Numerosity differences and effects of stimulus density on pigeons’ discrimination performance

Two experiments are described in which pigeons were trained in a simultaneous conditioning procedure to discriminate small arrays of dots that differed in numerosity. The birds successfully learned to choose the array of each pair that contained fewer dots when these choices were reinforced and choices of the array with more dots led to timeout. For the majority of numerosity values tested, discrimination performance for a fixed S+ value was better when the numerical difference between S+ and S-values was larger rather than smaller. This effect was seen in the first experiment when the numerical difference value was shifted between training trials and novel test trials. In the second experiment, too, performance level depended on the size of the numerosity difference when the birds were concurrently trained with two difference values that varied across trials within sessions. However, discrimination accuracy was influenced secondarily by variations in the density, or interdot spacing, of the stimulus arrays. In order to explain the latter finding, it is suggested that a tendency to “scan” a lowdensity array incompletely might alter the probability of accepting it as the smaller numerosity (S+) stimulus. This would increase error rates with S? arrays in which the dots are more widely spaced.     

Nondifferential training of pigeons retards acquisition of subsequent discriminations involving other stimuli

In Experiment 1, two groups of pigeons (n = 8) were given nondifferential (ND) training with a green keylight and a white vertical line on a dark surround nonsystematically alternated. Two groups (n = 8) received single stimulus (SS) training with the green light only. In Experiment 2, two groups of pigeons (n = 8) were given ND training with vertical and horizontal lines, while two other groups (n = 8) received SS training with only the vertical line. In both experiments, all groups were transferred to a green S+ (VI reinforced) and a red S? (extinguished) transfer problem. In each experiment, one ND and one SS group was tested in the same context as initial training (houselight off) and one ND and one SS group was tested in a changed context (houselight on). In both experiments and in both contexts, the ND groups performed less well on the transfer problem than did the SS groups. There was no evidence of greater control by the context in ND than in SS groups, which suggests that the observed difference in acquisition of the transfer task is not attributable to a purported difference in control by the context under the two conditions. The overall results favor the position that nondifferential training reduces attention to stimuli involved in the original training procedure and that this reduced attention transfers to stimuli subsequently experienced.     

C_m·S_n的邻点可区别边染色

V(Cm·Sn)={ui|i=1,2,L,m}∪{vij|i=1,2,L,m;j=1,2,L,n}, E(Cm?Sn)={v11v21,v21v31,Lv(m?1)1vm1,vm1v11}∪{uivij|i=1,2,L,m;j=1,2,L,n}.本文给出了的邻点可区别的边色数。     

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.     

Interference in pigeons’ long-term memory viewed as a retrieval problem

In Experiment 1, three (experimental) groups of pigeons (n=8) acquired a successive wavelength discrimination in Phase 1 and a reversal in Phase 2; then, after a 24-h delay, they received a wavelength generalization test in extinction (Phase 3). For one group (“Context Same”), the same context was present throughout; for both others, a different context was used for Phase 1 and Phase 2. One group received the generalization test in the presence of Context 1, the other in Context 2. The Context Same and Context 2 experimental groups showed “recency,” with all gradients peaking at the reversal S+ value. The Context 1 group yielded several different response patterns but never showed recency, thus revealing context-generated proactive interference. In Experiment 2, eight subjects learned the original discrimination and its reversal in different contexts, and each bird was tested alternately (within a session) in both contexts. Under this condition, the test contexts were effective retrieval cues. In every case, the gradients obtained in each context peaked sharply at the appropriate S+ value. These experiments indicate that conflicting memories may be stored along with their associated contexts such that they can be retrieved by an appropriate manipulation of contextual cues at the time of retention testing.     

海滨车前和毛车前的核型研究

文章对我国2种车前属Plantago植物的核型进行了分析.2个种的染色体数目均为2n=2x=12.它们的核型是:海滨车前P.camtschatica Link,Enum.2n=2x=12=8m+4sm;毛车前P.jehohlensis Koidz.2n=2x=12=6m+4sm+2st.它们的核型均属“2A”型.染色体相对长度组成P.camtschatica Link,enam.2n=2L+4M_2+4M_2+2S_1,P.jehoensis koidz.2n=6M_2+6M_1.由12条染色体组成.     

人工感染E.tenella鸡嗜酸性细胞的动态变化

8 0羽 2 1日龄罗曼蛋公鸡随机分成试验与对照两组 ,研究雏鸡在 2 1日龄人工感染E .tenella后第 1、2、3、4、5、6、7、8天鸡嗜酸性细胞的动态变化。结果表明 :感染E .tenella之后 ,试验组比对照组嗜酸性细胞明显增多 ,每日组间差异均极显著 (P <0 .0 1 ) ;在感染后第 1～6天 ,试验组日间差异不显著 (P >0 .0 5 ) ,在感染后第 6～ 7天 ,试验组日间差异极显著 (P <0 .0 1 ) ,而在感染后第 7～ 8天日间差异显著 (P <0 .0 5 )。     

Effect of N-R transitions during partial reinforcement pretraining on subsequent resistance to discrimination

Three groups of 12 rats received 25 pretraining trials to each future discriminandum employed in a subsequent differential brightness conditioning problem. Groups NR and RN received partial reinforcement (PRF) pretraining either with or without, respectively, transitions from nonrewarded to rewarded trials (N-R transitions). Group CRF received consistent reinforcement during pretraining. A fourth group (n=12), Group NP, received no pretraining. During discrimination learning, one-half of the rats in each group received all their daily S+ trials preceding their daily S? trials (+? sequence); the remainder of the rats received an intermixed sequence of trials to S+ and S? (+?+ sequence). Discrimination learning was faster under the +? sequence than under the +?+ condition, and discrimination learning was retarded in Group NR relative to the other three groups, which did not differ from one another, under both the +? and +?+ discrimination sequence conditions. The results are discussed with Reference to previous experiments demonstrating N-R transition effects on discrimination learning, a theoretical extension of sequential theory to discrimination learning, and the effects of nondifferential reinforcement prior to discrimination learning on learned irrelevance.     

A step function in pigeons’ temporal generalization in the peak shift task

Pigeons were reinforced for pecking a key following one signal duration (S+) but not following another signal duration (S?). The S+ and S? were 2.52 and 5.67 sec, respectively, counterbalanced across birds. Subsequent generalization tests with a range of signal durations revealed a step function, with high response rates for all durations on the S+ side of the distribution, low response rates for all durations on the S? side, and an intermediate rate for the intermediate duration. A comparison group of pigeons trained with only the S+ duration showed a flat generalization function. For the discrimination-trained birds, the delay between signal termination and opportunity to respond was subsequently varied during generalization testing. A step function again appeared, and no evidence of subjective shortening over the delay was found. The overall pattern of results suggests that the birds categorized the temporal signal into two classes and retained a categorical code over the delay.     

鸟类疟原虫模式宿主的探讨

本文描述了在鸟类疟原虫的研究中,发现一种可用作疟原虫模式宿主的鸟种:红耳鹎(Pycnonotus jocosus)。     

A new science and engineering career interest survey for middle school students

This study describes the development and validation of a science and engineering (S/E) career interest survey (CIS). This 56 question survey was developed to measure the overall S/E career interests of 7th through 9th grade students. In the CIS, a S/E career is characterized as one which requires the completion of at least a four-year college program with a major in science, science education, or engineering. The CIS is divided into four major parts. In Part I (30 questions), students are expected to select from occupational activities, while in Part II (20 questions) they are to select from various occupations. Part III (5 questions) and Part IV together make up the CIS internal verification scale. The CIS test-retest reliability coefficients for one week and eight months were calculated as 0.96 (n = 57, grades 7–9) and 0.78 (n = 1937, grade 8), respectively. The KR-21 estimate for the CIS was calculated as 0.92. Criterion-related validity coefficients were calculated in two ways: (a) CIS scores were correlated with the Kuder GIS science subscale (r = 0.75, n = 45, grades 7–9), and (b) CIS scores were correlated with a CIS internal verification scale (r = 0.59, n = 127, grades 7–9). Evidence to support the construct validity of the CIS was collected by two methods: (a) for 7–9 grade students (n = 45), the CIS score was found to correlate 0.75 with the scientific subscale and ?0.42 with the artistic sub-scale, of the Kuder GIS. (b) the second method compared the scores of known groups. Test results for students in grades 7-9 (n = 127; n = 1937) showed a statistically significant difference between the scores of boys and girls on S/E career interest. The readability of the CIS was seventh grade level.     

南洞庭湖湿地鸟类群落结构及多样性分析

2005年5月~2007年4月采用固定样带法和样点法对南洞庭湖自然保护区的鸟类群落进行了调查研究,共纪录到鸟类164种,隶属16目42科96属,其中冬候鸟84种、夏候鸟30种、留鸟38种,旅鸟12种,分别占51.22%、18.30%、23.17%、7.32%;古北界种类87种(占52.5%,另有新北界种类1种),东洋界种类43种(占26.9%),广布型种类33种(占20%);国家Ⅰ级保护种类6种,国家Ⅱ级保护种类29种。南洞庭湖湿地鸟类群落多样性指数(Shannon-Wiener)为3.991 0,均匀性指数(Pielou)为0.542 4。通过对该区的鸟类群落结构及多样性进行分析研究,进一步摸清了南洞庭湖湿地鸟类生存现状、类型、分布,从而研究洞庭湖的鸟类资源及生态环境提供科学依据。     

Numerical discrimination by rats using sequential auditory stimuli

Three rats were trained under a discrimination procedure in which responding was reinforced only following the repeated presentation of three bursts of white noise (S+). S? consisted of presentations of either two or four bursts of noise. All animals responded significantly more in the presence of S+ and, in two cases, showed lower response rates to both “2” and “4” stimuli. Responding by the third animal revealed differentiation between S+ and the stimulus “2,” but no reliable suppression to stimulus “4.” The present instances of discriminative control by the stimulus “3” replicate Fernandes and Church’s (1982) demonstration of control by sequential auditory stimuli in the rat. Moreover, because the present procedure involves adjacent S? values both greater as well as less than S+, these results extend our knowledge of the rat’s abilities with sequential auditory stimuli: Rats are capable of making intermediate numerical discriminations based upon something other than a simple many-versus-few dichotomy.     

沱江内江段冬季鸟类群落多样性研究

2007年11月至2008年3月采用路线调查法对沱江内江段地区冬季鸟类群落进行了调查,共记录到鸟类8目27科56种;其中留鸟27种（占48．2％）,冬候鸟17种（占30．4％）,夏候鸟4种（占7．1％）,旅鸟8种（占14.3％）;区系分析显示,共有东洋界鸟类11种（占19．6％）,古北界鸟类26种（占46．4％）,广布种鸟类19种（占34％）;多样性分析得出沱江内江段鸟类群落多样性指数H在4条调查样线区域分别为：1．26,1．29,1．29,1．22,冬季鸟类群落多样性指数2．53;均匀性指数分别为0．79,0．80,0．80,0．79．优势种为白鹊鸽（P=0．15）,白颊噪鹛（P=0．10813）．     

Pigeons’ short-term memories for surprising vs. expected reinforcement and nonreinforcement

Pigeons performed a delayed matching-to-sample task in which they matched red and green disks as comparison stimuli to samples of food and no food. The birds were also taught a discrimination between two lines: vertical (S+) followed by food and horizontal (S?) followed by no food. The two kinds of trials were then chained in infrequent probes such that (a) S+ and S? preceded samples of food and no food, (b) a longer than usual delay occurred, and then, (c) the comparison stimuli were presented. Therefore, in probes when S+ preceded food and S? preceded no food, the samples were “expected. ” But in probes when S+ signaled no food and S? signaled food, the samples were “surprising. ” Matching to surprising samples was more accurate than matching to expected samples. This result completes a pattern of findings implying that surprising reinforcers enhance learning and also persist (are longer rehearsed) in short-term memory.     

Some effects of early social stimulation on the emotional reactivity of ducklings

Newly hatched Khaki Campbell ducklings were housed with a conspecific for 24 h beginning at either 1 or 5 days of age. A third group of ducklings received no social stimulation. When tested on Day 7, ducklings afforded early social stimulation exhibited less distress calling and crouching in a novel open field than ducklings exposed to late or no social stimulation. A second experiment asked whether the above result was due to early social stimulation per se or to the separation which occurred at its termination. Newly hatched ducklings were housed with a conspecific beginning on Day 1. One-half of the birds were separated from their companions on Day 2; the rest were separated on Day 6. On Day 7, the ducklings that were separated early exhibited less crouching and distress calling in a novel open field than the birds that were separated late. This finding implies that the withdrawal of social stimulation, rather than social stimulation perse, was responsible for the reduced emotional behavior observed in Experiment I. It is concluded that early withdrawal of social stimulation generated a strong aversive reaction and that it was the strength and timing of this reaction that mediated the emotionality moderating effects found here. Under these circumstances, the primary function of early social stimulation was to establish a condition whereby the aversive reaction generated by separation would occur early.     

Signaling the omission of a response-contingent outcome reduces discriminative control

The effect of training a positive discriminative stimulus (S+ ) as a signal for the nonreinforcement of an instrumental response (S?) on the ability of that stimulus to evoke its original instrumental response was examined in three experiments using rats. In all three experiments, two different stimuli were established as S+s for different response-outcome relations. In Experiment 1, an S+ was less effective in controlling its original response after it had undergone training as an S? for a new response that earned the same outcome than it was after training as an S? for a response that earned a different outcome. Experiment 2 established that this effect was not mediated by Pavlovian inhibitory conditioning produced by the negative correlation between the S+ and the outcome during S? training. Simply arranging a negative correlation between S+ and the outcome whose occurrence it had previously signaled did not impair the ability of that S+ to elicit its original response. In Experiment 3, the response-evoking properties of an S+ were found to be undermined by using the S+ as a signal for the simple extinction of a new response trained with the same outcome, but not with a different outcome. These results suggest that positive discriminative stimuli use their associations with the outcomes earned in their presence to control the responses that earned those outcomes.     

四川西昌泸山风景区鸟类频率指数数量等级分析及其生态分布

该文采用线路统计法,于2010年对四川省西昌泸山国家AAAA级风景名胜区鸟类调查,从调查结果计算出泸山风景区内鸟类频率指数,对鸟类频率指数数量进行等级分析。调查发现在泸山景区鸟类有7目18科59种,其中优势种7种,占11.86%,普通种8种,占13.56%,稀有种44种,占74.58%。从调查结果看,稀有种是泸山景区鸟类组成成分中的主要类群,而优势种较少。泸山的4个植被类型中,灌草丛植被中鸟类较集中;针叶林和阔叶林混交林植被中鸟类出现频率居中;阔叶林植被中鸟类出现的频率较低;农田栽培植被中鸟类分布较为广泛。     

The effects of early rearing conditions upon responses to mirror-image stimulation in domestic chicks and turkeys

Two experiments were performed in which either White Plymouth Rock chicks or domestic turkeys were reared under three maintenance conditions (with a mirror, with a conspecific, or in visual isolation) from Day 1 posthatch until Day 7. On Day 7, the Ss were given a preference test to determine whether they spent more time before a mirror or with another bird. Ss reared with a mirror spent approximately two-thirds of their time in the vicinity of the mirror, whereas socially reared Ss spent approximately two-thirds of their time with an agemate. The social isolates, on the other hand, failed to show a preference for either mirror image of conspecific stimulation. A third experiment evaluated the choice behavior of turkeys socially reared in the presence of a mirror, and revealed that, like the social isolates, these Ss also failed to exhibit a reliable preference. The results are interpreted in terms of the effects of early rearing conditions upon social stimulus preferences.