Signal identification: The comparison of two competitive theories

Attention, Perception, & Psychophysics - On each of a series of random trials, 10 observers had to identify which of two possible tones of different amplitude had been presented. Two theories...     

Evoking shame and guilt: a comparison of two theories

Self-discrepancy theory associates shame with deviations from ideals that significant others hold for us and guilt with deviations from one's own moral guides. By contrast, Tangney posits that, although transgressions may engender both of these emotions, the nature of focus determines the specific reaction. Focusing upon the action committed engenders guilt, whereas focusing on the self who committed the action engenders shame. Participants recounted one of four types of discrepant actions and responded to measures of shame, guilt, anxiety, and depression. Consistent with Tangney's theorizing, across all types of discrepant actions, guilt was rated significantly higher than shame.     

Contrasting five different theories of letter position coding: evidence from orthographic similarity effects

Five theories of how letter position is coded are contrasted: position-specific slot-coding, Wickelcoding, open-bigram coding (discrete and continuous), and spatial coding. These theories make different predictions regarding the relative similarity of three different types of pairs of letter strings: substitution neighbors, neighbors-once-removed, and double-substitution neighbors. In Experiment 1, we used an illusory word paradigm and found that neighbor-once-removed similarity contexts resulted in fewer illusory word reports than substitution neighbors but more illusory words than double-substitution neighbors. In Experiments 2 and 3, we used a masked form priming technique with a lexical-decision task. The pattern of facilitation was as predicted by spatial coding but was incompatible with slot-coding, Wickelcoding, and both versions of open-bigram coding. These results provide further support for the SOLAR (self-organizing lexical aquisition and recognition) model of visual word identification.     

Contextual control of letter perception

This study examined the hypothesis that the type of list context in which a given item is embedded may affect the way in which it is perceptually processed. In the first experiment, subjects matched four types of test items inserted in four types of lists. The types of test items and the types of lists in which they were embedded were two-letter words, two-letter spelling clusters, unrelated letter pairs, and pairs of novel letters. The first experiment indicated that only unrelated letter pairs were significantly affected by type of list in which they were inserted. The pattern of the effect was confirmed in the latency data of the second experiment and the interpretation was that only unrelated letter and related letter-group contexts were operating in the first two experiments. The third and fourth experiments were concerned with contrasting contexts at the feature and letter levels of processing. By using lists in which type of catch trial either emphasized local features or global aspects of a pattern, the processing times of both familiar and unfamiliar letters were affected. The results of these experiments suggest that information processing models should incorporate structures which represent the way that context selectively facilitates processing of items at particular levels.     

Age differences in peripheral letter perception

The capacities of 96 eight- and nine-year-old children and 96 adults to discriminate letters in the visual periphery were tested. Four-letter arrays were presented at the fixation point or centered 4 degrees to the left or right. Threshold exposure durations were estimated by a method of ascending limits. Analyses of a transformed threshold measure revealed that although children were less able than adults to discriminate letters in all positions, age differences were greatest for peripherally presented arrays. Development specific to the peripheral visual systems seems implicated.     

Lexically guided retuning of letter perception

Participants made visual lexical decisions to upper-case words and nonwords, and then categorized an ambiguous N-H letter continuum. The lexical decision phase included different exposure conditions: Some participants saw an ambiguous letter "?", midway between N and H, in N-biased lexical contexts (e.g., REIG?), plus words with unambiguous H (e.g., WEIGH); others saw the reverse (e.g., WEIG?, REIGN). The first group categorized more of the test continuum as N than did the second group. Control groups, who saw "?" in nonword contexts (e.g., SMIG?), plus either of the unambiguous word sets (e.g., WEIGH or REIGN), showed no such subsequent effects. Perceptual learning about ambiguous letters therefore appears to be based on lexical knowledge, just as in an analogous speech experiment (Norris, McQueen, & Cutler, 2003) which showed similar lexical influence in learning about ambiguous phonemes. We argue that lexically guided learning is an efficient general strategy available for exploitation by different specific perceptual tasks.     

Lexically guided retuning of letter perception

Participants made visual lexical decisions to upper-case words and nonwords, and then categorized an ambiguous N–H letter continuum. The lexical decision phase included different exposure conditions: Some participants saw an ambiguous letter “?”, midway between N and H, in N-biased lexical contexts (e.g., REIG?), plus words with unambiguous H (e.g., WEIGH); others saw the reverse (e.g., WEIG?, REIGN). The first group categorized more of the test continuum as N than did the second group. Control groups, who saw “?” in nonword contexts (e.g., SMIG?), plus either of the unambiguous word sets (e.g., WEIGH or REIGN), showed no such subsequent effects. Perceptual learning about ambiguous letters therefore appears to be based on lexical knowledge, just as in an analogous speech experiment (Norris, McQueen, & Cutler, 2003) which showed similar lexical influence in learning about ambiguous phonemes. We argue that lexically guided learning is an efficient general strategy available for exploitation by different specific perceptual tasks.     

Masked partial priming of letter perception

In three experiments testing 178 subjects, letter targets were preceded by briefly presented, pattern-masked primes formed by deleting pixels in a larger or smaller version of the target stimulus. In Experiment 1A (alphabetic decision)and Experiment 1B (letter naming) a slight advantage was observed for global primes (alternate pixels deleted) compared with junction primes (midsegment information removed). This advantage was stronger at 50 ms prime exposures than at 30 ms exposures in the naming task. In Experiment 2 (letter naming), midsegment primes (with junction information removed) produced faster latencies than did junction primes. This result was replicated in a third experiment and was shown to be independent of target letter case and the relative size of prime and target stimuli. The same midsegment and junction primes did not facilitate performance compared to neutral primes in the alphabetic decision task. These results suggest that masked partial priming of letter naming can be usefully applied to the study of basic processes in letter perception.     

Types and tokens in visual letter perception

Five experiments demonstrate that in briefly presented displays, subjects have difficulty distinguishing repeated instances of a letter or digit (multiple tokens of the same type). When subjects were asked to estimate the numerosity of a display, reports were lower for displays containing repeated letters, for example, DDDD, than for displays containing distinct letters, for example, NRVT. This homogeneity effect depends on the common visual form of adjacent letters. A distinct homogeneity effect, one that depends on the repetition of abstract letter identities, was also found: When subjects were asked to report the number of As and Es in a display, performance was poorer on displays containing two instances of a target letter, one appearing in uppercase and the other in lowercase, than on displays containing one of each target letter. This effect must be due to the repetition of identities, because visual form is not repeated in these mixed-case displays. Further experiments showed that this effect was not influenced by the context surrounding the target letters, and that it can be tied to limitations in attentional processing. The results are interpreted in terms of a model in which parallel encoding processes are capable of automatically analyzing information from several regions of the visual field simultaneously, but fail to accurately encode location information. The resulting representation is thus insufficient to distinguish one token from another because two tokens of a given type differ only in location. However, with serial attentional processing multiple tokens can be kept distinct, pointing to yet another limit on the ability to process visual information in parallel.     

Context effects in two-month-old infants' perception of labiodental/interdental fricative contrasts

We investigated 2-month-old infants' perception of a subset of highly confusable English fricatives. In Experiment 1, infants discriminated modified natural tokens of the voiceless fricative pair [fa]/[oa] but only when the syllables included their frication noises. They also discriminated the voiced pair [va]/[oa] both with and without fricative noises. These results parallel those found with adults by Carden, Levitt, Jusczyk, and Walley (1981). In Experiment 2 [f] and [o] noises were appended to [a], and the same [f] noise was appended to the previously indiscriminable fricationless versions of [fa] and [oa]. Infants discriminated both pairs of stimuli, indicating that (a) the frication is a sufficient cue for [fa]/[oa] discrimination and that (b) it provides a context for discriminating the [f] and [o] formant transitions. We conclude that infants' perception of labiodental/interdental fricative contrasts show evidence of context effects similar to those observed with adults.     

Contextual effects in vowel perception II: Evidence for two processing mechanisms

Recent experiments have indicated that contrast effects can be obtained with vowels by anchoring a test series with one of the endpoint vowels. These contextual effects cannot be attributed to feature detector fatigue or to the induction of an overt response bias. In the present studies, anchored ABX discrimination functions and signal detection analyses of identification data (before and after anchoring) for an [i]-[I] vowel series were used to demonstrate that [i] and [I] anchoring produce contrast effects by affecting different perceptual mechanisms. The effects of [i] anchoring were to increase within-[i] category sensitivity, while [I] anchoring shifted criterion placements. When vowels were placed in CVC syllables to reduce available auditory memory, there was a significant decrease in the size of the [I]-anchor contrast effects. The magnitude of the [i]-anchor effect was unaffected by the reduction in vowel information available in auditory memory. These results suggest that [i] and [I] anchors affect mechanisms at different levels of processing. The [i] anchoring results may reflect normalization processes in speech perception that operate at an early level of perceptual processing, while the [I] anchoring results represent changes in response criterion mediated by auditory memory for vowel information.     

Context effects in visual length perception: role of ocular,retinal, and spatial location

In three experiments, we examined the transfer of orientation-contingent context effects between the eyes and across portions of the retina with or without variation in external spatial location. Previous research had shown that vertical lines are judged long, relative to horizontal lines, when the stimulus set comprises relatively long horizontals and short verticals (Contextual Condition B), as compared with the reverse when the stimulus set comprises relatively short horizontals and long verticals (Contextual Condition A). Consequently, the contextual set of stimuli influences the magnitude of the horizontal-vertical illusion (HVI), decreasing its size under Contextual Condition A and increasing its size under Contextual Condition B. Experiment 1 showed that exposing one eye to different stimulus contexts modulated the size of the HVI at the exposed eye but had little or no effect at the other eye. Experiments 2 and 3 showed that the effect of the contextual sets generalized poorly across adjacent portions of the retina but transferred almost perfectly across different locations in external space when retinal location was constant. Thus, orientation-contingent context effects in visual length perception appear to be specific to the eye and to the region of the retina stimulated, suggesting that these effects reflect relatively early and local changes in sensitivity, rather than relatively late and general shifts in response criteria.     

Semantic congruity effects and theories of the comparison process.

Two experiments requiring comparisons of point locations on the line demonstrate that the magnitude of the response-time-based congruity effect parallels the form of the macro and the micro speed-accuracy trade-off function. This is predicted from the evidence accrual class of theories but is contrary to either the propositionally based semantic coding theory or the expectancy view. Very large accuracy-based congruity effects with comparisons of point locations in the plane are evident. Congruity effects arise because the duration of each evidence accrual is increased and the quality of the information is reduced as the distance of the stimulus representations from the instruction-activated reference point increases. This evidence accrual view is extended to account for the properties of perceptual and symbolic comparisons.     

Judgments of moderator variables of agreement in person perception: A comparison of two cultures

Three moderators of agreement in person perception, behavioral consistency, observability and social desirability, were studied. The major hypothesis is that the moderators can be estimated using the standing of targets on traits; that is, that as targets vary on a given trait, they vary on how they are seen as on the moderators. Using Korean ( N  = 135) and US ( N  = 81) samples, we tested this approach for 80 traits. Analyses revealed that moderators varied by the combination of trait and target standing in different ways for the two samples. In judgment of behavioral consistency over target standings, linear and curvilinear trends were stronger for the US sample than for the Korean sample. For observability, judgments were similar, although curvilinear trends were larger for the Korean sample. Furthermore, being extremely positive was perceived as less desirable for the Korean judges. These findings were discussed in terms of cultural differences. Moreover, a new approach to the study of moderators was proposed.