Todd A. Kahan

Dissociated backward priming effects in lexical decision and pronunciation tasks.

Backward priming was examined at 150- and 500-msec prime-target stimulus onset asynchronies (SOAs) using visually presented primes and targets in lexical decision and pronunciation tasks. Two kinds of backward relations were used: compound items for which targets and primes formed a word in the backward direction (e.g., prime: HOP; target:bell), and noncompound items for which targets and primes did not form a word but were associatively related in the backward but not the forward direction (e.g., prime: BABY; target:stork). Results showed that backward priming effects were equivalent for compounds and noncompounds. However, for lexical decisions, backward priming occurred at both SOAs, whereas for pronunciation, it occurred only at the 150-msec SOA. We discuss how this SOA-dissociated backward priming effect in lexical decision and pronunciation tasks poses a serious challenge for all theories of semantic priming.

RESPONSE CONFLICT REVERSES PRIMING : A REPLICATION

Subjects named target words that followed a masked prime word of 33-msec (Experiments 1A and 1B) or 200-msec (Experiment 2) duration. The target word was either presented alone or accompanied by an interleaved distractor word. Targets presented alone were named more quickly following an identical prime than following an unrelated prime (repetition priming). In Experiment 1A, targets with distractors were named more slowly following an identical prime than following an unrelated prime (negative priming), replicating Milliken, Joordens, Merikle, and Seiffert (Psychological Review, 1998). In Experiments 1B and 2, repetition priming was reduced, although not reversed, for targets with distractors. The results of all three experiments are opposite to the usual finding of enhanced priming for perceptually degraded targets and suggest that response conflict engages retrospective mechanisms that counteract the facilitatory effects of priming.

Negative Priming From Masked Words: Retrospective Prime Clarification or Center-Surround Inhibition?

Masked repetition and semantic priming effects were examined in 2 experiments. In Experiment 1, a masked-prime lexical decision task followed a phase of detection, semantic, or repetition judgments about masked words. In Experiment 2 participants made speeded pronunciations to target words after they tried to identify masked primes, and the proportion of semantically and identically related prime-target pairs was varied. Center-surround theory CT. H. Carr & D. Dagenbach, 1990; D. Dagenbach, T. H. Carr, & A. Wilhelmsen, 1989) predicts positive repetition priming but negative semantic priming when people attempt, but fail, to extract the meanings of masked words. A retrospective prime-clarification account, in contrast, predicts that semantic and repetition priming effects will vary (being positive or negative) as a function of expectations about the prime-target relation. The data support a retrospective prime-clarification account, which, unlike center-surround theory, correctly predicted negative repetition priming effects.

The role of valence and frequency in the emotional Stroop task

People are generally slower to name the color of emotion-laden words than they are to name that of emotionally neutral words. However, an analysis of this emotional Stroop effect (Larsen, Mercer, & Balota, 2006) indicates that the emotion-laden words used are sometimes longer, have lower frequencies, and have smaller orthographic neighborhoods than the emotionally neutral words. This difference in word characteristics raises the possibility that the emotional Stroop effect is partly caused by lexical rather than by emotional aspects of the stimuli—a conclusion supported by the finding that reaction times to name the color of low-frequency words are longer than those for high-frequency words (Burt, 2002). To examine the relative contributions of valence and frequency in color naming, we had 64 participants complete an experiment in which each of these variables was manipulated in a 3 ? 2 factorial design; length, orthographic neighborhood density, and arousal were balanced. The data indicate that valence and word frequency interact in contributing to the emotional Stroop effect.

Repetition Blindness, Forward and Backward

In these experiments, 2 letters were presented sequentially to the left and right of fixation, followed by pattern masks. Report was cued by spatial location (Experiments la, 1b, 2, 4, and 5) or temporal position (Experiments 3, 4, and 5). In all experiments, 2 identical letters on a trial resulted in reduced accuracy of report (repetition blindness; RB) for both the 1st and 2nd presented letters. This decrement was greater for the 2nd letter if subjects expected temporal cues, but tended to be greater for the 1st letter if they expected spatial cues. Analyses of errors and responses on catch trials indicated no bias against report of repetitions, and the repetition decrement did not interact with output order. The data are inconsistent with both type-refractoriness and memory-retrieval accounts of RB. A modified version of N. G. Kanwishers (1987) token-individuation theory is proposed to account for the results.

Gestalt grouping and common onset masking

A four-dot mask that surrounds and is presented simultaneously with a briefly presented target will reduce a person’s ability to identity that target if the mask persists beyond target offset and attention is divided (Enns & Di Lollo, 1997, 2000).This masking effect, referred to as common onset masking, reflectsreentrant processing in the visual systemand can best be explained with a theory of object substitution (Di Lollo, Enns, & Rensink, 2000).In the present experiments, we investigatedwhether Gestalt grouping variables would influence the strength of common onset masking.The results indicated that (1) masking was impervious to grouping by form, similarity of color, position, luminance polarity, and common region and (2) masking increased with the number of elements in the masking display.

Reading “glasses” will prime “vision,” but reading a pair of “glasses” will not

In a lexical decision task with two primes and a target, the target was preceded 300 msec by the second prime (P2) which in turn was preceded by a brief forward and backward masked first prime (P1). When P1 and P2 were unrelated, reaction times were faster when the target was related to P2 (e.g.,wave SALT ... pepper) than when the target was unrelated to P2 (and P1—e.g.,wave LOAN ... pepper). However, this semantic priming effect was reduced to statistically nonsignificant levels when P1 and P2 were repetitions of the same word. That is, priming did not occur forsalt SALT ... pepper relative toloan LOAN ... pepper. This reduction in priming was observed whether P2 and the target were strongly or weakly related. These findings raise problems for current accounts of semantic priming.

Looking at object-substitution masking in depth and motion: toward a two-object theory of object substitution.

When attention is divided, a briefly presented target surrounded by four small dots is difficult to identify when the dots persist beyond target offset, but not when these dots terminate with the target. This object-substitution masking effect likely reflects processes at both the image level and the object level. At the image level, visual contours of the mask make feature extraction difficult. Recent data (Lleras & Moore, 2003) suggest that, at the object level, an object file is created for the target-plus-mask, and this single-object token later morphs into a single-object token containing the mask alone. In the present experiments, we used stimuli presented in 3-D space and apparent motion; the results indicate that object-substitution masking also arises when the mask and the target are represented in two separate object tokens and the mask token interferes with the target token.

An examination of orthographic and phonological processing using the task-choice procedure

The task-choice procedure provides a way for assessing whether stimuli are processed immediately upon presentation and in parallel with other cognitive operations. In this procedure, the task changes on a trial-by-trial basis and the cue informing participants about the task appears either before or simultaneously with the target, which is either degraded or clear. Of interest is whether the effect of stimulus clarity will disappear when the cue is presented simultaneously with the target, suggesting capacity-free processing, or whether the effect of stimulus clarity will remain, suggesting target processing is delayed. Besner and Care developed this procedure using nonword targets and found that phonological information was not extracted in parallel with deciphering the task cue. The current experiment examined whether phonological and orthographic information could be extracted from word and nonword stimuli in a capacity-free manner. Results indicate that in both tasks some processing does occur in a capacity-free manner when words are used but not when nonwords are used. These data may be consistent with interactive activation models which posit top-down lexical connections that facilitate the extraction of sublexical codes.

Identifying words that emerge into consciousness: Effects of word valence and unconscious previewing

Words with negative valence capture attention and this increase in attentional resources typically enhances perceptual processing. Recently, data using continuous flash suppression (CFS) appear to contradict this. In prior research when Chinese words were unconsciously presented in CFS and contrast was raised until the word was identified, RTs to identify words with negative valence were slower than RTs to words with neutral valence. This result might be limited to situations where a logographic writing system is used and could reflect a type of cognitive aftereffect where previewing the word causes habituation. Data (N=60) indicate that results generalize from a logographic (Chinese) to an orthographic writing system (English). In addition, when words were previewed in CFS RTs were slowed for words with negative valence relative to words with neutral valence and this was reversed when words were shown binocularly. Implications for theories of unconscious word processing and cognitive aftereffects are discussed.