Effects of stimulus duration and inter-letter spacing on letter-in-string identification

Effects of stimulus duration and inter-letter spacing were studied in a letter-in-string identification paradigm. Participants were shown strings of 5 random consonants (e.g., PGKDM) centered on fixation and were asked to identify the letter that had appeared at a post-cued location. Stimulus duration was manipulated in Experiment 1 (13 ms–91 ms), and inter-letter spacing manipulated in Experiment 2 (for a fixed stimulus duration of 26 ms). We contrasted performance to outer-letters (positions 1 and 5) with non-central inner letters (positions 2 and 4), the first-letter (position 1) with the final letter (position 5), and the central-letter (position 3) with the other inner letters (positions 2 and 4). The outer-letter advantage and the first-letter advantage were present throughout the entire range of exposure durations, whereas the central-letter advantage increased with longer exposures. On the other hand, increased spacing reduced both the outer-letter advantage and the first-letter advantage, whereas it led to a greater central-letter advantage. Changes in acuity and crowding as a function of stimulus exposure and inter-letter spacing, can account for this pattern of results.     

Effects of time-order, interstimulus interval, and feedback in duration discrimination of noise bursts in the 50- and 1000-ms ranges

Participants compared durations of paired white-noise bursts, with interstimulus interval (ISI) 100, 300, 900, or 2700 ms, presented in the order standard (St)-comparison (Co) or Co-St. St was 50 or 1000 ms, and 75% difference thresholds for "longer" and "shorter" judgments were estimated. In Experiment 1 feedback was given; in Experiment 2, with ISIs 900 and 2700 ms, there was no feedback. For St=1000 ms, the just noticeable difference (JND) in noise duration was generally smaller with the order St-Co than with Co-St; for St=50 ms, the JND relation was the opposite. JNDs increased with shorter ISIs. Time-order errors were positive for St=50 ms and negative for St=1000 ms, and approached zero for longer ISIs. Using Hellstr?m's sensation-weighting (SW) model, the ratio of the stimulus weights for the first and second burst was estimated; this ratio was generally >1 for St=50 ms and <1 for St=1000 ms. JNDs were smaller with feedback than without; the greatest reduction was found for St=1000 ms and an ISI of 2700 ms with the order Co-St, possibly because feedback increased participants' attention to the first stimulus. These results demonstrate the sensitivity of discrimination measures for long as well as brief durations to the factors of ISI, presentation order, and feedback. They also suggest different modes of stimulus processing for short and long durations.     

Introspective duration estimation of reactive and proactive motor responses

The metajudgment of motor responses refers to our ability to evaluate the accuracy of our own actions. Can humans metajudge the duration of their Reaction Times (RTs) to a light-flash and the accuracy of their reproduction of a reference time interval bounded by two light flashes (Anticipatory Response Time, ART)? A series of four distinct experiments shows that RT_Meta and ART_Metajudgments are possible but with accuracies about ×2.4 and ×3 poorer than the corresponding RT and ART ones. In order to reveal the origin of this drop in performance, we ask whether a visual feedback synchronous with subjects’ key-presses could improve performance. We show that overall the presence of a visual feedback does not significantly improve metajudgment accuracy although such a trend is noticeable in ART_Meta. We then compare these performances with the passive perceptual estimation of the played back (Pb) RT and ART time intervals when bounded by two (RT_Pb) and three (ART_Pb) light flashes. We show that RT_Meta and RT_Pb accuracies are close to equal, but that ART_Meta is about ×2 less accurate than ART_Pb which in turn is ×1.5 less accurate than ART. The latter observation fails however to reach statistical significance hence not sustaining proposals that active time estimation is more reliable than passive one. The whole dataset is accounted for by a clock-type model where duration estimation performance is limited by four noise sources (visual, clock-count, motor and proprioceptive + efference copy) plus one proper to ART_Meta task. It is proposed that the latter reflects the impossibility for the time-counting system to use the same time origin more than once.     

The effects of verbal cueing on implicit hand maps

The use of position sense to perceive the external spatial location of the body requires that immediate proprioceptive afferent signals be combined with stored representations of body size and shape. Longo and Haggard (2010) developed a method to isolate and measure this representation in which participants judge the location of several landmarks on their occluded hand. The relative location of judgements is used to construct a perceptual map of hand shape. Studies using this paradigm have revealed large, and highly stereotyped, distortions of the hand, which is represented as wider than it actually is and with shortened fingers. Previous studies using this paradigm have cued participants to respond by giving verbal labels of the knuckles and fingertips. A recent study has shown differential effects of verbal and tactile cueing of localisation judgements about bodily landmarks (Cardinali et al., 2011). The present study therefore investigated implicit hand maps measuring through localisation judgements made in response to verbal labels and tactile stimuli applied to the same landmarks. The characteristic set of distortions of hand size and shape were clearly apparent in both conditions, indicating that the distortions reported previously are not an artefact of the use of verbal cues. However, there were also differences in the magnitude of distortions between conditions, suggesting that the use of verbal cues may alter the representation of the body underlying position sense.     

Assessment of calibration for reconstructed eye-witness memories

Two experiments examined confidence judgments associated with eyewitness memory for events to misinformation [Loftus, E. F. (1975). Leading questions and the eyewitness report. Cognitive Psychology, 7, 560-572]. Participants in each experiment watched videos depicting crimes and either responded to questionnaires (Experiment 1) or read narratives (Experiment 2) containing veridical or non-veridical information. Upon testing for memory performance 24 h later, participants exposed to misinformation accepted the misinformation as part of their memory of the events in the videos. In both experiments, confidence judgments of participants subjected to misinformation were high and comparable to those of participants not subjected to misinformation. The relationship between accurate responding and confidence was assessed via calibration analysis [Yates, J. F. (1990). Judgments and decision making. Englewood Cliffs, NJ: Prentice Hall]. Performance on various measures of calibration was generally better for participants who were not exposed to misinformation. We conclude that confidence judgments can depend on factors other than those that improve the accuracy of memory, such as the retrieval fluency of one’s memories.     

Differential involvement of internal clock and working memory in the production and reproduction of duration: a study on older adults

The present study uses the inter-individual variability in time perception of a group of elderly participants to differentiate the processes underlying time production and time reproduction. Participants performed duration production and reproduction tasks. They were also administered working memory tests and a spontaneous motor tempo task. The findings suggest that duration production and duration reproduction involve different mechanisms. Correlational analyses revealed a double dissociation: production was only correlated with spontaneous motor tempo and reproduction only with working memory measures. These findings suggest that the internal clock rate modulates the production of duration and that reproduced duration varies according to working memory capacities.     

The embodied cognition theory and the motor component of “yes” and “no” verbal responses

Most of the experiments which give theories of embodied cognition their empirical anchorage only take into consideration the motor responses induced by the task or the motor component of the visual stimulus. And yet, these motor responses are often associated with a linguistic answer. Our hypothesis is that “YES” and “NO” verbal responses have a motor component. In a first experiment we showed that producing a verbal response (YES vs. NO) involves motor planning (pushing vs. pulling): participants push a lever more quickly when they have to answer “yes” than “no”, and conversely, they pull a lever more quickly when they have to answer “no” than “yes”. Moreover, in a second experiment, we showed that perceiving the words “YES” and “NO”, on its own, leads to the same motor planning than when “yes” and “no” answers actually have to be produced. Participants detect the word “YES” faster when they have to push a lever than when they have to pull it and conversely they detect the word “NO” faster when they have to pull the lever than when they have to push it down. These results are discussed in reference to “online” and “offline embodiment” concepts and to the cognitive linguistic theories.     

Sex differences in recollective experience for olfactory and verbal information

We examined recollective experience as a function of sex for olfactory and verbal information. In the first study, men and women studied a set of highly familiar odors with incidental or intentional encoding instructions. In the second study, participants were presented with a number of sentences. At recognition, participants indicated whether their positive response was based on conscious recollection (remembering), a feeling of familiarity (knowing), or guessing. The results indicated that recollection was higher among women than men, and that familiarity-based recognition was equally large across sex for both types of information.The finding that the sex-related experiential difference disappeared when controlling for verbal proficiency suggests that sex-related differences in activating verbal information play an important role for sex differences in recollective experience.     

Children's verbal working memory: relative importance of storage, general processing speed, and domain-general controlled attention

This study evaluated multiple constraints of verbal working memory in typically developing 7- to 11-year-olds. Multiple measures of verbal working memory and the predictors-short-term memory storage, general speed, and domain-general controlled attention were used. General linear modeling (GLM) showed that storage and the efficiency of controlled attention (i.e., speed of updating information during attention switching) contributed to significant variance in children's verbal working memory. In a secondary analysis verbal storage and domain-general attention (focus switching accuracy and speed of updating on switch) emerged as significant predictors. Results suggest domain-general attention and verbal storage mechanisms to be independent constraints of verbal working memory.     

Stimulus spacing effects in duration perception are larger for auditory stimuli: Data and a model

Models of duration bisection have focused on the effects of stimulus spacing and stimulus modality. However, interactions between stimulus spacing and stimulus modality have not been examined systematically. Two duration bisection experiments that address this issue are reported. Experiment 1 showed that stimulus spacing influenced the classification of auditory, but not visual, stimuli. Experiment 2 used a wider stimulus range, and showed stimulus spacing effects for both visual and auditory stimuli, although the effects were larger for auditory stimuli. A version of Temporal Range Frequency Theory was applied to the data, and was used to demonstrate that the qualitative pattern of results can be captured with the single assumption that the durations of visual stimuli are less discriminable from one another than are the durations of auditory stimuli.     

Effects of processing fluency on comparative performance judgments

Research has shown that performance predictions are biased by the impact of processing fluency. However, existing data are inconclusive with regard to comparative judgments of performance. In five experiments, participants in an easy condition gave more favorable comparative judgments than participants in a difficult condition. Participants judged their performance more favorably if they named colors of non-color words rather than non-matching color words (Experiment 1), if they had to generate six words of a category rather than 12 words (Experiment 2), if they had to run in place for 15 s rather than 2 min (Experiment 3), but the latter result holds only true if participants were not active in sports (Experiment 4). When 67% of the items in a recognition test were old words, participants thought that their recognition performance was better than when 33% of the items were old words, although recognition performance did not differ between groups (Experiment 5). We discuss this result in the light of recent theories about effects of processing fluency on judgments.     

Glimpses of a one-speed mind: Focus-switching and search for verbal and visual, and easy and difficult items in working memory

We investigated focus-switching and search rates in an N-Back task for stimuli presumably encoded either in a phonological/semantic or an abstract-visual format. Experiment 1 used Chinese characters and tested Chinese speakers and non-Chinese speakers; character frequency and visual complexity were also manipulated. Experiment 2 presented Chinese characters and English words to non-Chinese English speakers. Effects of focus-switching on accuracy were larger for abstract-visual stimuli and for more difficult stimuli; effects on RT were larger for abstract-visual stimuli, but there was no effect of difficulty, with the exception of the most difficult stimulus set in Experiment 1. Search slopes outside the focus of attention did not covary with either type of code or item difficulty. The decline in accuracy over set-size was stronger for the items coded in abstract-visual format. This suggests that item availability is sensitive to robustness of the memory representations, but item accessibility is not. The data fit well with a model of STM in which a fixed number of ‘slots’ are searched at a constant rate, regardless of the slot’s contents.     

The effect of phonological realization of inflectional morphology on verbal agreement in French: evidence from ERPs

The present study examined the impact of the phonological realization of morphosyntactic agreement within the inflectional phrase (IP) in written French, as revealed by ERPs. In two independent experiments, we varied the presence vs. absence of phonological cues to morphological variation. Of interest was whether a graded ERP response to these different conditions could be found in native speakers (Experiment 1), and whether non-native learners would benefit from the presence of phonological cues (Experiment 2). The results for native French speakers showed that compared to grammatically correct instances, phonologically realized inflectional errors produced a significant P600 response, which was statistically larger than that produced by errors that were silent. German L1-French L2 learners showed similar benefits of the phonological realization of morphemes. Phonologically realized errors produced a robust P600 response whereas silent errors produced no robust effects. Implications of these results are discussed in reference to previous studies of L2 acquisition of morphosyntax.     

Manipulability impairs association-memory: Revisiting effects of incidental motor processing on verbal paired-associates

Imageability is known to enhance association-memory for verbal paired-associates. High-imageability words can be further subdivided by manipulability, the ease by which the named object can be functionally interacted with. Prior studies suggest that motor processing enhances item-memory, but impairs association-memory. However, these studies used action verbs and concrete nouns as the high- and low-manipulability words, respectively, confounding manipulability with word class. Recent findings demonstrated that nouns can serve as both high- and low-manipulability words (e.g., CAMERA and TABLE, respectively), allowing us to avoid this confound. Here participants studied pairs of words that consisted of all possible pairings of high- and low-manipulability words and were tested with immediate cued recall. Recall was worse for pairs that contained high-manipulability words. In free recall, participants recalled more high- than low-manipulability words. Our results provide further evidence that manipulability influences memory, likely occurring through automatic motor imagery.     

Effect of short and long exposure duration and dual-tasking on a global-local task

Past research has demonstrated a global advantage in responses to visually presented hierarchical stimuli such that, on incongruent trials, the global form interferes with responses to the local level [Kimchi, R. (1992). Primacy of wholistic processing and global/local paradigm: A critical review. Psychological Bulletin, 112, 24-38]. In Experiment 1, 32 adults performed alternating blocks of global or local identification of hierarchical letter stimuli in which the global and local letters were congruent, incongruent, or neutral, and were presented at either a short (17 ms) or long (100 ms) exposure duration. A global advantage was demonstrated at both durations. In the local-directed task, interference on incongruent, relative to neutral, trials was observed at both exposure durations, but facilitation on congruent trials, relative to neutral trials, was present only when stimuli were presented at the long exposure duration. In Experiment 2, global or local identification was performed by another group of 24 adults at either a long or short exposure duration, and also under conditions of full attention (FA) or dual-task (DT) conditions with a digit-monitoring task. Under FA, we again found significant interference at both exposure durations, but facilitation only at the long exposure duration. Under DT conditions, the pattern of facilitation and interference at the short duration remained unchanged. At the long duration, however, dual-tasking eliminated interference in the RT but not error data, while facilitation was present in both sets of data. Results are in line with a perceptual account of the global advantage, and suggest that facilitation requires consciously-mediated processes, whereas interference does not.     

A feature-based inference model of numerical estimation: The split-seed effect

Prior research has identified two modes of quantitative estimation: numerical retrieval and ordinal conversion. In this paper we introduce a third mode, which operates by a feature-based inference process. In contrast to prior research, the results of three experiments demonstrate that people estimate automobile prices by combining metric information associated with two critical features: product class and brand status. In addition, Experiments 2 and 3 demonstrated that when participants are seeded with the actual current base price of one of the to-be-estimated vehicles, they respond by revising the general metric and splitting the information carried by the seed between the two critical features. As a result, the degree of post-seeding revision is directly related to the number of these features that the seed and the transfer items have in common. The paper concludes with a general discussion of the practical and theoretical implications of our findings.     

I saw it for longer than you: the relationship between perceived encoding duration and memory conformity

The memory conformity effect is when people's memories become similar to one another's following a discussion. The present study examined whether an individual's beliefs in the quality of their memory, relative to another person's, mediates susceptibility to memory conformity. Perceived encoding duration was manipulated by telling dyad members that one person had encoded a set of pictures for either half or twice as long as their partner. In fact, actual encoding duration was the same for all participants. Dyad members each encoded slightly different versions of otherwise identical pictures and discussed them prior to an individual free recall test. Participants who believed that they had encoded the pictures for half as long as their partner were more susceptible to memory conformity, as indicated by their increased tendency to report errant items at test that had been encountered from their partner rather than items that they had actually seen. This effect of perceived encoding duration on memory conformity was mediated through response order. A source monitoring test found that these unseen items were errantly attributed to the pictures approximately 50% of the time. The findings are discussed in relation to the role of metamemory in susceptibility to memory conformity.     

Effects of relative embodiment in lexical and semantic processing of verbs

Research examining semantic richness effects in visual word recognition has shown that multiple dimensions of meaning are activated in the process of word recognition (e.g., Yap et al., 2012). This research has, however, been limited to nouns. In the present research we extended the semantic richness approach to verb stimuli in order to investigate how verb meanings are represented. We characterized a dimension of relative embodiment for verbs, based on the bodily sense described by Borghi and Cimatti (2010), and collected ratings on that dimension for 687 English verbs. The relative embodiment ratings revealed that bodily experience was judged to be more important to the meanings of some verbs (e.g., dance, breathe) than to others (e.g., evaporate, expect). We then tested the effects of relative embodiment and imageability on verb processing in lexical decision (Experiment 1), action picture naming (Experiment 2), and syntactic classification (Experiment 3). In all three experiments results showed facilitatory effects of relative embodiment, but not imageability: latencies were faster for relatively more embodied verbs, even after several other lexical variables were controlled. The results suggest that relative embodiment is an important aspect of verb meaning, and that the semantic richness approach holds promise as a strategy for investigating other aspects of verb meaning.