Biomedical subjects

J I Campbell

Publications and source records attributed to J I Campbell.

At least 19 recordsLinked to original sources

PubMed2001

Strategy choice for arithmetic verification: effects of numerical surface form.

Canadian university students (n=48) solved simple addition problems in a true/false verification task with equations in digit format (3+4=8) or written English format (three+four=eight). Participants reported their solution strategy (e.g. retrieval or calculation) after each trial. Reported use of calculation strategies was much greater with word (41%) than digit stimuli (26%), and this difference was exaggerated for numerically larger problems. Word-format costs on reaction time (RT) were correspondingly greater for large than for small problems, but this Format x Size RT effect was bigger for true than for false equations. The results demonstrate that surface format affects central, rather than only peripheral, stages of cognitive arithmetic.

Adult↗

PubMed2001

Cognitive arithmetic across cultures.

Canadian university students either of Chinese origin (CC) or non-Asian origin (NAC) and Chinese university students educated in Asia (AC) solved simple-arithmetic problems in the 4 basic operations (e.g., 3 + 4, 7 - 3, 3 x 4, 12 divided by 3) and reported their solution strategies. They also completed a standardized test of more complex multistep arithmetic. For complex arithmetic, ACs outperformed both CCs and NACs. For simple arithmetic, however, ACs and CCs were equal and both performed better than NACs. The superior simple-arithmetic skills of CCs relative to NACs implies that extracurricular culture-specific factors rather than differences in formal education explain the simple-arithmetic advantage for Chinese relative to non-Asian North American adults. NAC's relatively poor simple-arithmetic performance resulted both from less efficient retrieval skills and greater use of procedural strategies. Nonetheless, all 3 groups reported using procedures for the larger simple subtraction and division problems, confirming the importance of procedural knowledge in skilled adults' performance of elementary mathematics.

Achievement↗

PubMed2001

Fan effects reveal position-specific numerical concepts.

We examined associative interference (i.e., fan) effects to determine if the numerical concepts mediating numerical fact retrieval can be position specific. Participants memorized 15 "diamond arithmetic" facts (e.g., 3 [symbol: see text] 5 = 97; Whalen, 1997) involving five different operands. Ignoring operand position (i.e., left vs. right), each operand appeared equally often across items (i.e., position-independent fan was constant). In contrast, position-specific fan values varied across items (e.g., 2 appeared five times as the left operand, but once in the right position; 3 appeared four times as the left operand, and twice as the right operand, etc). Thus, we expect a fan effect only if the concepts activated by arithmetic operands are position specific. Results indicated that position-specific fan was an excellent predictor of trials to criterion, error rate, and latency. The concepts mediating number fact retrieval can be position specific.

Adolescent↗

PubMed2000

Cognitive inhibition in selection and sequential retrieval.

Inhibitory models of working memory efficiency (Engle, 1996; Zacks & Hasher, 1994) assert that individual differences in working memory reflect the efficiency of inhibitory processes that exclude irrelevant information and suppress no-longer-relevant information. The present study examined the implication that these two inhibitory processes operate at consistent levels of efficiency within individuals by examining the correlation between two cognitive inhibition effects, negative priming and negative error priming. Negative priming involves slower response to a probe-trial target that was used as a to-be-ignored distractor on the immediately preceding prime trial. Negative error priming is the phenomenon that errors in a sequence of simple arithmetic trials are unlikely to involve the correct answer to the preceding problem. Participants received distractor-target pairs of simple addition problems and were required to produce the target problem sum. Negative priming was observed for prime distractors, whereas negative error priming was observed in connection with previous targets but not distractors. Consistent with the assumptions of these working memory models, the magnitudes of the two effects were significantly correlated.

Adolescent↗

PubMed2000

Adults' strategy choices for simple addition: effects of retrieval interference.

Simple addition (e.g., 3 + 2, 7 + 9) may be performed by direct memory retrieval or by such procedures as counting or transformation. The distribution of associations (DOA) model of strategy choice (Siegler, 1988) predicts that procedure use should increase as retrieval interference increases. To test this, 100 undergraduates performed simple addition problems, either after blocks of simple multiplication (high-interference context) or after blocks of simple division problems (low-interference context). Addition took longer and was more error prone after multiplication; in particular, there were more multiplication confusion errors on the relatively easy, small-number addition problems (e.g., 3 + 2 = 6, 4 + 3 = 12), but not on the more difficult, large-number additions. Consistent with the DOA, participants reported greater use of procedures for addition after multiplication, but more so for small addition problems. The findings demonstrate that adults' use of procedural strategies for simple addition is substantially influenced by retrieval interference.

Adolescent↗

PubMed1999

The surface form x problem size interaction in cognitive arithmetic: evidence against an encoding locus.

Sixty-four university students received simple addition problems with operands presented as arabic digits (e.g. 2 + 3, 8 + 6) or as English number words (two + three, eight + six). Operands either were displayed simultaneously or sequentially with the left operand appearing 800 ms before the right operand. Consistent with previous findings, word problems were slower than digit problems and this word-format cost was larger for large- than small-number problems. The central question addressed by this experiment concerned whether this Format x Size interaction arises during problem encoding processes or in subsequent retrieval or production processes. In the simultaneous condition, both operands would contribute to format-related differences in encoding, whereas in the sequential condition encoding differences would arise only in connection with the second operand. Critically, however, the Format x Size interaction did not differ between the sequential and simultaneous conditions, although the experiment had ample power to detect such an effect. The results argue that the Format x Size interaction does not arise during encoding, but instead arises during calculation or production processes.

Adolescent↗

PubMed1999

Division by multiplication.

In two experiments, item-specific transfer was examined in simple multiplication and division with prime and probe problems separated by four to six trials. As was predicted by Rickard and Bourne's (1996) identical-elements model, response time (RT) savings were larger with identical (e.g., prime 63 divided by 7, probe 63 divided by 7) than with inverted (63 divided by 9 and 63 divided by 7) division problems, whereas identical (7 x 9 and 7 x 9) and inverted (9 x 7 and 7 x 9) multiplication problems produced equivalent transfer. Nonetheless, there was statistically significant transfer between inverted division problems. Furthermore, RT savings in the multiplication-to-division transfer conditions (e.g., prime 7 x 9, probe 63 divided by 7) indicated that multiplication mediated large-number division problems. These latter effects are not predicted by the identical-elements model but may be reconciled with the model by distinguishing associative transfer (facilitation owing to strengthening of a common problem node in memory) from mediated transfer (facilitation owing to mediation by a strengthened, related problem). Skilled adults can exploit the conceptual correspondences between multiplication and division facts in a highly efficient way to facilitate performance.

Adult↗

PubMed1998

Linguistic influences in cognitive arithmetic: comment on Noel, Fias and Brsybaert (1997)

Noël et al. (Noël, M.-P., Fias, W., Brsybaert, M., 1997. About the influence of the presentation format on arithmetical-fact retrieval processes. Cognition 63, 335-374) examined the simple-multiplication errors of 24 Dutch- and 24 French-speaking adults for evidence that number reading interferes with language-specific, number-fact retrieval processes. They concluded that arithmetic memory is not influenced by reading-based interference and is based on a notation and language-independent mental representation. Alternative analyses of their error data, however, provide strong evidence that arithmetic performance is subject to reading-based interference and provide some support for the language-specificity of number-fact memory.

Adult↗

PubMed1997

On the relation between skilled performance of simple division and multiplication.

Are corresponding multiplication and division facts (e.g., 7 x 8, 56 divided by 7) based on common or on independent memory processes? University students received division problems alternated with multiplication problems under instructions for speeded responses. Response times were highly correlated for corresponding division and multiplication problems, and error characteristics indicated parallel retrieval structures. Specifically, division errors were constrained by the distance between the dividend and the product implied by the error, rather than by distance from the correct quotient. This suggests that division memory is organized in terms of multiplicative relationships. Multiplication errors (e.g., 7 x 9 = 56) were primed by previous division trials (56 divided by 7 = 8), but division errors were not primed by previous multiplications. The error priming results suggest that multiplication is often used at least to check division.

Adolescent↗

PubMed1997

Reading-based interference in cognitive arithmetic.

Do number-fact retrieval (4.6 =?) and numeral reading (e.g., transcoding 46 into "forty six") access the same retrieval structures? Data from the present experiment suggest that they do. Under instructions to respond quickly, adults performed simple multiplication problems oriented horizontally or vertically with operands presented simultaneously or with a 500 ms preview of one operand. Errors involving congruent operand intrusions (e.g., 2.8 = 24 or 9.6 = 36) were most frequent when conditions afforded the left-to-right encoding sequence that is standard for reading multi-digit numbers. Ninety percent of such intrusions involved the correct answer to another simple multiplication problem (e.g., 4.8 = 28) rather than a miscellaneous answer (e.g., 4.8 = 38). This high rate of arithmetically related intrusions suggests that numeral reading and verbal production of number facts involve a shared representational system.

Adolescent↗

PubMed1997

Pseudomonas aeruginosa isolates from patients with cystic fibrosis have different beta-lactamase expression phenotypes but are homogeneous in the ampC-ampR genetic region.

Pseudomonas aeruginosa isolates from 1 of 17 cystic fibrosis patients produced secondary beta-lactamase in addition to the ampC beta-lactamase. Isolates were grouped into three beta-lactamase expression phenotypes: (i) beta-lactam sensitive, low basal levels and inducible beta-lactamase production; (ii) beta-lactam resistant, moderate basal levels and hyperinducible beta-lactamase production; (iii) beta-lactam resistant, high basal levels and constitutive beta-lactamase production. Apart from a base substitution in the ampR-ampC intergenic region of an isolate with moderate-basal-level and hyperinducible beta-lactamase production, sensitive and resistant strains were identical in their ampC-ampR genetic regions. Thus, enhanced beta-lactamase expression is due to mutations in regulatory proteins other than AmpR.

Chronic Disease↗

PubMed1996

Inhibitory processes in sequential retrieval: evidence from variable-lag repetition priming.

Performance of simple mental arithmetic provides a sensitive measure of subtle inhibitory and excitatory processes operating in sequential retrieval. Specifically, the probability that an error (e.g., 6 x 7 = 36) matches an earlier answer is below chance for the preceding trial (negative error priming), greater-than-chance for intermediate lags (positive error priming), and returns to chance after about 10 intervening trials (approximately 60 sec) (Campbell & Clark, 1989). Negative error priming suggests that inhibitory processes initially suppress just-produced items and temporarily mask excitatory effects of recent retrievals. To test further the inhibition hypothesis of negative error priming, we examined repetition priming effects at variable lags. The results demonstrate similar non-monotonic functions for error priming and repetition priming as a function of lag, consistent with the hypothesized decay of inhibitory memory processes.

Adolescent↗

PubMed1996

Retrieval processes in arithmetic production and verification.

To investigate whether arithmetic production and verification involve the same retrieval processes, we alternated multiplication production trials (e.g., 9 x 6 = ?) with verification trials (4 x 9 = 36, true or false?) and analyzed positive error priming. Positive error priming is the phenomenon in which errors frequently match correct answers from preceding problems. Production errors were strongly primed by previous production trials (the error-answer matching rate was about 90% greater than expected by chance), but production errors were not strongly primed by previous verification trials (approximately 13% above chance). Conversely, false-verification errors were primed by previous verification trials (approximately 25% above chance), but not by production trials. The results indicated that arithmetic production and verification were mediated by different memory processes and suggest a familiarity-based over a retrieval-based model of arithmetic verification.

Adolescent↗

PubMed1994

Architectures for numerical cognition.

Current theories of numerical cognition differ in assumptions about the componential architecture of number processing and about the extent of notation-specific processes. To investigate these issues, 64 adult subjects were tested on simple addition and multiplication problems presented in Arabic digit or English number-word format. Overall, response times and error rates were much higher with the word format, but more importantly, presentation format interacted with arithmetic operation and problem size. Operation errors (2 + 4 = 8), operand-naming errors (2 + 8 = 8), and operand-intrusion errors (9 x 6 = 36) were each characterized by a different format x operation interaction, and analysis of inter-trial error priming showed selective interference from preceding trials as a function of number format. These types of format-specific retrieval interference and operation-specific effects of format are problematic for models that hypothesize notation-independent memory processes for arithmetic. Furthermore, analyses of operand-naming errors, operand-intrusion errors, and other operand-priming effects, revealed strong interactions of number reading and number-fact retrieval processes; processes that are typically posited to be functionally independent. The results suggest a complex encoding architecture that incorporates notation-dependent activation of addition and multiplication facts, as well as interpenetration of number reading and number-fact retrieval processes.

Adult↗

PubMed1992

Network interference and number-fact retrieval: evidence from children's alphaplication.

The origins of several phenomena of number-fact retrieval were investigated by having children in Grades 3 and 4 memorize alphaplication facts (arithmetic-like memory items composed of letters instead of numbers). Alphaplication performance paralleled memory for arithmetic facts in several important respects: Results showed (a) a large performance advantage for tie (e.g., E, E = j) over nontie problems (E, I = p), (b) that most errors involved answers from the correct alpha-table, (c) that response times and error rates were strongly correlated across problems, (d) that the correct answers to poorly learned problems tended to be the most common error responses, and (e) that performance was lower for problems introduced later in the learning sequence. Taken together, these findings support a network-interference approach (Campbell & Graham, 1985) to memory for arithmetic facts.

Attention↗

PubMed1991

Integrated versus modular theories of number skills and acalculia.

This paper contrasts two views of the cognitive architecture underlying numerical skills and acalculia. According to the abstract-modular theory (e.g., McCloskey, Caramazza, & Basili, 1985), number processing is comprised of independent comprehension, calculation, and production subsystems that communicate via a single type of abstract quantity code. The alternative, specific-integrated theory (e.g., Campbell & Clark, 1988), proposes that visuospatial, verbal, and other modality-specific number codes are associatively connected as an encoding complex and that different facets of number processing generally involve common, rather than independent, processes. The hypothesis of specific number codes is supported by conceptual inadequacies of abstract codes, format-specific phenomena in calculation, the diversity of acalculias and individual differences in number processing, lateralization issues, and the role of format-specific codes in working memory. The integrated, associative view of number processing is supported by the dependence of modular views on abstract codes and other conceptual inadequacies, evidence for integrated associative networks in calculation tasks, acalculia phenomena, shortcomings in modular architectures for number-processing dissociations, close ties between semantic and verbal aspects of numbers, and continuities between number and nonnumber processing. These numerous logical and empirical considerations challenge the abstract-modular theory and support the encoding-complex view that number processing is effected by integrated associative networks of modality-specific number codes.

Humans↗

PubMed1991

Conditions of error priming in number-fact retrieval.

Analysis of errors in simple multiplication has shown that answers retrieved on previous trials are initially inhibited (negative error priming) but later are promoted as errors to subsequent problems (positive error priming). Two experiments investigated whether error priming is associated either with problem-specific retrieval processes or with representations of answers that can be manipulated independently of problems. In Experiment 1, answers were primed by visually presenting products for 200 msec prior to problems. Correct-answer primes facilitated retrieval, related-incorrect primes interfered with retrieval more than unrelated primes, and both effects were greater for more difficult problems. Primes affected only the trial on which they were presented, however, whereas both negative and positive error priming from previous problems were observed across trials. In Experiment 2, subjects named and retrieved multiplication products on alternating trials. Just-named products were inhibited as errors to the following multiplication problem (i.e., negative error priming), but, compared to positive priming from previous retrieved products, positive error priming from previously named numbers was weak. The results indicate that positive error priming is due mainly to an encoding or retrieval bias produced by previous problems, whereas negative error priming entails suppression, or de-selection, of answer representations.

Adolescent↗

PubMed1990

A recombinant fowlpox virus expressing the hemagglutinin-neuraminidase gene of Newcastle disease virus (NDV) protects chickens against challenge by NDV.

The hemagglutinin-neuraminidase (HN) gene from the Beaudette C strain of Newcastle disease virus (NDV) has been expressed in a recombinant fowlpox virus vector. The HN gene, under the control of the vaccinia p7.5 promoter, was inserted into a nonessential gene in the terminal inverted repeats of fowlpox virus. Expression was demonstrated in tissue culture, a protein of the correct size for fully glycosylated HN protein being recognized by an HN-specific monoclonal antibody on Western blots. When the recombinant fowlpox virus was inoculated into chickens by intravenous or wing-web routes, antibody which recognizes HN from purified NDV virions was produced. Protective immunity to NDV was generated in the chickens; at the highest dose of vaccine 100% of the chickens tested were protected against challenge with a virulent strain of NDV.

Animals↗