of the effect was not due solely to increased latencies in the referent size-selection task, because neither decreasing base response times in other referent size-selection tasks nor increasing base response times in typical color-selection tasks substantially affected the respective negative priming effects. Although these findings can be accommodated within current theories of negative priming, they challenge the basic assumption that the negative priming effect arises because the critical item was ignored or not attended to on the prime trial.

Negative Priming without Overt Prime Selection

The procedure typically used to demonstrate negative priming requires subjects to respond to one of two simultaneously presented stimuli across two consecutive displays. Negative priming is defined by slower responses to targets in the second display that appeared as distractors in the first display, than to targets in the second display that did not appear in the first display. It is widely assumed that negative priming occurs as a result of the selection that occurs in the first display. In the present article, we show that negative priming can be observed without requiring subjects to respond selectively to one of two items in the first display. We argue that this result is useful for two reasons. First, it points out a fundamental misunderstanding concerning the procedure required to measure negative priming, a misunderstanding that has shaped much of the theoretical work done in this area. Second, we suggest that the procedure introduced here is of considerable utility in evaluating theoretical accounts of negative priming. To demonstrate this utility we report the results of two studies that assess the code co-ordination account of negative priming.

The eyes know what you are thinking: Eye movements as an objective measure of mind wandering

Paralleling the recent work by Reichle, Reineberg, and Schooler (2010), we explore the use of eye movements as an objective measure of mind wandering while participants performed a reading task. Participants were placed in a self-classified probe-caught mind wandering paradigm while their eye movements were recorded. They were randomly probed every 2-3 min and were required to indicate whether their mind had been wandering. The results show that eye movements were generally less complex when participants reported mind wandering episodes, with both duration and frequency of within-word regressions, for example, becoming significantly reduced. This is consistent with the theoretical claim that the cognitive processes that normally influence eye movements to enhance semantic processing during reading exert less control during mind wandering episodes.