Francesca Peressotti

The role of letter identity and letter position in orthographic priming.

Four experiments are reported investigating orthographic priming effects in French by varying the number and the position of letters shared by prime and target stimuli. Using both standard masked priming and the novel incremental priming technique (Jacobs, Grainger, & Ferrand, 1995), it is shown that net priming effects are affected not only by the number of letters shared by prime and target stimuli but also by the number of letters in the prime not present in the target. Several null results are thus explained as a tradeoff between the facilitation generated by common letters and the inhibition generated by different letters. Inhibition was significantly reduced when different letters were replaced by nonalphabetic symbols. Facilitation effects disappeared when the common letters did not have the same relative position in the prime and target strings, thus supporting a relative-position coding scheme for letters in words.

Letter-position coding in random consonant arrays

The processing of letter-position information in randomly arranged consonant strings was investigated using a masked prime variant of the alphabetic decision (letter/nonletter classification) task. In Experiment 1, primes were uppercase consonant trigrams (e.g., FMH) and targets were two uppercase Xs accompanied by the target letter or a nonletter (e.g., XMX, X%X). Response times were systematically faster when target letters were present in the prime string than when target letters were not present in the prime string. These constituent letter-priming effects were significantly stronger when the target letter appeared in the same position in the prime and target stimuli. This contrast between position-specific and position-independent priming was accentuated when subjects responded only when all the characters in the target string were letters (multiple alphabetic decision) in Experiments 2 and 3. In Experiment 4, when prime exposure duration was varied, it was found that position-specific priming develops earlier than position-independent priming. Finally, Experiment 5 ruled out a perceptual-matching interpretation of these results. An interpretation is offered in terms of position-specific and position-independent letter-detector units in an interactiveactivation framework.

ERP evidence for ultra-fast semantic processing in the picture-word interference paradigm

We used the event-related potential (ERP) approach combined with a subtraction technique to explore the timecourse of activation of semantic and phonological representations in the picture–word interference paradigm. Subjects were exposed to to-be-named pictures superimposed on to-be-ignored semantically related, phonologically related, or unrelated words, and distinct ERP waveforms were generated time-locked to these different classes of stimuli. Difference ERP waveforms were generated in the semantic condition and in the phonological condition by subtracting ERP activity associated with unrelated picture–word stimuli from ERP activity associated with related picture–word stimuli. We measured both latency and amplitude of these difference ERP waveforms in a pre-articulatory time-window. The behavioral results showed standard interference effects in the semantic condition, and facilitatory effects in the phonological condition. The ERP results indicated a bimodal distribution of semantic effects, characterized by the extremely rapid onset (at about 100 ms) of a primary component followed by a later, distinct, component. Phonological effects in ERPs were characterized by components with later onsets and distinct scalp topography of ERP sources relative to semantic ERP components. Regression analyses revealed a covariation between semantic and phonological behavioral effect sizes and ERP component amplitudes, and no covariation between the behavioral effects and ERP component latency. The early effect of semantic distractors is thought to reflect very fast access to semantic representations from picture stimuli modulating on-going orthographic processing of distractor words.

The Picture-Word Interference Effect Is Not a Stroop Effect

A psychological refractory period (PRP) paradigm was used to isolate the locus of the picture—word interference effect along the chain of processes subtended in name production. Two stimuli were presented sequentially on each trial, separated by a varying stimulus onset asynchrony (SOA). The first stimulus, S1, was a tone that required a manual response. The second stimulus, S2, was a picture—word stimulus associated with picture naming. The distractor word was conceptually related to the picture on half of the trials, and unrelated in the other trials. A picture—word interference effect was found at long SOA, but not at short SOA. Such underadditive interaction between SOA and semantic relatedness suggests strongly that the locus of the picture—word interference effect is functionally earlier than the PRP effect locus. The results are discussed in relation to models of word production suggesting the involvement of central mechanisms in the selection of lexical output.

Bidirectional semantic priming in the attentional blink

The time course of semantic priming between two associated words was tracked using rapid serial visual presentation of two synchronized streams of stimuli appearing at about 20 items/sec, each stream including a target word. The two words were semantically related or unrelated and were separated by stimulus onset asynchronies (SOAs) of 0–213 msec. Accuracy in reporting the first target (T1) versus the second target (T2) has been shown to interact dramatically with SOA over this range. The materials were in English in Experiment1 and Italian in Experiment2. T1 was semantically primed only at short SOAs, whereas T2 was primed at all SOAs (Experiment 1) or at all SOAs except the shortest one (Experiment2). The results indicate a strong competition between target words early in processing, with T2 often becoming the first word identified at short SOAs, thus priming T1.

On recognizing proper names: the orthographic cue hypothesis.

Five experiments investigated the recognition of proper names and common nouns using the lexical decision paradigm. In Experiments 1-3 the case of the initial letter of written stimuli was systematically varied. An advantage was consistently found for proper names written with the first letter in capital. Crucially, response times to proper names with the first letter in lowercase and to common nouns irrespective of the case of the first letter did not differ from each other. No difference between proper names and common nouns emerged in Experiment 4 where the stimuli were presented auditorily, and in Experiment 5 where a visual lexical decision task was performed with illegal non-words. The pattern of results shows that the proper name advantage is orthographic in nature and rules out an account in terms of semantic, morphological or other lexical variables. A model is proposed in which information about the case of the first letter is specified in the abstract multidimensional orthographic representation mediating written word recognition.

Lexical Effects in Naming Pseudowords in Shallow Orthographies: Further Empirical Data

Pseudoword reading in Italian, a language with a regular but context-sensitive mapping from orthography to phonology, was investigated. Pairs of pseudowords were derived from words by changing the vowel following a target letter. In 1 of the pseudowords, pronunciation of the target grapheme was the same as in the original word (consistent), whereas in the other it was different (inconsistent). In Experiment 1, pseudowords were mixed with words. In the other 2 experiments, only pseudowords were presented. Consistency effects in naming the pseudowords emerged in Experiment 1 but disappeared in Experiments 2 and 3. The pattern of results constrains the functional architecture of reading models because the list composition effect is compatible with a dual-route model but is difficult to reconcile with a single-route framework.

New evidence for the perceptual precedence of global information

Two experiments are reported investigating the order in which global and local information of visual forms is processed. Subjects were presented with compound stimuli and were asked to identify the local level, always consisting of small letters. At the global level, the stimuli could be either large letters, consistent or inconsistent with the local level, or meaningless patterns derived from the large letters by modifying the spatial relations among segments. Results showed that inconsistent stimuli were responded to more slowly than both consistent stimuli and meaningless patterns, which did not differ from each other. This was true both when letters and patterns were presented intermixed, as in experiment 1 or separately, as in experiment 2. The pattern obtained accords well with predictions derived from the perceptual precedence hypothesis which states that global information becomes available at a faster rate than local information. No support for the alternative, post-perceptual, hypothesis was found.

What Phonological Facilitation Tells about Semantic Interference: A Dual-Task Study

Despite increasing interest in the topic, the extent to which linguistic processing demands attentional resources remains poorly understood. We report an empirical re-examination of claims about lexical processing made on the basis of the picture–word interference task when merged in a dual-task psychological refractory period (PRP) paradigm. Two experiments were conducted in which participants were presented with a tone followed, at varying stimulus onset asynchronies (SOAs), by a picture–word stimulus. In Experiment 1, the phonological relatedness between pictures and words was manipulated. Begin- and end-related words decreased picture naming latencies relative to unrelated words. This effect was additive with SOA effects. In Experiment 2, both the semantic and the phonological relatedness between pictures and words were manipulated. Replicating Experiment 1, effects arising from the phonological manipulation were additive with SOA effects on picture naming latencies. In contrast, effects arising from the semantic manipulation were under additive with SOA effects on picture naming latencies, that is, semantic interference decreased as SOA was decreased. Such contrastive pattern suggests that semantic and phonological effects on picture naming latencies are characterized by distinguishable sources, the former prior to the PRP bottleneck and the latter at the PRP bottleneck or after. The present findings are discussed in relation to current models of language production.

Reading aloud: The cumulative lexical interference effect

Picture naming shows a cumulative semantic interference effect: Latency for naming a target picture increases as a function of the number of pictures semantically similar to the target that have previously been named (Howard, Nickels, Coltheart, & Cole-Virtue, Cognition 100:464–482, 2006). Howard and colleagues, and also Oppenheim, Dell, and Schwartz (Cognition 114:227–252, 2010), argued that this occurs because of the joint presence in the picture-naming system of three critical properties: shared activation, priming, and competition. They also discussed the possibility that whenever any cognitive system possesses these three properties, a cumulative similarity-based interference effect from repeated use of that cognitive system will occur. We investigated this possibility by looking for a cumulative lexical interference effect when the task is reading aloud: Will the latency of reading a target word aloud increase as a function of the number of words orthographically/phonologically similar to the target that have previously been read aloud? We found that this was so. This supports the general idea that cumulative similarity-based interference effects will arise whenever any cognitive system that possesses the three key properties of shared activation, priming, and competition is repeatedly used.