Behavioral comparisons of hyperactive and normally active children in natural settings

Matched pairs of hyperactive and normally active children were observed in six natural classroom settings and a number of specific behaviors continuously recorded. Both groups of children showed differences in behavior as a function of settings (selected to vary in amount of external stimulation and structure), but only certain settings differentiated hyperactive from control children. Hyperactive children displayed significantly more noise-vocalization and more disruptive and off-task behavior in the most frequently observed (low stimulation) classroom settings (e.g., seat work). Type of off-task behavior (out-of-seat or visually off-task) depended upon amount of classroom structure (i.e., teacher- vs. self-directed). Results were discussed in terms of their implications for identification and treatment of hyperactive children through the modification of the antecedent conditions of stimulation and structure.     

Control of pigeons' matching-to-sample performance by differential sample response requirements

Pigeons were trained on a matching-to-sample task in which sample hue and required sample-specific observing behavior provided redundant, relevant cues for correct choices. On trials that involved red and yellow hues as comparison stimuli, a fixed-ratio 16 schedule (FR 16) was required to illuminate the comparisons when the sample was red, and a differential-reinforcement-of-low-rates 3-sec schedule (DRL 3-sec) was required when the sample was yellow. On trials involving blue and green hues as comparison stimuli, an FR 16 schedule was required when the sample was blue and a DRL 3-sec schedule was required when the sample was green. For some pigeons, a 0-sec delay intervened between sample offset and comparison onset, whereas other pigeons experienced a random mixture of 0-sec and 2-sec delay trials. Test trial performance at 0-sec delay indicated that sample-specific behavior controlled choice performance considerably more than sample hue did. Test performance was independent of whether original training involved all 0-sec delay trials or a mixture of 0-sec and 2-sec delays. Sample-specific observing response requirements appear to facilitate pigeons' matching-to-sample performance by strengthening associations between the observing response and correct choice.     

Most directed forgetting in pigeons can be attributed to the absence of reinforcement on forget trials during training or to other procedural artifacts.

In research on directed forgetting in pigeons using delayed matching procedures, remember cues, presented in the delay interval between sample and comparisons, have been followed by comparisons (i.e., a memory test), whereas forget cues have been followed by one of a number of different sample-independent events. The source of directed forgetting in delayed matching to sample in pigeons was examined in a 2 x 2 design by independently manipulating whether or not forget-cue trials in training ended with reinforcement and whether or not forget-cue trials in training included a simultaneous discrimination (involving stimuli other than those used in the matching task). Results were consistent with the hypothesis that reinforced responding following forget cues is sufficient to eliminate performance deficits on forget-cue probe trials. Only when reinforcement was omitted on forget-cue trials in training (whether a discrimination was required or not) was there a decrement in accuracy on forget-cue probe trials. When reinforcement is present, however, the pattern of responding established during and following a forget cue in training may also play a role in the directed forgetting effect. These findings support the view that much of the evidence for directed forgetting using matching procedures may result from motivational and behavioral artifacts rather than the loss of memory.     

Pigeons’ Performances of a Radial-Arm-Maze Analog Task: Effect of Spatial Distinctiveness

The Psychological Record - Pigeons were presented with a radial-arm-maze analog task involving five response keys in one of four spatial arrangements. Two of the arrangements involved...     

Transfer across delayed discriminations: evidence regarding the nature of prospective working memory.

Pigeons were trained successively either on 2 delayed simple discriminations or on a delayed simple discrimination followed by delayed matching-to-sample. During subsequent transfer tests, the initial stimuli from the 1st task were substituted for those in the 2nd. Performances transferred immediately if both sets of initial stimuli had been associated with the presence versus absence of food on their respective retention tests, and the direction of transfer (positive or negative) depended on whether the substitution involved stimuli with identical or different outcome associates. No transfer was found, however, when the initial stimuli were associated with different patterns of responding but food occurred at the end of every trial. These results are consistent with outcome expectancy mediation but are incompatible with response intention and retrospective coding accounts.     

Mediational use of internal representations of food and no-food events by pigeons

Two experiments were conducted with pigeons to determine whether internal representations of food and no-food events can act as mediators in the formation of new associations. Specifically we asked if the representation of an anticipated event can replace the event itself in an established conditional discrimination. In Phase 1 of both experiments pigeons were differentially autoshaped to peck hue stimuli, only one of which was followed by access to food. In Phase 2 they were trained on a symbolic 0-delay matching-to-sample (DMTS) task with food and no-food samples and line-orientation comparisons. In Phase 3 the birds were tested on a symbolic DMTS task in which the hue stimuli from Phase 1 were substituted for the Phase 2 food-event samples. For the Pos group, the hue followed by food in Phase 1 was substituted for the food sample and the hue associated with no-food was substituted for the no-food sample so that the resulting sample/comparison pairings were consistent with the food-event mediator. For the Neg group the pairings were reversed so that the sample/comparison pairings were inconsistent with the food-event mediators. In Experiment 1, when the no-food event was the absence of an event, acquisition of the transfer task was significantly more rapid in the Pos than in the Neg condition. In Experiment 2, when the no-food event was the presentation of an empty food hopper, the Pos group transferred at a significantly higher level than the Neg group. The two experiments provide evidence that in pigeons, representations involving event anticipations can be substituted for, and are thus similar to, the events themselves.     

Transfer of value from S+ to S- in simultaneous discriminations in humans

When animals learn a simultaneous discrimination, some of the value of the positive stimulus (S+) appears to transfer to the negative stimulus (S-). The present experiments demonstrate that such value transfer can also be found in humans. In Experiment 1 humans were trained on 2 simple simultaneous discriminations, the first between a highly positive stimulus, A (1,000 points); and a negative stimulus, B (0 points); and the second between a less positive stimulus, C (100 points); and a negative stimulus, D (0 points). On test trials, most participants preferred B over D. In Experiments 2 and 3 the value of the 2 original discriminations was equated in training (A[100]B[0] and C[100]D[0]). In Experiment 2 the values of the positive stimuli were then altered (A[1,000]C[0]); again, most participants preferred B over D. In Experiment 3, however, when the values of B and D were altered (B[1,000]D[0]), participants were indifferent to A and C. Thus, the mechanism that underlies value transfer in humans appears to be related to Pavlovian second-order conditioning. Similar mechanisms may be involved in assimilation processes in social contexts.     

Perceptual learning in pigeons: Decreased ability to Discriminate samples mapped onto the same comparison in many-to-one matching

Humans often treat two stimuli that are associated with a common response as similar in other contexts. They do so presumably because those stimuli become conceptually or perceptually more similar to each other (perceptual learning). An analogous phenomenon may occur in pigeons when they are trained with a matching-to-sample procedure in which more than one sample is mapped onto the same comparison. In the present research, pigeons were trained to select one comparison following either of two samples (S₁ or S₂) and to select the other comparison following either of two different samples (S₃ or S₄). When the samples were then presented as positive and negative stimuli in a simple successive discrimination, samples that had been associated with the same comparison during original training (e.g., S₁ vs. S₂) were more difficult to discriminate than were samples that had been associated with different comparisons (e.g., S₁ vs. S₃). Thus, it appears that perceptual learning occurs in pigeons as well.     

Same/different concept learning in the pigeon: the effect of negative instances and prior adaptation to transfer stimuli

Pigeons were trained on a matching-to-sample or oddity-from-sample task with shapes (circle and plus). Half of each group was exposed to “negative instance” trials i.e., for matching birds, neither comparison key matched the sample, and for oddity birds both comparison keys matched the sample. When all birds were transferred to a new task involving colors (red and green), nonshifted birds (transferred from matching to matching, or oddity to oddity) performed significantly better than shifted birds (transferred from matching to oddity, or oddity to matching), but only if they had experienced negative instances of the training concept. When all birds were exposed to negative instances of the transfer task and then transferred to a new color task (yellow and blue), dramatic transfer effects were observed. The effect of pre-exposure to the yellow and blue colors, in order to reduce transfer-stimulus novelty, had a minor effect on transfer.     

Absolute pitch: frequency-range discriminations in pigeons (Columba livia): comparisons with zebra finches (Taeniopygia guttata) and humans (Homo sapiens)

Absolute pitch (AP) is the ability to classify individual pitches without an external referent. The authors compared results from pigeons (Columba livia, a nonsongbird species) with results (R. Weisman, M. Njegovan, C. Sturdy, L. Phillmore, J. Coyle, & D. Mewhort, 1998) from zebra finches (Taeniopygia guttata, a songbird species) and humans (Homo sapiens) in AP tests that required classification of contiguous tones into 3 or 8 frequency ranges on the basis of correlations between the tones in each frequency range and reward. Pigeons' 3-range discriminations were similar in accuracy to those of zebra finches and humans. In the more challenging 8-range task, pigeons, like zebra finches, discriminated shifts from reward to nonreward from range to range across all 8 ranges, whereas humans discriminated only the 1st and last ranges. Taken together with previous research, the present experiments suggest that birds may have more accurate AP than mammals.