Tom Heyman

The influence of working memory load on semantic priming

The present research examines the nature of the different processes that have been proposed to underlie semantic priming. Specifically, it has been argued that priming arises as a result of automatic target activation and/or the use of strategies like prospective expectancy generation and retrospective semantic matching. This article investigates the extent that these processes rely on cognitive resources by experimentally manipulating working memory load. To disentangle prospective and retrospective processes, prime-target pairs were selected such that they were symmetrically associated (e.g., answer-question; SYM) or asymmetrically associated in either the forward direction (e.g., panda-bear; FA) or the backward direction (e.g., ball-catch; BA). The results showed that priming for FA pairs completely evaporated under a high working memory load but that it remained stable for BA and SYM pairs. This was taken to mean that prospective processes, which are assumed to cause FA priming, require cognitive resources, whereas retrospective processes, which lead to BA priming, are relatively effortless.

Frequent words do not break continuous flash suppression differently from infrequent or nonexistent words: implications for semantic processing of words in the absence of awareness.

Continuous flash suppression (CFS) has been used as a paradigm to probe the extent to which word stimuli are processed in the absence of awareness. In the two experiments reported here, no evidence is obtained that word stimuli are processed up to the semantic level when suppressed through CFS. In Experiment 1, word stimuli did not break suppression faster than their pseudo-word variants nor was suppression time modulated by word frequency. Experiment 2 replicated these findings, but more critically showed that differential effects can be obtained with this paradigm using a simpler stimulus. In addition, pixel density of the stimuli did prove to be related to suppression time in both experiments, indicating that the paradigm is sensitive to differences in detectability. A third and final experiment replicated the well-known face inversion effect using the same set-up as Experiments 1 and 2, thereby demonstrating that the employed methodology can capture more high-level effects as well. These results are discussed in the context of previous evidence on unconscious semantic processing and two potential explanations are advanced. Specifically, it is argued that CFS might act at a level too low in the visual system for high-level effects to be observed or that the widely used breaking CFS paradigm is merely ill-suited to capture effects in the context of words.

Some Differences in Some: Examining Variability in the Interpretation of Scalars Using Latent Class Analysis

The present study investigated people’s understanding of underinformative sentences like ‘Some oaks are trees’. Specifically, the scalar term ‘some’ can be interpreted pragmatically, Not all oaks are trees, or logically, some and possibly all oaks are trees. The aim of this study was to capture the interindividual variability in the interpretation of such sentences. In two experiments, participants provided truth value judgments for 20 underinformative sentences on which a latent class analysis was performed. The results revealed three latent classes: a consistent pragmatic group, a consistent logical group and an inconsistent group. Furthermore, we examined whether this interindividual variability could be explained by text characteristics, response times, cognitive abilities and personality traits. The results showed that only participants’ response times to the underinformative sentences could predict class membership. Specifically, the slower participants responded, the more likely they were to interpret underinformative sentences consistently pragmatic or inconsistent instead of consistently logical.

Using the speeded word fragment completion task to examine semantic priming

The present research investigates semantic priming with an adapted version of the word fragment completion task. In this task, which we refer to as the speeded word fragment completion task, participants need to complete words such as lett_ce (lettuce), from which one letter was omitted, as quickly as possible. This paradigm has some interesting qualities in comparison with the traditionally used lexical decision task. That is, it requires no pseudowords, it is more engaging for participants, and most importantly, it allows for a more fine-grained investigation of semantic activation. In two studies, we found that words were completed faster when the preceding trial comprised a semantically related fragment such as tom_to (tomato) than when it comprised an unrelated fragment such as guit_r (guitar). A third experiment involved a lexical decision task, to compare both paradigms. The results showed that the magnitude of the priming effect was similar, but item-level priming effects were inconsistent over tasks. Crucially, the speeded word fragment completion task obtained strong priming effects for highly frequent, central words, such as work, money, and warm, whereas the lexical decision task did not. In a final experiment featuring only short, highly frequent words, the lexical decision task failed to find a priming effect, whereas the fragment completion task did obtain a robust effect. Taken together, these results suggest that the speeded word fragment completion task may prove a viable alternative for examining semantic priming.

Using Interocular Suppression and EEG to Study Semantic Processing

Presenting an image to one eye and a dissimilar image to the other eye induces a phenomenon called binocular rivalry, in which the conscious percept alternates between the two dissimilar images despite constant retinal input. This technique has provided some insight regarding the levels of visual

On the Cost of Knowledge: Evaluating the Boycott against Elsevier

In the pre-Internet era, commercial publishers, such as Elsevier and Wiley, played an important role in disseminating new scientific ideas and discoveries. The emergence of the Internet has forced publishers to rethink their business model (Cope and Phillips, 2014), partly because scientists could, in principle, easily reach a broad audience and cut out the proverbial middleman. It is fair to say that commercial publishers adapted quite successfully as they arguably remain key players in the scientific publishing landscape (Cope and Kalantzis, 2014; Lariviere et al., 2015). However, academics have been criticizing publishers’ business practices for over a decade now [e.g., Dyer (2004)] and the call for reform has grown even louder in the past couple of years (Corbyn, 2012; Flood, 2012; Cope and Kalantzis, 2014). A prime example of such a reform initiative is the Cost of Knowledge campaign. Launched in response to a blog post by prominent mathematician Gowers (2012), the campaign specifically targets the publishing house Elsevier, denouncing its attempts to restrict the free exchange of information, the exorbitantly high prices for subscriptions, and the practice of selling journals in large bundles featuring many unwanted titles.1 Signatories of the petition pledge to not referee for, publish in, or do editorial work for Elsevier journals. Roughly 4 years after the boycott started, it seems appropriate to evaluate its impact and contemplate its future. As a result of the boycott, several academics resigned from the editorial boards of numerous Elsevier journals. Moreover, the entire editorial board of the Elsevier journal Lingua resigned and started a new, open access journal called Glossa (Greenberg, 2015). The boycott thus changed the publishing landscape to a certain extent but not as drastically as the organizers might have hoped. More importantly, however, over 80% of the nearly 16,000 signatories pledged to not publish in an Elsevier journal. This could gradually reduce the quality and thus the relevance of those journals. However, such a process takes time, and its effects may not be readily discernible. One might, therefore, wonder whether it provides much leverage in persuading Elsevier, or any other publisher for that matter, to change its policies. Moreover, one could question the feasibility of such a (long-term) commitment, especially the “won’t publish” pledge. Given the seemingly ever-growing emphasis in academia on publishing papers in high impact journals, it might put a non-trivial burden on one’s career. From previous studies, and perhaps personal experience, we know that good resolutions sometimes run aground (Norcross et al., 2002). But what about the “won’t publish” commitment? Do signatories stick to their guns and indeed refrain from publishing in Elsevier journals? This is an interesting question because the success of such an initiative largely depends on the persistence of its signatories. Put differently, a petition such as the Cost of Knowledge can influence policy decisions to the extent that its signatories remain committed.

The (un)reliability of item-level semantic priming effects

Many researchers have tried to predict semantic priming effects using a myriad of variables (e.g., prime–target associative strength or co-occurrence frequency). The idea is that relatedness varies across prime–target pairs, which should be reflected in the size of the priming effect (e.g., cat should prime dog more than animal does). However, it is only insightful to predict item-level priming effects if they can be measured reliably. Thus, in the present study we examined the split-half and test–retest reliabilities of item-level priming effects under conditions that should discourage the use of strategies. The resulting priming effects proved extremely unreliable, and reanalyses of three published priming datasets revealed similar cases of low reliability. These results imply that previous attempts to predict semantic priming were unlikely to be successful. However, one study with an unusually large sample size yielded more favorable reliability estimates, suggesting that big data, in terms of items and participants, should be the future for semantic priming research.

Relationship between Extensions and Intensions in Categorization: A Match Made in Heaven?.

The present study investigated the relationship between category extension and intension for 11 different semantic categories. It is often tacitly assumed that there is a (strong) extension–intension link. However, a recent study by Hampton and Passanisi (2016) examining the patterns of stable individual differences in concepts across participants called this hypothesis into question. To conceptually replicate their findings, two studies were conducted. We employed a category judgment task to measure category extensions, whereas a property generation (in Study 1) and property judgment task (Study 2) were used to measure intensions. Using their method, that is, correlating extension and intension similarity matrices, we found nonsignificant correlations in both studies, supporting their conclusion that similarity between individuals for extensional judgments does not map onto similarity between individuals for intensional judgments. However, multilevel logistic regression analyses showed that the properties a person generated (Study 1) or endorsed (Study 2) better predicted her own category judgments compared to other people’s category judgments. This result provides evidence in favor of a link between extension and intension at the subject level. The conflicting findings, resulting from two different approaches, and their theoretical repercussions are discussed.

Feature taxonomy: What type of features do children associate with categories and how do they fare in predicting category judgments?

The present study investigates category intension in school-aged children and adults at two different levels of abstraction (i.e., superordinate and basic level) for two category types (i.e., artefacts and natural kinds). We addressed two critical questions: what kind of features do children and adults generate to define semantic categories and which features predict category membership judgment best at each abstraction level? Overall, participants generated relatively more entity features for natural kinds categories, compared to artefact categories, as well as for basic level categories, compared to superordinate categories. Furthermore, the results showed that older children and adults generated relatively more entity features than younger children. Finally, situation features play the most important role in the prediction of category judgments at both levels of abstraction. Theoretical implications and comparable results from previous studies are described in detail.