Lexical decision in sentences: Effects of syntactic structure

A lexical decision paradigm was used to examine syntactic influence on word recognition in sentences. Initial fragments of sentences were presented visually (CRT display) one word at a time (at reading speeds), from left to right. The string terminated with the appearance of a lexical decision target. The grammatical structure of the incomplete sentence affected lexical decision reaction time (RT). In Experiment 1, modal verb contexts followed by main verb targets and preposition contexts followed by noun targets produced lower RTs than did the opposite pairings (i.e., modal/noun and preposition/verb). In Experiment 2, transitive verb contexts followed by noun targets and subject noun phrase contexts followed by verb targets yielded lower RTs than did the opposite pairings. Similar contrasts for adjective targets did not yield comparable effects in Experiment 2, but did when the adjective was the head of a predictable phrase (Experiment 4). In Experiment 3, noun targets yielded lower RTs than did verb targets after contexts of a transitive verb followed by a prepositional phrase. An account of these effects is offered in terms of parsing constraints on phrasal categories.     

Coactivation in the perception of redundant targets

Reaction time (RT) to redundant stimuli was investigated while controlling for distraction effects and response competition. In Experiment 1, a redundancy gain was found for 2 target letters with identical features (redundant) compared to trials in which 2 different targets shared the same response assignment (compatible) indicating coactivation of stimulus inputs. No difference in RTs was found between compatible displays and displays containing 2 targets with different responses (incompatible), suggesting (with other evidence) that letters were serially processed. In Experiment 2, a redundancy gain was again found. Unlike in Experiment 1, incompatible displays produced response competition, indicating a redundancy gain with parallel processing. Three forms of redundancy gains operating under specific conditions are discussed.     

注意转移在负相容效应产生中的作用:独立还是伴随*

采用两个实验设计,在确保负相容效应(NCE)的产生主要来自反应抑制贡献的实验范式基础上加入引发显性注意转移的目标刺激,探讨了注意转移在负相容效应产生中的作用。具体来说,实验一在经典NCE范式中加入中性目标刺激,并操纵启动与目标的关系。发现,不相容条件下的反应时最短,无关条件次之,相容条件下最长。证明在该范式中反应抑制在NCE的产生中占主导地位。实验二则在实验一范式的基础上,加入左、中、右呈现的加号目标刺激。发现,两种目标类型的反应时结果模式均与实验一相似。结果表明,注意转移并非如Cole和Kuhn(2010)提出的能够独立引发NCE,它只是伴随NCE的抑制加工过程而出现,且其加工模式与抑制加工模式类似。     

Visual search for dimensionally redundant pop-out targets: Redundancy gains in compound tasks

Two visual search experiments investigated the detection of odd-one-out feature targets redundantly defined on multiple dimensions. Targets differed from the distractors in either orientation or colour or both (redundant targets). In Experiment 1, the three types of target were presented either in separate trial blocks or randomized within blocks, and the task involved either a simple target detection response or a “compound” response based on the position of dials inside the target. Mean reaction times (RTs) were faster to redundant targets than to singly defined targets, with greater gains in simple detection than in compound tasks. Further, simple detection RTs to redundant targets were faster than the fastest RTs to singly defined targets, violating Miller's (1982) “race model inequality” (RMI). Experiment 2 showed that, with compound tasks, mean RT redundancy gains (and violations of the RMI) depend on practice. The results suggest that separate colour and orientation feature contrast signals coactivate perceptual mechanisms involved in target detection.     

Attentional priming and visual search in pigeons

Advance information about a target's identity improved visual search efficiency in pigeons. Experiments 1 and 2 compared information supplied by visual cues with information supplied by trial sequences. Reaction times (RTs) were lower when visual cues signaled a single target rather than two. RTs were (Experiment 1) or accuracy improved (Experiment 2) when a sequence of trials presented a single target rather than a mixture of 2. Experiments 3, 4, and 5 considered the selectivity of visual priming by introducing probe trials that reversed the usual cue-target relationship. RT was higher following such miscues than following the usual 1- or 2- target cuing relationships (Experiment 3); the miscuing effect persisted over variations in the target's concealment (Experiments 4 and 5), but did not occur when the target was presented alone (Experiment 4). The findings indicate that priming modifies an attentional mechanism and suggest that this effect accounts for search images.     

Distinct,but top-down modulable color and positional priming mechanisms in visual pop-out search

Three experiments examined reaction time (RT) performance in visual pop-out search. Search displays comprised of one color target and two distractors which were presented at 24 possible locations on a circular ellipse. Experiment 1 showed that re-presentation of the target at a previous target location led to expedited RTs, whereas presentation of the target at a distractor location led to slowed RTs (relative to target presentation at a previous empty location). RTs were also faster when the color of the target was the same across consecutive trials, relative to a change of the target’s color. This color priming was independent of the positional priming. Experiment 2 revealed larger positional facilitation, relative to Experiment 1, when position repetitions occurred more likely than chance level; analogously, Experiment 3 revealed stronger color priming effects when target color repetitions were more likely. These position and color manipulations did not change the pattern of color (Experiment 2) and positional priming effects (Experiment 3). While these results support the independency of color and positional priming effects (e.g., Maljkovic and Nakayama in Percept Psychophys 58:977–991, 1996), they also show that these (largely ‘automatic’) effects are top-down modulable when target position and color are predictable (e.g., Müller et al. in Vis Cogn 11:577–602, 2004).     

The gap effect in newborns

In four experiments we investigated the gap effect in infants within the first 3 days of life. Reaction times (RTs) to make a saccade to a peripheral target were measured on gap trials, in which the central fixation stimulus went off 500 ms before target presentation, and on overlap trials, in which the central fixation stimulus remained on. In every experiment the fixation stimulus was a flashing light. The target stimulus was a schematic face in Experiment 1, a flashing light shown at 20° eccentricity in Experiment 2, a flashing light shown at 30° eccentricity in Experiment 3, and an upside-down schematic face in Experiment 4. In Experiments 1–3 a gap effect was found. That is, RT was faster on gap than on overlap trials. In contrast, the gap effect was absent in Experiment 4. These findings are consistent with the view that the superior colliculus plays a major role in producing the gap effect at birth.     

Identification and categorization in visual search

Seven experiments were addressed to the general question of whether the identification of letters and numbers is a more rapid process than the categorization of such stimuli. Subjects were required to make a single response if a target stimulus specified by name (e.g., “A,” “2”) or designated by category class alone (e.g., “letter,” “number”) was presented in a trial. The principal findings were: (1) identification reaction times (RTs) were faster than categorization RTs: (2) RTs for targets shown without a context were faster than RTs for targets shown in the context of other stimuli; (3) identification RTs for targets shown in the context of stimuli from a different conceptual-taxonomic category were faster than RTs for targets shown in the context of stimuli from the same category only when target-context stimulus discriminability differencet were optimized. The results were interpreted in terms of a two-stage processing model in which context face,ors affect the duration of an initial encoding-scanning stage and search instruction (effective memory size) factors affect the duration of the memory comparison stage.     

Differential effects of voluntary expectancies on reaction times and event-related potentials: evidence for automatic and controlled expectancies.

Expectancy has been used to explain the effects of stimulus sequences both on reaction times (RTs) and on the P300 component of the human event-related potential. However, there are conflicting views about the control obtainable over these underlying expectancies. We compared the effects of voluntary expectancies for stimulus changes or repetitions in random tone series on RTs and the P300. Ss responded according to either stimulus identity (Experiment 1) or stimulus sequence (Experiment 2). In both experiments RTs were strongly affected by event expectedness. P300 amplitude, on the other hand, was affected (as a trend) only in Experiment 2. The results suggest that there are at least 2 types of "expectancy", one that is largely automatic and inflexible, reflected in P300 amplitude, and a second, controlled process that is reflected mainly in RT. The latter type of expectancy appears to affect processing stages beyond stimulus evaluation and classification.     

Response times and eye movements in feature and conjunction search as a function of target eccentricity

In four experiments, saccadic eye movements, reaction times (RTs), and accuracy were measured as observers searched for feature or conjunction targets presented at several eccentricities. A conjunction search deficit, evidenced by a large eccentricity effect on RTs, accuracy, and number of saccades, was seen in Experiments 1A and 1B. Experiment 2 indicated that, when saccades were precluded, there was an even larger eccentricity effect for conjunction search targets. In Experiment 3, practice in a conjunction search task allowed both RT and number of saccades to become independent of eccentricity. Additionally, there was evidence of feature-based selectivity in that observers were more likely to fixate distractors that had the same contrast as the target. Results are consistent with the view that the oculomotor and attentional systems are functionally linked and provide constraints for models of visual attention and search.     

Display size effects in visual search: Analyses of reaction time distributions as mixtures

In a reanalysis of data from Cousineau and Shiffrin (2004) and two new visual search experiments, we used a likelihood ratio test to examine the full distributions of reaction time (RT) for evidence that the display size effect is a mixture-type effect that occurs on only a proportion of trials, leaving RT in the remaining trials unaffected, as is predicted by serial self-terminating search models. Experiment 1 was a reanalysis of Cousineau and Shiffrin's data, for which a mixture effect had previously been established by a bimodal distribution of RTs, and the results confirmed that the likelihood ratio test could also detect this mixture. Experiment 2 applied the likelihood ratio test within a more standard visual search task with a relatively easy target/distractor discrimination, and Experiment 3 applied it within a target identification search task within the same types of stimuli. Neither of these experiments provided any evidence for the mixture-type display size effect predicted by serial self-terminating search models. Overall, these results suggest that serial self-terminating search models may generally be applicable only with relatively difficult target/distractor discriminations, and then only for some participants. In addition, they further illustrate the utility of analysing full RT distributions in addition to mean RT.     

A semantic memory sentence verification model based on relative judgment theory

A subjective referent model of sentence verification in semantic memory tasks based on the relative judgment theory of Link and Heath (1975), together with the derivation of a discriminability index, are presented in this paper. An attractive feature of the model is its consideration of both error rates and response times (RTs) in the calculation of the discriminability index. The model is also able to account for the frequent finding in semantic memory tasks that error RTs are longer than correct RTs. A partial replication of Experiment 2 of McCloskey and Glucksberg's (1979) sentence verification context effect studies, in which we employed 44 subjects and 28 categories, and controlled for item familiarity, revealed that error RTs were consistently longer than correct RTs--a finding inconsistent with the McCloskey and Glucksberg property comparison model, but in accord with the subjective referent model. An important fortuitous result was the detection of a context effect by the discriminability measure, an effect not detected by the RT data alone. The discriminability measures yielded a near perfect correlation with estimates of the mean step size of the random walk obtained by application of the parameter estimation program FITTRW (Heath, 1983).     

A random-walk model of accuracy and reaction time applied to three experiments on pigeon visual discrimination

A random-walk model of visual discrimination is described and applied to reaction time (RT) distributions from three discrete-trial experiments with pigeons. Experiment 1 was a two-choice hue discrimination task with multiple hues. Choice percentages changed with hue discriminability; RTs were shortest for the least and most discriminable stimuli. Experiments 2 and 3 used go/no-go hue discriminations. Blocks of sessions differed in reward probability associated with a variable red stimulus in Experiment 2 and with a constant green stimulus in Experiment 3. Changes in hue had a large effect on response percentage and a small effect on RT; changes in reward shifted RT distributions on the time axis. The "random-walk, pigeon" model applied to these data is closely related to Ratcliff's diffusion model (Ratcliff, 1978; Ratcliff & Rouder, 1998). Simulations showed that stimulus discriminability affected the speed with which evidence accumulated toward a response threshold, in line with comparable effects in human subjects. Reward probability affected bias, modeled as the amount of evidence needed to reach one threshold rather than the other. The effects of reward probability are novel, and their isolation from stimulus effects within the decision process can guide development of a broader model of discrimination.     

Inhibition from semantically related primes: Evidence of a category-specific inhibition

The phenomenon of inhibition from generating successive items within a category, reported by A. S. Brown (1981), was examined in two experiments. Subjects responded on target trials by either generating targets (e.g., generating BASS to B when it followed the category name FISH, Experiment 1) or reading them (reading BASS when it followed the category name FISH, Experiment 2). Prior to target trials, all subjects received priming trials consisting of either one or four exemplars from a single semantic category, which could be either the same category as the target’s category (related priming condition) or an unrelated category (unrelated priming condition). In both experiments, different groups of subjects either read or generated primes. When primes were read, target response times (RTs) were always facilitated in the related priming condition compared with in the unrelated priming condition. However, when primes were generated, this facilitation from related primes was eliminated, except in the one-prime condition, when targets were also generated. When primes and targets were both generated, RTs in the related priming condition were slower following four primes than following one prime. Thus, category-specific inhibition from multiple related primes is greatest when both primes and targets must be actively retrieved.     

Aging and the use of advance probability information

Two experiments were performed to investigate the relation between age and use of advance probability information to prepare for a simple response. In both, an occasional presignal occurring about.5 sec before a possible response signal informed the subject that the probability of a response signal had increased from.1 to.5 In experiment 1, 24 women and men selected for short RT were tested, all between 21 and 78 yr of age. Subjects under 50 were able to use the advance information to shorten their RTs as were the majority of older subjects. However, for some older subjects the presignal produced a negative effect, a paradoxical lengthening of RT. In Experiment 2, using five of the older subjects from Experiment 1, more intensive testing was done with closer spacing of trials. Subjects who previously showed a lengthening of RT with the presignal now showed the typical shortening. In summary, over the age span investigated, almost all selected older subjects as well as younger subjects.     

Redundancy gains and coactivation with two different targets: The problem of target preferences and the effects of display frequency

When a visual display contains two targets, both of which require the same response, reaction times (RTs) are faster than when only one target appears. This effect has previously been obtained regardless of whether the redundant targets are the same or different in shape, and in at least one set of two-target experiments, the redundancy gains have been larger for different targets (Grice & Reed, 1992). Experiments with two different targets have also revealed violations of the race-model inequality, suggesting that redundant targets coactivate the response (Miller, 1982). The present paper reexamines both of these findings, because both appear to be inconsistent with the interactive race model (Mordkoff & Yantis, 1991). Experiment 1 shows that the race-model inequality is not violated when the experimental design is free of biased contingencies; Experiment 1 also provides evidence that target preferences may artifactually produce the RT advantage fordifferent- oversame-target trials. Experiment 2, however, shows that the race-model inequality is violated when the frequencies of single- and redundant-target displays are equated (without introducing any biased contingencies), implying that the interactive race model cannot account for the results of experiments involving more than one type of target. Alternative loci for coactivation are briefly discussed.     

Timing and the control of variation

Two rat experiments shed light on how variation in behavior is regulated. Experiment 1 used the peak procedure. On most trials, the 1st bar press more than 40 s after signal onset ended the signal and produced food. Other trials lasted much longer and ended without food. On those trials, the variability of bar-press duration increased greatly after the 1st response more than 40 s after signal onset. In Experiment 2, which asked whether the increase was due to the omission of expected reward or the decrease in reward expectation, reward expectation had a strong effect on response duration, whereas omission of expected reward had little effect. In both experiments, response rate and response duration changed independently, suggesting that they reflect different parts of the underlying mechanism. In Experiment 1, response durations implied that timing of the signal was more accurate than the rate-vs.-time function might suggest. Experiment 2 suggested that lowering reward expectation increases variation in response form.     

试次历史对跨通道非空间返回抑制的影响

个体对刺激的反应不仅受刺激本身的影响, 还会受到先前刺激的影响, 表现为对当前试次中刺激的反应会受到前一试次的影响, 即试次历史。本研究采用“线索-中性线索-靶子”范式探讨前一试次有效性对跨通道的非空间返回抑制的影响。实验1通过连续两个试次间的线索有效性考察在跨通道非空间返回抑制中试次历史的影响。为了在跨通道非空间返回抑制中减小试次历史的影响, 实验2通过延长试次间时间间隔考察跨通道非空间返回抑制中试次历史的作用是否减小。结果发现, 前一试次线索无效时, 当前试次中的返回抑制效应量显著小于前一试次有效时, 这种影响会根据试次中线索和靶子通道的不同而不同。并且当延长试次间的时间间隔可以有效地减少前一试次对当前试次的影响。因此本研究表明, 试次历史能够对跨通道非空间返回抑制产生影响, 并且这种影响可以通过增大试次间时间间隔来减小。     

Inhibition of return for expected and unexpected targets

Inhibition of return (IOR) refers to slower reaction times (RTs) to targets that occur in the same, rather than in a different, location as a preceding onset cue. The present study examined IOR for expected (likely) and unexpected (unlikely) targets under conditions in which stimulus-response (S-R) expectancies were generated on a trial-by-trial basis or maintained across a block of trials. Three boxes were aligned along the vertical midline. In Experiments 1 and 2, the appearance of a cue in the upper or lower box was a signal to generate an expectancy about the most likely color of an impending discrimination target. In Experiment 3, one target color was more likely than another across a block of trials. In all cases, cue location did not predict target location. When S-R expectancies were generated on a trial-by-trial basis, IOR occurred for Unlikely targets but not for Likely targets; this was true across a range of cue-target stimulus onset asynchronies. In contrast, when S-R expectancies were maintained over a block of trials, IOR was larger for Likely than for Unlikely targets. These findings reveal a critical interaction of S-R expectancies with IOR. This interaction not only demonstrates the modulation of IOR by cognitive expectancies, but in doing so also provides evidence that is consistent with the view that IOR reflects a conservative response bias.     

The "short-long" reaction time effect in duration programming

The programming processes concerned with response duration were studied in a precueing and in a priming reaction time (RT) paradigm. Participants had to produce a motor response of a specified duration as soon as possible after a response signal (RS) preceded by a warning signal (WS), which could deliver information on 2 response parameters (duration and effector). In Experiment I (precueing; N = 12), 3 effectors (the right hand, the left hand, or the knees) and 3 durations (.7, 2.5, or 5.5 s) were contrasted. Two responses differing in their biomechanical features were required in 2 blocks of trials: Subjects had to accurately time the duration of either a sustained button press or an interval between 2 brief presses. The RT patterns revealed a short-long effect: Shorter RTs were produced before the short duration than before the longer, provided that the duration was not precued. This short-long effect occurred whatever type of response and effector were involved. Two conclusions were reached. First, response duration was included in the motor program elaborated before execution, whatever the biomechanical features of the response; and, second, the program for the short duration was activated on all trials and was used as a basis for programming longer durations when needed. These conclusions were tested in Experiment 2 (priming; N = 12), in which a small proportion of invalid trials concerning duration was provided. Thus, the duration required by the RS differed from that primed by the WS. Two durations (.7 or 2.5 s) and 2 effectors (the index or the middle finger) were involved. In the invalid trials, the responses of short and long durations did not yield any RT differences, thus confirming the particular status of the short duration. This suggests that deprogramming operations (which lengthen the RT) are needed after a RS to produce short response durations but not after a RS to produce long response durations in the invalid trials.