Pattern identification of pure tones and frequency glides by untrained listeners

Six subjects identified the order of four-event sequences. Contiguous pure tones (713, 1,031, 1,209, and 1,514 Hz in permuted orders) were presented by earphones at 40 dB SL, with individual events Itones) from 20, to 40, 60, and 300 msec in duration. Again, silent intervals of 20 or 60 msec were inserted among tones of 20 or 40 msec duration. Finally, the pure tones of 713 and 1,209 Hz were combined, in any four-event sequence, with two glissandi chosen from 466 to 714 Hz, from 714 to 1,208 Hz, and their mirror reversals. The temporal and frequency continuity both of tonal and of glissando-plus-tonal sequences affected the identification of sequential order. Degraded performance in the glissando-plus-tonal condition was attributed partially to a subjective experience of pitch blurring. The inclusion of silent intervals in the sequences of the shorter pure-tone durations improved identification performance to that of contiguous sequences of equal overall duration, i.e., adding silent processing time was as efficacious as increasing by the same amount the duration of the individual frequency event.     

Inadequacy of recall as a basis for frequency knowledge.

Subjects studied a word list comprising varying numbers of words from distinct semantic categories. The category names (trees, colors, etc.) were then re-presented, and for each name subjects either recalled as many exemplars as they could or estimated how many had been included in the list (Experiments 1 and 2). Recall was not sufficiently informative about actual category sizes to account for performance in the frequency estimation task. Moreover, it remained insufficiently informative when efforts were made to induce a recall-estimate strategy by requiring overt recall prior to estimation (Experiments 3-5), by using very small categories (Experiment 4), and by not showing the category name at study (Experiment 5), even though it did allow a partial account of estimation when the category exemplars were individually cued (Experiment 6). It is concluded that the role of recall in frequency estimation is much exaggerated.     

Frequency discrimination of complex periodic tones

When the components of a two-tone periodic complex differ slightly in amplitude and frequency, the pitch is shifted toward the more intense tone. This well-known phenomenon has been explained by differences in the instantaneous frequency functions of the complex tones. In this experiment, three listeners were asked to discriminate between complementary pairs of two-component complex tones. The results indicate that discriminability may depend upon differences in the envelope-weighted instantaneous frequency functions of the two-tone complexes.     

Body sway during long-term standing and as affected by pure tones

Sixty students, male and female, were used as Ss to test the effect of a 1, 000-Hz, 5-sec tone at 0, 70, and 90 dB, on standing sway. In general, antero-posterior sway was greater than lateral, and males swayed more than females in both directions. In addition, males increased their sway in time, whereas females did not. Only lateral sway in the 5-sec interval after the presentation of the tone increased, and only after 10, 15, and 20 min of standing, with a maximum at 15 min. Amplitude of lateral sway appeared independent of bodily characteristics, and is suggested as being more useful for comparing Ss than is antero-posterior sway.     

Streaming vs. fusion of sinusoidal components of complex tones

The present experiments looked at the effect of a number of variables on the tendency of an element of a complex tone to either fuse with the other elements of the tone or be “pulled out” into a “horizontal,” temporal stream. It was found that such factors as the intensity relationship of the elements of the complex tone, the frequency of the tone being pulled out, and various factors producing temporal asynchronies between elements of the complex, all affect the tendency for either fusion or streaming to occur.     

Programmed presentation of pure tones of different frequencies using a single oscillator

A simple and inexpensive method is described for the programmed presentation of pure tones of different frequencies using a single oscillator.     

Preference for tones as a function of frequency (hertz) and intensity (decibels)

An extension of the Wundt hypothesis concerning stimulus intensity and hedonic tone leads to the prediction that Ss prefer tones of intermediate frequency (hertz) and of intermediate intensity (decibels). In Experiment 1, tones varying from 60 to 5000 Hz were presented in a paired comparison procedure, and, as predicted, Ss′ preference was an inverted-U-shaped function of frequency, with the most preferred tones in the range of 400–750 Hz. In Experiment 2, tones varying in intensity from 40 to 90 dB were also presented in a paired comparison procedure, and again the predicted inverted-U-shaped preference function was found, with 50 dB as the preferred intensity. Related research and some unexpected findings are discussed.     

Infants' discrimination of number vs. continuous extent

Seven studies explored the empirical basis for claims that infants represent cardinal values of small sets of objects. Many studies investigating numerical ability did not properly control for continuous stimulus properties such as surface area, volume, contour length, or dimensions that correlate with these properties. Experiment 1 extended the standard habituation/dishabituation paradigm to a 1 vs 2 comparison with three-dimensional objects and confirmed that when number and total front surface area are confounded, infants discriminate the arrays. Experiment 2 revealed that infants dishabituated to a change in front surface area but not to a change in number when the two variables were pitted against each other. Experiments 3 through 5 revealed no sensitivity to number when front surface area was controlled, and Experiments 6 and 7 extended this pattern of findings to the Wynn (1992) transformation task. Infants' lack of a response to number, combined with their demonstrated sensitivity to one or more dimensions of continuous extent, supports the hypothesis that the representations subserving object-based attention, rather than those subserving enumeration, underlie performance in the above tasks.     

Location serves as a conditional cue when harp seals (Pagophilus groenlandicus) solve object discrimination reversal problems.

We examined the capacity of harp seals (Pagophilus groenlandicus) to use spatial context (i.e., their tank) as a conditional cue to solve a two-choice visual discrimination reversal task. Seals were trained to touch one of two 3D objects. Two of four seals experienced a context shift that coincided with each of five reversals in the reward value of the two stimuli (i.e., a reversal of S+ and S-); these seals solved the six discriminations in significantly fewer trials than did seals that did not experience a context shift with the contingency reversal. Thus, harp seals use contextual cues when encoding information. The findings are discussed in terms of harp seals' adaptations to the pack-ice environment, the constraints of the learning tasks, and the nature of the subjects that were raised in captivity.     

Sequence effects in the categorization of tones varying in frequency

In contrast to exemplar and decision-bound categorization models, the memory and contrast models described here do not assume that long-term representations of stimulus magnitudes are available. Instead, stimuli are assumed to be categorized using only their differences from a few recent stimuli. To test this alternative, the authors examined sequential effects in a binary categorization of 10 tones varying in frequency. Stimuli up to 2 trials back in the sequence had a significant effect on the response to the current stimulus. The effects of previous stimuli interacted with one another. A memory and contrast model, according to which only ordinal information about the differences between the current stimulus and recent preceding stimuli is used, best accounted for these data.     

Neural control of fundamental frequency rise and fall in Mandarin tones

The neural mechanisms used in tone rises and falls in Mandarin were investigated. Nine participants were scanned while they named one-character pictures that required rising or falling tone responses in Mandarin: the left insula and right putamen showed stronger activation between rising and falling tones; the left brainstem showed weaker activation between rising and falling tones. Connectivity analysis showed that the significant projection from the laryngeal motor cortex to the brainstem which was present in rising tones was absent in falling tones. Additionally, there was a significant difference between the connection from the insula to the laryngeal motor cortex which was negative in rising tones but positive in falling tones. These results suggest that the significant projection from the laryngeal motor cortex to the brainstem used in rising tones was not active in falling tones. The connection from the left insula to the laryngeal motor cortex that differs between rising and falling tones may control whether the rise mechanism is active or not.     

Frequency ratios and the discrimination of pure tone sequences

We examined the effect of frequency ratios on the discrimination of patterns of alternating pure tones (ABABA). Listeners heard a repeating pattern presented in transposition (same frequency ratios between successive tones, different absolute frequencies) and were required to indicate when the pattern changed (different frequency ratios and absolute frequencies). Changes from patterns with simple frequency ratios to those with more complex ratios were more readily detected than were changes from complex ratios to simpler ratios.     

Nicotine vs. ethanol discrimination: Extinction and spontaneous recovery of responding

Studies regarding extinction and spontaneous recovery of the discriminative stimulus effects of drugs are limited. Eight rats were initially trained to discriminate nicotine (0.4 mg/kg) vs. ethanol (800 mg/kg). For four rats, itraperitaneal (IP) administrations of nicotine fifteen minutes prior to fifteen-minute training sessions served as a discriminative stimulus (S^D) for predicting food-reinforced lever pressing (VI-1 min). On other sessions ethanol functioned in predicting nonreinforcement (S^Δ). The stimulus roles of the drugs were counterbalanced for the remaining four rats. S^Δ and S^D sessions alternated quasi-randomly with two daily sessions at 1000 and 1400 hours. Discriminative control was not disrupted following ten extinction sessions under a non-drug/saline condition, but was disrupted following extinction sessions under the original training drugs. Instances of spontaneous recovery (SR) occurred throughout extinction under the drug condtions. There was no evidence for SR two weeks following extinction, but partial recovery four weeks following the final extinction phase. Contextual status (context renewal) had neither a restorative or disruptive impact on extiguished or discriminated responding, respectively. Theser results support and extend the limited number of other studies by demonstrating extinction and spontaneous recovery of responding discriminated bytwo distinct drugs. Some theoretical interpretations regarding history effects and training in the context of drug discrimination are entertained.