Analysing the relationship between target-to-target and distractor-to-target repetitions: Evidence for a common mechanism

In the present study an assumption of retrieval theories of negative priming was tested. In particular, retrieval theories assume that the same underlying process causes benefits in target-to-target repetition trials and cost effects in distractor-to-target repetition trials in selection tasks in which targets are accompanied by distractor stimuli. More specifically, retrieval theories predict a negative correlation: The higher the benefit in target-to-target repetition trials is, the higher the cost effect in distractor-to-target repetition trials should be. In fact, in a study with considerable power (N = 110) and a design that allowed a confound-free detection of correlations, I observed a significant negative correlation between benefit and cost effects. This result is interpreted as evidence for a common retrieval mechanism.     

Contextual cost: When a visual-search target is not where it should be

Visual search is often facilitated when the search display occasionally repeats, revealing a contextual-cueing effect. According to the associative-learning account, contextual cueing arises from associating the display configuration with the target location. However, recent findings emphasizing the importance of local context near the target have given rise to the possibility that low-level repetition priming may account for the contextual-cueing effect. This study distinguishes associative learning from local repetition priming by testing whether search is directed toward a target's expected location, even when the target is relocated. After participants searched for a T among Ls in displays that repeated 24 times, they completed a transfer session where the target was relocated locally to a previously blank location (Experiment 1) or to an adjacent distractor location (Experiment 2). Results revealed that contextual cueing decreased as the target appeared farther away from its expected location, ultimately resulting in a contextual cost when the target swapped locations with a local distractor. We conclude that target predictability is a key factor in contextual cueing.     

Reduced repetition suppression in the occipital visual cortex during repeated negative Chinese personality‐trait word processing

Reduced neural activation have been consistently observed during repeated items processing, a phenomenon termed repetition suppression. The present study used functional magnetic resonance imaging (fMRI) to investigate whether and how stimuli of emotional valence affects repetition suppression by adopting Chinese personality‐trait words as materials. Seventeen participants were required to read the negative and neutral Chinese personality‐trait words silently. And then they were presented with repeated and novel items during scanning. Results showed significant repetition suppression in the inferior occipital gyrus only for neutral personality‐trait words, whereas similar repetition suppression in the left inferior temporal gyrus and left middle temporal gyrus was revealed for both the word types. These results indicated common and distinct neural substrates during processing Chinese repeated negative and neutral personality‐trait words.     

The relationship between the objective identification threshold and priming effects does not provide a definitive boundary between conscious and unconscious perceptual processes

The Objective Threshold/Strategic Model (OT/S) proposes that strong, qualitative inferences of unconscious perception can be made if the relationship between perceptual sensitivity (typically priming effects) and stimulus visibility is nonlinear and nonmonotonic. The model proposes a nadir in priming effects at the objective identification threshold (identification d′ = 0). These predictions were tested with masked semantic priming and repetition priming of a lexical decision task. The visibility of the prime stimuli was systematically varied above and below the objective identification threshold. The obtained relationship between prime visibility and priming facilitation was nonlinear, but the results failed to confirm a nadir in priming effects at the objective identification threshold. We conclude that the objective identification threshold does not necessarily indicate the point where presumably unconscious priming effects might be inhibited by conscious cognitive processes.     

Neural enhancement and attenuation induced by repetitive recall

Learning is the process of accumulating information. Repetition can make the process of retrieving information more efficient. The mechanisms by which repetition facilitates the retrieval process, however, are not yet clear. Here, we used event-related functional magnetic resonance imaging to investigate the effects of repetition on cued recall. In this study, participants were asked to encode visually presented semantically unrelated word pairs. The word presented on the left side served as the cue, and the word presented on the right side was the target. In the first test phase, participants were presented with the cue and asked to recall the associated word (target) from the study phase. The second test phase was performed 20 min later using the same method. Participants responded orally during the interval between image acquisitions, and no feedback was provided. Neural activity for identical stimuli and responses across the two tests were compared. As compared with the first test phase, the right dorsolateral prefrontal, bilateral inferior parietal, and precuneus regions showed greater activity and the left inferior frontal areas showed reduced activity during the second test phase. These shifts in neural activity that occurred with repetition may reflect the dynamics of the retrieval process.     

Effect of relation availability on the interpretation and access of familiar noun–noun compounds

Two experiments investigate whether relations that link the constituents of compounds during compound formation (e.g., teapot is formed by combining tea and pot using the relation head noun FOR modifier) also influence the processing of familiar compounds. Although there is evidence for the use of such relations in forming compounds, whether such relations affect the processing of familiar compounds is unknown. The data show clear effects of repetition and relational priming for written words on both a sense-nonsense task and a lexical decision task. These results indicate that the relation linking the constituents of familiar compounds is important to their access and use.     

Repeated priming increases memory accessibility in infants

In previous research on priming (reactivation) with 3-month-olds, two primes recovered a forgotten memory faster than one, suggesting that prior priming had increased the accessibility of the forgotten memory. Exploiting the fact that the minimum duration of a prime indexes the accessibility of the forgotten memory, we currently examined whether prior priming also reduces the minimum effective prime duration. In three experiments, 60 3-month-olds learned an operant task, forgot it, and then were exposed to successive primes either 1 day and 1 week after forgetting (Experiment 1) or 1 and 2 weeks after forgetting (Experiment 2). In both cases, prior priming reduced the minimum duration of the second prime, a result that was independent of the duration of the first prime (Experiment 3). These findings confirm that priming increases the accessibility of a latent memory and raise the possibility that repeated priming underlies the extended memorability of persons and events that infants encounter sporadically.     

On the fate of distractor stimuli in rapid serial visual presentation

Observers demonstrate an impaired ability to report the second of two targets in a rapid serial visual presentation (RSVP) stream if it appears within 500 ms of the first target--a phenomenon known as the attentional blink. This study investigated the fate of stimuli in dual-target RSVP streams that do not require report--the distractors. In five experiments, observers viewed dual-target RSVP streams where the items flanking Target 1 either had the same identity (repeats) or a different identity (non-repeats). Repeated distractors reduced the attentional blink, but only if two conditions were met (1) the items flanking Target 1 were featurally identical and (2) the distractors were drawn from a different alphanumeric category to the targets (e.g. digits vs. letters). We interpret this reduced blink magnitude in the repeat trials as evidence that in RSVP streams distractor items that appear in close temporal proximity to Target 1 are inhibited and we propose that this inhibition occurs both at the level of alphanumeric features and abstract identities.     

Adaptive Changes in Grain-size in Morphological Processing

Substantial neurobiological data indicate that the dominant cortical region for printed-word recognition shifts from a temporo-parietal (dorsal) to an occipito-temporal (ventral) locus with increasing recognition experience. The circuits also have different characteristic speeds of response and word preferences. Previous evidence suggested that grain-size increased with word repetition. In the present experiment, we examined morpheme boundaries imposing a limitation on steadily increasing grain-size within a word. We manipulated the type font within a word so that it either emphasized or disguised the word’s morphemic structure. The results showed that, even after several repetitions, morphemic structure had an effect on word recognition, although eventually it did become nonsignificant. Thus, the spread of grain-size with repetition does not appear to cross morpheme boundaries easily. These results suggest that skilled, experienced, word recognition may achieve its speed, substantially, by unitizing the word’s letters within but not across its morphological units.     

Looks aren’t Everything: Pseudohomophones Prime Words but Nonwords do not

After examining literature that deals with phonological and orthographic effects associated with pseudohomophones, the current effort deviates from the norm by using fewer pseudohomophones (20) and extending the lags between primes and targets (M=8). Word and pseudohomophone primes were found to facilitate lexical decision response latencies to word targets. Response latencies to word targets were not influenced by nonword primes, however. The presence of pseudohomophone effects was demonstrated by longer response latencies and higher error rates for pseudohomophones (e.g., DREEM) that were equated in orthography to nonword controls (e.g., DROAM). Despite the frequency effect observed for base words, the pseudohomophones did not exhibit an effect of base word frequency. The results suggest that phonological codes exert an influence on lexical representation but are not frequency sensitive.