Stimulating basic reading processes using auditory discrimination in depth

Recent research indicates that a major cause of reading (decoding) disabilities lies in an inability to manipulate speech at its phonemic (phonological) level. The Auditory Discrimination in Depth Program (ADD Program), stimulates basic phonological awareness and has been used extensively at The Reading Foundation in Calgary, Alberta. Here we present pre- and post-test data from 281 clients (ranging from school-age through adulthood) seen over a two-year period; post-test data was collected after 80 hours of ADD instruction. To assess whether significant gains had been achieved, an analysis of covariance was performed, covarying for age and initial vocabulary scores. After 80 hours of intensive instruction, highly significant gains (p<.001) were evident on measures of phonological awareness, sound/symbol connections, word identification, spelling, and decoding in context. In addition to the treatment effect, age and vocabulary had some influence on some of the variables. The data was also analyzed to determine whether the results went beyond a “group effect” only. A total of 229 cases were tabulated for gains or losses on the word attack subtest and on the reading and spelling subtests of the WRAT-R. Results indicate that the remediation was effective for all subjects, though gains on spelling tended to be less than on the two reading scores.     

Processing of complex auditory stimuli (tunes) by rats and monkeys (Cebus apella)

The degree to which rats and monkeys base their discriminations of complex auditory stimuli (“tunes”) on frequency contours rather than on local features was investigated. In Experiment 1, groups of rats and monkeys trained with tunes as S+ and S? acquired a simple operant discrimination no faster than groups that received the same notes of each tune but in a new random order on each trial; neither did the groups differ on two transfer tests devised to detect learning of frequency contour in the tune-trained animals. Acquisition in the tune-trained and random-notes groups seemed to be based on the overall frequency difference between S+ and S?, which was about 1.5 octaves. In Experiment 2, S+ and S? were similar to each other with regard to overall frequency and individual notes, the most salient differentiating characteristic of the tunes being their tonal pattern. The tune-trained groups were clearly superior to the random-notes animals in acquisition, and an initial transfer test suggested that the former might have learned the discrimination on the basis of frequency contour. However, the detailed transfer tests of Experiment 3 strongly suggested that the tune-trained rats and monkeys based their discriminations primarily on local cues rather than on frequency contour. Based on the results of Experiment 4, the data of an earlier study that suggested frequency contour learning in monkeys and rats were reinterpreted in terms of control by local cues.     

Reinstatement of postresponse stimuli prior to reward in delayed-reward discrimination learning by pigeons

Delayed-reward learning in pigeons was examined using a simultaneous red-green visual discrimination task in which the conditions during the delay interval were varied between groups. The nondifferential group received training in which the stimulus present during the 1-min delay was the same following a peck on the correct and incorrect colors. The other three groups received 1-min delay training in which different stimuli occurred in the delay interval following correct and incorrect choices. The differential group received continuous, differential stimuli during the delay. The reinstatement group received the differential stimuli in the 10 sec immediately following the choice and during the last 10 sec of the delay. The reversedcue group was treated in the same way, except that the 10-sec delay stimulus immediately following an incorrect response was also presented for 10 sec prior to reward on correct choices, and the stimulus following a correct response also occurred 10 sec before nonreward on incorrect choices. Nondifferential birds failed to learn the discrimination, while differential and reinstatement birds learned it readily. The reversed-cue birds learned to choose the incorrect stimulus. Differential and reinstatement birds showed no decrement in performance when the delay was increased to 2 min. These findings suggest that similarity of prereward and postresponse delay stimuli controls choice responding in long-delay learning, a finding compatible with both memorial and conditioned reinforcement interpretations.     

A bowed serial-position function in habituation of sequential stimuli

The effect of serial position was examined in a study of habituation of the vasoconstrictive orienting response in rabbits. In a procedure analogous to a recognition memory test, subjects received multiple exposures to an invariant list of stimuli before their response was assessed to an isolated item that had consistently occupied either the first, middle, or last position in the list. A reliably bowed serial-position function was obtained, with the least habituation (poorest retention) occurring for the item that had occupied the middle position in the list. The finding of both a primacy and a recency effect parallels the most general finding in studies of human memory and encourages a compatible account of habituation in infrahuman subjects. The result was discussed in terms of the opportunities for differential rehearsal of list items and contextual cues at different positions in the list.     

Infants' tactual discrimination of novel and familiar tactual stimuli

40 10-month-old infants were given 2 min to explore tactually an object in a totally darkened room. Subsequently, during a 2-min test trial in the dark, half of the infants were given the same object and half were given a novel shape. Infants presented with the novel shape evidenced significantly longer durations of manipulation than infants presented with familiar forms. Infants are thus capable of tactually discriminating novel and familiar shapes in the absence of vision and demonstrate a preference for novelty within the tactual modality.     

Social influence on avoidance of dangerous stimuli by rats

Three experiments were conducted to determine whether a naive observer rat would avoid contact with a shock prod after watching a demonstrator rat contact, be shocked by, and defensively bury the prod. We found that observer rats took longer to contact prods that had delivered a shock to and been buried by a demonstrator rat than to contact prods that had not delivered shock and had not been buried. However, observer rats contacted prods buried by an unseen demonstrator rat or by an unseen experimenter with the same latencies as those for prods they had seen deliver shock to and be buried by a demonstrator rat. In large enclosures, subjects took 1–2 h longer to contact buried prods than to contact unburied prods. We conclude that alteration of the physical environment by individuals receiving noxious stimulation can significantly reduce the probability that conspecifics will contact the noxious stimulus. Observational learning per se, however, need not be involved.     

Short-term memory for visual and auditory stimuli in pigeons

Separate groups of pigeons were trained to perform symbolic delayed matching to sample with auditory and visual sample stimuli. For animals in the auditory group, ambient tones that varied in frequency served as sample stimuli; for animals in the visual group, ambient red and green lights served as sample stimuli. In both cases, the sample stimuli were mapped onto the yellow and blue comparison stimuli presented on left and right pecking keys. In Experiments 1 and 2, it was found that visual and auditory delayed matching were affected in the same ways by several temporal variables: delay, length of exposure to the sample stimulus, and intertrial interval. In Experiments 3, 4A, and 4B, a houselight presented during the delay interval strongly interfered with retention in both visual and auditory groups, but white noise presented during the delay had little effect in either group. These results seem to be more in line with a prospective memory model, in which visual and auditory sample stimuli are coded into the same instructional memories, than with a model based on concepts of retrospective memory and modality specificity.     

Discrimination of the number of sequential events by rats

Ten rats were trained to press a right lever following two successive sounds and to press a left lever following four successive sounds. Three sound sequences were used in initial discrimination training, such that reliable classification could not be based on the duration of each sound, the interval between sounds, or the total duration of the sound sequence. Classification of seven novel sound sequences suggested that the animals were either using number or the sum of sound durations in a sequence as the relevant cue. When this total sound duration was put in conflict with number, rats classified by number. The conclusion was that rats can discriminate number, even when temporal cues are controlled.     

The perception of time relations in auditory tempo discrimination

European starlings (Sturnuis vulgaris) were trained to discriminate between pulses of sound presented at rates (tempos), for different birds, of 4/sec and 8/sec or 8/sec and 16/sec in a two-alternative choice task. Once the discrimination was learned, psychometric functions and bisection points were determined for tempos between the standards. Then the starlings were transferred to a new discrimination, which either maintained or changed the relationship between response keys and tempo (relational or nonrelational transfer). The results showed that the starlings generated psychometric functions for tempo with properties much like those found for discrimination of single time intervals. Also, the starlings transferred the tempo discrimination faster under the relational than the nonrelational condition. In general, starlings-like human and other nonhuman animals-perceive temporal structures as invariant over proportional changes in the duration of structural elements.     

Stimulus generalization in monkeys following discrimination training with gray stimuli

Eight rhesus monkeys were trained on a successive discrimination problem with light gray and dark gray stimuli. Following training, generalization tests were given with variable stimuli ranging from white to black. Responses and response latencies were recorded. Responses were faster to the training stimulus values than to middle grays or to the extreme values on the lightness continuum. The theoretical implications of this as compared to other possible findings are developed.     

Sensitivity to auditory and visual stimuli during early reading development

An investigation was conducted into the visual and auditory temporal processing profiles of two groups of 4‐ to 6‐year‐old children: pre‐alphabetic children, who showed no alphabetic ability (failing to read any non‐words in a test), and those who demonstrated some alphabetic ability. This alphabetic group showed higher scores in reading and spelling attainment than the pre‐alphabetic group. They were also faster than the pre‐alphabetic group in reacting to the onset and offset of auditory and visual stimuli. However, when age was used as a covariate, only reaction times (RTs) to the offsets of visual stimuli were found to be faster in the alphabetic than the pre‐alphabetic group. This suggests that responses to the offset of visual stimuli are becoming more rapid during the same developmental period when alphabetic ability is beginning to be acquired. Within the alphabetic group, after accounting for age, visual and auditory onset RTs were strongly correlated, whereas within the pre‐alphabetic group there were high correlations between visual and auditory offset RTs. It is therefore suggested that a strong association between RTs to visual and auditory onsets may be beneficial during early alphabetic acquisition, when phoneme–grapheme associations are established. Multiple regression analyses showed visual offset RT as the only variable to account for a significant amount of variance in spelling attainment after age was taken into account, which may relate to Frith's (1985) contention that spelling is important in driving early alphabetic ability.     

Response cost and time-place discrimination by rats in maze tasks

Time-place discrimination has been shown reliably in several avian and insect species, but only occasionally in rats and fish. In the present experiments, we explored the effects of response cost on time-place discrimination by rats. In the first experiment, we increased the cost of making a choice and the cost of recovering from a wrong choice in two types of maze, a radial arm and a vertical maze. In the radial arm maze, we found only general place preference, whereas in the vertical maze, we obtained evidence of time-place discrimination. In the second experiment, we found that the proportion of rats showing time-place discrimination increased with the height and, therefore, the response cost of the vertical maze. These results suggest that rats do not automatically store and/or retrieve the time and place of reward events but that response cost is an important trigger for time-place discrimination.     

Tests of the conditioned reinforcement value of sequential stimuli in pigeons

Egger and Miller (1962) hypothesized that the conditioned reinforcing value of stimuli depends on their information value. Egger and Miller and others have tested this hypothesis by comparing the conditioned reinforcing value of S1 and S2 following S1-S2-reward training. However, none of these experiments have controlled for differential generalization of conditioned reinforcement value from training to comparison tests. That is, the S1 cue pattern during the conditioned reinforcement tests has been very similar to the S1 cue pattern of training, while the training and test S2 cue patterns have been quite dissimilar. In Experiment 1, pigeons in a procedure unconfounded by differential generalization produced S2 reliably more frequently than S1, and pigeons in a confounded procedure produced S1 somewhat more frequently than S2. A significant groups × stimuli interaction was attributed to differential stimulus generalization from training to test for S1 and S2 in the confounded condition. In Experiment 2, pigeons in an unconfounded procedure again produced S2 reliably more frequently under a different testing procedure. The results are interpreted as demonstrating that, following S1-S2-food training trials, S2 is the more effective conditioned reinforcer in unconfounded conditions. A reconceptualization of the information hypothesis is shown to be consistent with these results.     

Factors affecting conditional discrimination learning by pigeons: II. Physical and temporal characteristics of stimuli

Four experiments were performed to determine the stimulus characteristics that favor the development of conditional stimulus control in the single reversal paradigm with pigeon subjects. In Experiment 1, pigeons were trained on a successive discrimination between tone frequencies ranging from 350 to 3500 Hz in a particular houselight context condition (houselight-on or -off). The subjects then were trained on the reversal of the tone discrimination in the alternative context. Subsequent tone-frequency generalization testing in the two contexts indicated that they had failed to gain conditional control over the pigeons’ discriminative performance. Such control was obtained in Experiment 2, in which the two problems were alternated daily for 32 sessions of training. The gradients then peaked at the appropriate S+ value in each context. In Experiment 3, the key colors (blue vs. red) served as contexts while pigeons learned a successive discrimination in which the discriminative cues were houselight-on versus houselight-off conditions. This was followed by a reversal of the discrimination in the alternative key-color context condition. The key colors were effective conditional cues in this situation. In a previous experiment (Thomas, McKelvie, & Mah, 1985), key color had been ineffective as a conditional cue when the discriminative cues were lines superimposed on the colored background. In Experiment 4, key color was effective when the color and lines were presented on a single key as in the earlier experiment, but were sequenced such that the onset of the key color preceded and then overlapped the presentation of the lines. We concluded that conditional discriminations are easiest for pigeons when visual cues are used, but the conditional and discriminative cues must be presented in such a way that they do not combine to form a psychological compound.     

Stimulus blocking during compound discrimination training with pentobarbital and visual stimuli

Learning & Behavior - To investigate blocking by drug-induced stimuli and visual stimuli, three groups of rats were trained to escape shock in a T-maze by choosing the left or right arm. During...