Tadashi Kikuchi

Span of attention, backward masking, and reaction time

A test pattern consisting of 0 to 15 dots and a following random dot masking pattern were presented for 5 msec each with SOAs varying between 30 and 200 msec. The subject was asked to report the perceived number of dots in the test pattern as soon as possible and to assign a confidence rating to each report. The span of attention (upper limit for 50% correct numerosity judgments) increased from 2.4 to 9.5 as the SOA increased. Backward masking reduced the reported number of dots from the actual number in the test pattern, especially with small SOAs. Reaction time increased linearly at a low rate (approximately 40 msec/dot) up to 4 dots in the test pattern and then increased linearly at a high rate (approximately 370 msec/dot) as thereported, orperceived, number of dots increased. The two different branches of the reaction time curve were considered to represent two separate processes,subitizing andcounting, as suggested by Klahr (1973), who found similar dual increase rates as a function of the actual number of dots. These findings, as well as causal inference based on partial correlations and path analysis, indicated that the reported (perceived) number of dots and confidence rating were both determined by the number of stimulus dots and the SOA and that the reaction time was determined by the so-determined perceived number of dots and level of confidence. A multistage model is proposed.

Attentional Modulation of the Mere Exposure Effect.

The mere exposure effect refers to the phenomenon where previous exposures to stimuli increase participants subsequent affective preference for those stimuli. This study explored the effect of selective attention on the mere exposure effect. The experiments manipulated the to-be-attended drawings in the exposure period (either red or green polygons in Experiments 1 and 2; both red and green polygons in Experiments 3 and 4) and black to-be-evaluated drawings in the affective judgment period (morphologically identical to the red or green polygons in Experiments 1 and 4; morphologically identical to the composite drawings in Experiments 2 and 3). The results showed a significant mere exposure effect only for the target shapes involved in attentional selection, even when the participants could recognize the nontarget shapes. This indicates that selective attention modulated the mere exposure effect.

EFFECT OF VERBAL CUES ON RECOGNITION MEMORY AND PLEASANTNESS EVALUATION OF UNFAMILIAR ODORS

The experiment investigated the effect of verbal cues on recognition memory for unfamiliar odors. 58 participants learned 20 odors of chemical substances. The control group learned the odors without accompanying verbal labels whereas two other groups learned the odors with accompanying verbal labels. The labels referred to relatively pleasant or unpleasant odor sources. On a memory test, administered 15 min. and also 1 wk. after the learning phase, participants were asked to recognize 10 learned odors from 10 unlearned odors and to evaluate each odors pleasantness. Analysis showed (a) the verbal labels did not facilitate recognition of the unfamiliar odors, (b) recognition performance was lower after 1 wk. than after 15 min., and (c) rated pleasantness tended to be affected by the verbal label assigned to the odor in the learning phase.

Temporal characteristics of visual memory.

In order to infer the temporal relations among iconic, short-term, and long-term components of visual memory, random dot patterns were used as memory stimuli in six recognition memory experiments. Experiment 1 demonstrated that recognition was still above chance for intervals up to 12 s. In Experiments 2 and 3, an intervening masking stimulus was found to be effective only if presented within the first 500 ms of the interval. The remaining three experiments employed a two-target task, with the second target replacing the masking stimulus. Recognition performance with the second target was the same as that in a single-target task, whereas performance with the first target was almost at chance level. Increasing the interval between the targets resulted in a gradual improvement in the recognition of the first target.

Recognition of affect in facial expression using the Noh Mask Test: Comparison of individuals with schizophrenia and normal controls

Abstractu2002 The purpose of the present study was to compare facial expression recognition in individuals with schizophrenia and normal controls using the Noh Mask Test. Fifteen men with schizophrenia and 15 normal controls were presented with a photograph of a Noh mask rotated either upward or downward from the neutral front‐facing position, and an emotion label, and were requested to judge whether the expression of the mask was congruent with the indicated emotion. Using multidimensional scaling, the facial expression of the Noh mask recognized by the patients and the healthy controls was analyzed in 3‐D: (i) Rejection–Attention; (ii) Pleasant–Unpleasant; and (iii) Awakening–Relaxation. Individuals with schizophrenia had difficulty recognizing that others had intentions of harming them. The Noh Mask Test was found to be useful in discriminating between individuals with schizophrenia and controls in the recognition of facial expression (discriminant ratio: 99.9%).

Are Olfactory Images Sensory in Nature

We investigated the features of olfactory mental images by comparing odour images with perceptual and semantic representations. Participants who were assigned to three groups made similarity judgments about 17 common odours by smelling odours, imagining odours, or on the basis of the meaning of odour source names. In the smelling group, every pair of odours was compared. In the imagining group, imagined odours were compared twice, both before and after associative learning of the odour/name combinations. In the meaning group, the odour source names were compared in terms of general word meanings. Nonmetric multidimensional scaling analysis was applied to each group of similarity data and three-dimensional sensory, mental, and semantic spaces were composed. 17 elements in the mental and semantic spaces were super-imposed onto the sensory space by Procrustes rotation. We found that the averaged distances of the 17 elements between the sensory and the mental spaces (either before or after learning) were smaller than those between the sensory and semantic spaces. We suggest that odour images have sensory features, especially after associative learning between perceived odours and their names.

A facilitative effect of negative affective valence on working memory.

Previous studies have shown that negatively valenced information impaired working memory performance due to an attention-capturing effect. The present study examined whether negative valence could also facilitate working memory. Affective words (negative, neutral, positive) were used as retro-cues in a working memory task that required participants to remember colors at different spatial locations on a computer screen. Following the cue, a target detection task was used to either shift attention to a different location or keep attention at the same location as the retro-cue. Finally, participants were required to discriminate the cued color from a set of distractors. It was found that negative cues yielded shorter response times (RTs) in the attention-shift condition and longer RTs in the attention-stay condition, compared with neutral and positive cues. The results suggest that negative affective valence may enhance working memory performance (RTs), provided that attention can be disengaged.

The Noh mask test for analysis of recognition of facial expression.

A preliminary study on the Noh mask test for analysis of recognition of facial expression was performed. The present study was conducted on 15 normal subjects (mean age: 32 years, SD 9.7 years) as the first step to test for the differences between psychiatric patients and normal subjects. Stimuli were created by photographs of 15 Noh masks at different vertical angles. Subjects were given 12 tasks (12 emotion items), and each task consisted of 15 trials (15 Noh mask images). In each trial, the subject viewed a colour monitor, and was shown an emotion item, followed by a Noh mask image. The subject pressed either the yes or no key to indicate whether the Noh mask image expressed the emotion item. The subject’s response and reaction time to each Noh mask image showed no deviation, although the subject’s response and reaction time to each emotion item showed some deviation. As the vertical angle of the Noh mask changed, normal subjects recognized all emotion items except the ‘uncanny’ expression. Factor analysis of the 15 Noh mask images produced three factors, and the analysis of 12 emotion items produced five factors. Thus, the Noh mask test was simplified to nine images and nine items. Further developments of the Noh mask test may include the evaluation of the dysfunction of perception on delicate facial expression in psychiatric patients.

DETECTION OF KANJI WORDS IN A RAPID SERIAL VISUAL PRESENTATION TASK

In 3 experiments, lists of 12 Kanji words were rapidly presented in the same position, and participants reported a red target word embedded in green distractor words. Two lists were used: same and different category. A tendency toward category priming was found at longer durations. Frequency of target localization indicated that participants familiar with Kanji had a greater tendency to report the word immediately preceding the target. These pretarget intrusion errors dominated the posttarget intrusion errors, when the luminance of red and green stimuli were equated (Experiment 2), and when the response was recall (Experiments 1 and 2) or recognition (Experiment 3). In contrast, participants unfamiliar with Kanji made posttarget intrusion errors as frequently as pretarget intrusion errors (Experiment 3), suggesting that knowledge of Kanji influences the integration of color and form codes in visual information processing.

Functional Visual Field in a Rapid Serial Visual Presentation Task

Dynamic temporal change in the size of functional visual field was measured using a dual task: a peripheral task in which one square in a background pattern of squares was changed in shape to a dot; and a central task involving the rapid serial visual presentation of a sequence of letters (RSVP task). The temporal lag between the occurrences of the dot and the RSVP target was manipulated. University students were asked to detect the dot and to depress a mouse button as quickly as possible while searching for the RSVP target among a sequence of distracter letters. The abrupt change in the shape of a background square in the peripheral task caused a processing deficit in the RSVP task at relative lags from –3 to –1 (255 ms to 85 ms before presentation of the RSVP target), but the encoding and retaining processes involved in identifying the RSVP target did not impair the detection of the peripheral dot. The functional visual field was found to expand while participants were performing the dual task, suggesting that preattentive detection is affected by general attentional activity.