Familiarity and pop-out in visual search

In this paper, we report that when the low-level features of targets and distractors are held constant, visual search performance can be strongly influenced by familiarity. In the first condition, a was the target amid as distractors, and vice versa. The response time increased steeply as a function of number of distractors (82 msec/item). When the same stimuli were rotated by 90° (the second condition), however, they became familiar patterns— and —and gave rise to much shallower search functions (31 msec/item). In the third condition, when the search was for a familiar target, (or ), among unfamiliar distractors, (or ), the slope was about 46 msec/item. In the last condition, when the search was for an unfamiliar target, (or ), among familiar distractors, s (or s), parallel search functions were found with a slope of about 1.5 msec/item. These results show that familiarity speeds visual search and that it does so principally when the distractors, not the targets, are familiar.     

Talker continuity and the use of rate information during phonetic perception

Research has shown that speaking rate provides an important context for the perception of certain acoustic properties of speech. For example, syllable duration, which varies as a function of speaking rate, has been shown to influence the perception of voice onset time (VOT) for syllableinitial stop consonants. The purpose of the present experiments was to examine the influence of syllable duration when the initial portion of the syllable was produced by one talker and the remainder of the syllable was produced by a different talker. A short-duration and a long-duration /bi/-/pi/ continuum were synthesized with pitch and formant values appropriate to a female talker. When presented to listeners for identification, these stimuli demonstrated the typical effect of syllable duration on the voicing boundary: a shorter VOT boundary for the short stimuli than for the long stimuli. An /i/ vowel, synthesized with pitch and formant values appropriate to a male talker, was added to the end of each of the short tokens, producing a new hybrid continuum. Although the overall syllable duration of the hybrid stimuli equaled the original long stimuli, they produced a VOT boundary similar to that for the short stimuli. In a second experiment, two new /i/ vowels were synthesized. One had a pitch appropriate to a female talker with formant values appropriate to a male talker; the other had a pitch appropriate to a male talker and formants appropriate to a female talker. These vowels were used to create two new hybrid continua. In a third experiment, new hybrid continua were created by using more extreme male formant values. The results of both experiments demonstrated that the hybrid tokens with a change in pitch acted like the short stimuli, whereas the tokens with a change in formants acted like the long stimuli. A fourth experiment demonstrated that listeners could hear a change in talker with both sets of hybrid tokens. These results indicate that continuity of pitch but not formant structure appears to be the critical factor in the calculation of speaking rate within a syllable.     

Balm in Gilead: Spiritual Dimensions in Counseling African American Women

The authors describe African American cultural and spiritual traditions that are the bedrock for therapeutic work with this population. Through the use of a clinical case, they link African American women's emotional issues with healing interventions borrowed from their rich heritage of religious and spiritual rituals and practices.     

Was Wittgenstein Frege's Heir

Dummett has claimed that Wittgenstein's views, as expressed in The Blue and Brown Books and Philosophical Investigations , build on the attack on psychologism initiated by Frege. Frege's rejection of psychologism led him to the view that the meanings of sentences are thoughts which objectively exist in a third realm. It was Wittgenstein, according to Dummett, who, inheriting Frege's insights, provided a genuinely anti-psychologistic account of understanding by insisting that we explain understanding a sentence in terms of the use that is made of it. I challenge this interpretation of the relationship between Wittgenstein and Frege. I argue that the analysis does not sufficiently distinguish anti-psychologism and anti-mentalism. In the light of this distinction we can see that Wittgenstein misrepresents Frege's views, and confuses concepts with ideas. By being more faithful to Frege's actual views concerning the objectivity of concepts we can give a robustly realist account of mathematical truth which does not involve any objectionable psychologism or mentalism.
email : Karen.Green@arts.monash.edu.au     

Information transmission with a multifinger tactual display

In this work, the tactual information transmission capabilities of a tactual display designed to provide stimulation along a continuum from kinesthetic movements to cutaneous vibrations are assessed. The display is capable of delivering arbitrary waveforms to three digits (thumb, index, and middle finger) within an amplitude range from absolute detection threshold to about 50 dB sensation level and a frequency range from dc to above 300 Hz. Stimulus sets were designed at each of three signal durations (125, 250, and 500 msec) by combining salient attributes, such as frequency (further divided into low, middle, and high regions), amplitude, direction of motion, and finger location. Estimated static information transfer (IT) was 6.5 bits at 500 mseC., 6.4 bits at 250 mseC., and 5.6 bits at 125 msec. Estimates of IT rate were derived from identification experiments in which the subject’s task was to identify the middle stimulus in a sequence of three stimuli randomly selected from a given stimulus set. On the basis of the extrapolations from these IT measurements to continuous streams, the IT rate was estimated to be about 12 bits/seC., which is roughly the same as that achieved by Tadoma users in tactual speech communication.     

Timing in Eyeblink Classical Conditioning and Timed-Interval Tapping

Abstract—The cerebellum is implicated in interval timing for diverse tasks including eyeblink classical conditioning (EBCC) and repetitive tapping. We examined performance on both tasks across identical intervals ranging from 325 to 550 ms. In five weekly sessions, 23 participants used a different interval each week, both as the target for tapping and as the delay interval in EBCC. Changes in variability as a function of the tapping or delay interval were assessed using regression analyses. The slope for repetitive tapping was comparable to two measures of temporal acuity in EBCC, onset and peak latency of the conditioned response. Each of 80 additional participants was assessed in one session at one of four tapping and delay intervals. Results were similar to those observed in the repeated measures group. These findings provide further evidence that EBCC and repetitive tapping utilize common mechanisms for representing temporal information.     

The encoding of rate and talker information during phonetic perception

The acoustic structure of the speech signal is extremely variable due to a variety of contextual factors, including talker characteristics and speaking rate. To account for the listener’s ability to adjust to this variability, speech researchers have posited the existence of talker and rate normalization processes. The current study examined how the perceptual system encoded information about talker and speaking rate during phonetic perception. Experiments 1–3 examined this question, using a speeded classification paradigm developed by Garner (1974). The results of these experiments indicated that decisions about phonemic identity were affected by both talker and rate information: irrelevant variation in either dimension interfered with phonemic classification. While rate classification was also affected by phoneme variation, talker classification was not. Experiment 4 examined the impact of talker and rate variation on the voicing boundary under different blocking conditions. The results indicated that talker characteristics influenced the voicing boundary when talker variation occurred within a block of trials only under certain conditions. Rate variation, however, influenced the voicing boundary regardless of whether or not there was rate variation within a block of trials. The findings from these experiments indicate that phoneme and rate information are encoded in an integral manner during speech perception, while talker characteristics are encoded separately.