The Effect of Word Length on Immediate Serial Recall Depends on Phonological Complexity, Not Articulatory Duration

Immediate recall for sequences of short words is better than for sequences of long words. This word-length effect has been thought to depend on the spoken duration of the words (Baddeley, Thomson, & Buchanan, 1975) or their phonological complexity (Caplan, Rochon, & Waters, 1992). In Finnish both vowel and consonant quantity distinguish between words. Long phonemes behave like phoneme repetitions. In Experiment 1, subjects were presented with auditory lists of three kinds of pseudowords based on Finnish phonotactics: short CVCV-structures (e.g. / tepa/ ), long two-syllable items with long phonemes (e.g. / te: p: a / ), and long three-syllable items with CVCVCV structures (e.g. / tepalo / ). Although both kinds of long stimuli (of identical spoken length) took longer to read, only three-syllable items were more difficult to remember than the short stimuli. Experiment 2 contrasted the effect of number of syllables with number of different phonemes. The long two-syllable items were replaced by two-syllable items of equal spoken duration but containing six different phonemes (e.g. / tiempa / ). These two-syllable items were as difficult to recall as were the three-syllable items. Experiment 3 controlled for the possibility that long stimuli might be rehearsed in a shorter form. It is concluded that aspects of phonological complexity are critical for word-length effects. Implications of this finding for working memory theory are discussed, and future work based on multi-layered phonological representations is proposed.     

Memory of a speaker's voice: Reaction time to same- or different-voiced letters

Subjects were presented with a sequence of two letters, each letter spoken in either a male or female voice. On each trial, the subject was required to indicate, as quickly as possible, whether the two letters had the same name. Reaction times (RTs) were faster for letters spoken in the same voice for both “same” and “different” responses, even when letters were separated by 8 s. These results are incompatible with the notion of physical and name codes in auditory memory since a “different” response should always be based on a comparison of letter names and should not be influenced by voice quality. It was also found that RTs were not influenced by the phonemic distinctive feature similarity of the letters.     

Inducing a Rule in Wason's 2-4-6 Task: A Test of the Information-Quantity and Goal-Complementarity Hypotheses

In the standard 2-4-6 induction task, subjects are instructed to discover the rule generating sequences of three numbers by inventing number triples for which they receive immediate feedback. The rule is “ascending numbers”. Performance is greatly aided with Dual Goal (DG) instructions that ask subjects to discover two rules, one that generates “Dax” triples (equivalent to “yes” instances with Single Goal [SG] instructions) and another that generates “Med” triples (equivalent to “no” instances). The present study eliminates two explanations for this effect suggested by Wharton, Cheng, and Wickens (1993). Experiment 1 tested their Information-Quantity hypothesis that the effect results simply from the DG subjects testing more triples prior to proposing a rule. Our DG subjects were more likely to solve the problem and produced more “negative” triples than SG subjects when both groups generated exactly 15 triples. Two further groups received feedback only after generating all 15 triples, and again DG subjects were more likely to solve the problem and to generate more “negative” triples. Experiment 2 tested Wharton et al.'s Goal-Complementarity hypothesis that success under DG instructions hinges on preserving the complementary representation of the two rules. We compared SG instructions with three types of DG instructions that suggested different types of triples (Dax, Med, both Dax and Med, neither Dax nor Med). DG instructions were more effective in promoting successful rule discovery regardless of differences in rule complementarity. Our analysis of the heterogeneity of the examplars generated with DG instructions in both experiments suggest that success on the 2-4-6 task is as much a consequence of the breadth of hypotheses that subjects entertain as it is a consequence of the testing strategy.     

Reversal learning by fornix-transected monkeys

Experiment 1 examined visual reversal learning and in Experiment 2 monkeys were trained to criterion in a serial reversal set between “FR” and “DRO” response requirements. In both cases impairments were observed in fornix-transected monkeys. These results are discussed in connection with previous findings that in serial reversals damage to the hippocampal system in monkeys causes a deficit in spatial but not in visual learning. A unified account is proposed.     

When do auditory/visual differences in duration judgements occur?

Four experiments examined judgements of the duration of auditory and visual stimuli. Two used a bisection method, and two used verbal estimation. Auditory/visual differences were found when durations of auditory and visual stimuli were explicitly compared and when durations from both modalities were mixed in partition bisection. Differences in verbal estimation were also found both when people received a single modality and when they received both. In all cases, the auditory stimuli appeared longer than the visual stimuli, and the effect was greater at longer stimulus durations, consistent with a “pacemaker speed” interpretation of the effect. Results suggested that Penney, Gibbon, and Meck's (2000) “memory mixing” account of auditory/visual differences in duration judgements, while correct in some circumstances, was incomplete, and that in some cases people were basing their judgements on some preexisting temporal standard.     

Remembering, Familiarity, and Source Monitoring

Two experiments investigated recollective experience in a source monitoring task. Subjects saw an array of objects and performed, watched, or imagined actions involving pairs of objects. In a subsequent recognition test, subjects indicated whether their recognition judgements were made on the basis of conscious recollective experience (“remember” responses), or on some other basis such as familiarity (“know” responses). The proportions of correct “remember” responses for both objects and actions decreased from performed, through watched, to imagined actions, whereas the proportions of correct “know” responses were uninfluenced by the source of the memories. In addition, the relationship between recollective experience and accuracy of source judgement varied across sources. Source accuracy for performed actions was obtained only in “remember” responses, whereas source accuracy for imagined actions was obtained only in “know” responses. Source accuracy for watched actions was obtained in both “remember” and “know” responses. The findings suggest that the types of memory attributes available at retrieval determine the quality of subsequent memory experience, and it is proposed that memories with strongly self-referential attributes (arising from performed actions) powerfully cue recollective experience during retrieval.     

Intelligence tests on trial: An “interview” with judges Robert F. Peckham and John F. Grady

The issue of culturally biased intelligence tests has been heard in two federal courts. Judge Robert F. Peckham, in the Larry P., et al. v. Wilson Riles, et al. case, ruled that intelligence tests were culturally biased. In contrast, Judge John F. Grady, in the Parents in Action on Special Education, et al. v. Joseph P. Hannon, et al. case, ruled that intelligence tests were not culturally biased. A mock “interview” based on the judges' written opinions, shows similarities and differences in their approach to various issues involved in the trials.     

Age-related declines in context maintenance and semantic short-term memory

This study reports age-related declines in context maintenance (Braver et al., 2001) and semantic short-term memory (STM) and evidence for a relation between the two. A group of younger and older adults completed a context maintenance task (AX-CPT), a semantically oriented STM task (conceptual span), a phonologically oriented STM task (digit span), and a meaning integration task (semantic anomaly judgement). In the AX-CPT task, a target response is required to the probe letter “X” but only when it is preceded by the letter “A” (the context). Either three (short interference) or six distractor letters (long interference) were presented between the cue and the probe. Results indicated an age-related deficit in context maintenance. Age-related declines were also observed for conceptual span and semantic anomaly judgement but not for digit span. Context maintenance was correlated with conceptual span and semantic anomaly judgement but not with digit span. These correlations were largely mediated by age differences, which also explained variance that was unique to (and not shared among) context maintenance, conceptual span, and semantic anomaly judgement.     

A study of the effect of structural information and familiarity in form perception

Two experiments were carried out to investigate the influence of structural information and familiarity on the processing of visual forms. Pairs of “well” structured and nameable and “poorly” structured and non-nameable fragmented forms were employed as stimuli. The effects of structure and familiarity were assessed by manipulating the visual hemifield of presentation and the task. In Experiment 1 stimuli were judged as being either in the same orientation or mirror-reversed, a task that does not require high-level semantic information to be processed. Experiment 2 required physically identical forms to be matched, which may use either physical or name information. In Experiment 1 “same” judgements were equivalent for both types of stimuli, and “different' judgements were longer for the “poorly” structured (non-nameable) forms. In Experiment 2 there was little overall difference between “well” and “poorly” structured forms, though response times to “well” structured (nameable) forms were slowed for right-visual-field presentations. It is suggested that familiarity may not be sufficient to provide a perceptual advantage for nameable forms, as the advantage for nameable stimuli was confined to “same” judgements in Experiment 1 and response times were shorter for non-nameable stimuli in Experiment 2. Rather, performance depends upon factors such as the computation of global shape (due to structural properties of collinearity and closure) and on the use of different kinds or representations (physical versus name) in matching.     

The phonological store abandoned

Baddeley and Larsen (2007) argue that a number of key findings reported by Jones, Macken, and Nicholls (2004) and Jones, Hughes, and Macken (2006) pointing to shortcomings of the phonological store construct arise from the store being abandoned with long lists. In our rejoinder we point out that Baddeley and Larsen use a procedure in which retrieval from the supposed phonological storage would not—according to their own theory—have been possible, and we present theoretical, empirical, and logical problems with their “store abandonment” argument and highlight a number of difficulties associated with the interpretation of suffix and prefix effects. We conclude that our data are still problematic for the phonological store construct and suggest that a reformulation of short-term memory theory needs to embody (or indeed focus exclusively upon) perceptual and effector systems rather than bespoke storage modules.     

Evaluation and elimination of an avoidance response in a child who stutters: A case study

In this case study, efforts to treat stuttering in a 6-year-old male with cerebral palsy were complicated by frequent replies of “I don't know” that allowed the child to avoid more extensive answers to conversational questions. Following a program of extinction plus differential reinforcement of alternative behavior (DRA), the response “I don't know” was decreased while both speech rate and stuttering increased. Simplified habit reversal (SHR) techniques (controlled breathing) were then applied and resulted in a reduction of stuttering and maintenance of low rates of avoidance. A reversal to baseline resulted in initially high levels of avoidance and low levels of stuttering, with these trends reversing as baseline continued. The SHR treatment for stuttering was then reimplemented and stuttering rates again decreased while avoidance rates remained low, Implications are discussed.     

Acoustic factors in visual search

Previous work has shown that in searching for existing or absent “e.s” in printed prose, the presence or absence of silent “e.s” was less likely to be detected than that of pronounced “e.s.” It was suggested that the acoustic or kinaesthetic “image” was searched for evidence of an “e” in addition to the visual stimulus and that evidence from both sources was considered in making the appropriate response.

The present experiment employs mainly substitutive errors within words, which may or may not change their pronunciation. The results suggest that the form of the acoustic correlates has no bearing upon whether the words are detected as wrongly spelt, but that the presence or absence of an acoustic event corresponding in time to the spatial location of the error is important.     

Concrete and abstract terms and relations in testing a rule

Subjects have more difficulty in correctly testing a conditional rule stated in abstract form than the same rule given in “thematic” form. The “thematic” form of the rule involves both concrete terms and a concrete relation. Four experimental conditions were formed by combining concrete abstract terms and relations. Fifty subjects were tested in each condition. The results indicated that concrete-ness of the terms is the main factor leading to improved performance with “thematic” as against abstract material in the rule testing task.     

The cholinergic neurotransmitter system in human memory and dementia: A review

The present paper reviews three types of evidence implicating the role of acetylcholine in human memory and dementia: (1) neuropathological evidence that the cholinergic transmitter system is depleted in Alzheimer-type dementia; (2) psychopharmacological studies that have employed “cholinergic blockade” as a model of cholinergic depletion; and (3) clinical studies of cholinergic “replacement” therapy in Alzheimer-type dementia. The evidence that the cholinergic system is depleted in Alzheimer-type dementia has been complemented by the finding that cholinergic blockade in healthy subjects causes a substantial learning (or “acquisition”) deficit in episodic memory. The overall results of studies of replacement therapy have generally been disappointing, but a few have reported benefits in recall and recognition tests. The role of the cholinergic system in many aspects of memory remains to be elucidated; but it seems unlikely that cholinergic depletion accounts for all aspects of the memory disorder in Alzheimer-type dementia, and possibly the depletions of other neurotransmitters also contribute to the memory impairment.     

Cue location does not account for all selective associations in food aversion learning

Studies of food aversion learning have been widely interpreted as yielding evidence for selectivity in the associability of cues and consequences. On the one hand, taste cues were easily conditioned to interoceptive consequences (e.g. “illness”), but only with difficulty to exteroceptive consequences (e.g. shock). On the other hand, audiovisual stimuli were easily conditioned to shock, but only with difficulty to illness (Revusky and Garcia, 1970). Sullivan (1984) has emphasized that cue location and temporality have been important uncontrolled variables in many food-aversion studies and has argued that when these factors are taken into account, the supposed selectivity related to sensory modality is lost. Thus, Sullivan (1984) argues that shocks, like “illness”, are readily associated with tastes provided that the tastes are intrinsic attributes of the substances ingested.

Sullivan's important article may have demonstrated significant weaknesses in the evidence for specific associations of exteroceptive cues with shock rather than with “illness”, and this point will not be considered further. However, there are two aspects of Sullivan's case that cannot be substantiated. Firstly, the attempt to demonstrate that taste cues are as readily associated with shock as they are with “illness” is unconvincing. Secondly, unjustified assumptions are made about the nature of the unconditioned stimulus in conditioning with interoceptive consequences, which is presumed to be “illness” despite extensive evidence to the contrary.     

Adaptation to displaced vision: Reafference is a special case of the cue-discrepancy hypothesis

Subjects were exposed to a prismatically displaced view of their actively-moved right hand which was optically “stopped”; they achieved as much adaptation in this condition as in one in which they were allowed full “reafferent” stimulation. This provides further evidence against Held's “reafference“ hypothesis.     

Temporal factors in pattern vision

A sequence of uncorrelated randomly patterned visual stimuli (“visual noise”) is normally seen as a field of particles in “Brownian motion.” When each frame of the sequence is followed by a blank flash superimposed on the same region of the visual field, the apparent structure of the noise field is strikingly altered, its form varying with the time interval between frame and flash. At a critical interval, many dots seem to cohere, to form maggot-like objects.

Some of the factors determining this critical interval have been studied. They include the brightness, repetition frequency and exposure duration of the noise field, and the distance of its retinal image from the fovea.

The critical interval for “perceptual blanking” is quite different from that for the “maggot effect,” but the two show a suggestively similar dependence upon the duty cycle of the noise display.

It is of some neurological interest that the phenomenon is not appreciably visible with dichoptic mixing of noise and blank stimuli.     

Articulatory and Phonological Determinants of Word Length Effects in Span Tasks

Several previous studies have shown that memory span is greater for short words than for long words. This effect is claimed to occur even when the short and long words are matched for the number of syllables and phonemes and so to provide evidence for subvocal articulation as being one mechanism that underlies memory span (Baddeley, Thomson, & Buchanan, 1975). The three experiments reported in this paper further investigate the articulatory determinants of word length effects on span tasks. Experiment 1 replicated Baddeley et al.'s finding of an effect of word length on auditory and visual span when the stimuli consist of words that differ in terms of the number of syllables. Experiments 2 and 3 showed that the effects of word length are eliminated when the words in the span task are matched for the number of syllables and phonemes but differ with respect to the duration and/or complexity of their articulatory gestures. These results indicate that it is the phonological structure of a word and not features of its actual articulation that determines the magnitude of the word length effect in span tasks.     

Visual pattern recognition: Size preprocessing re-examined

Template theories of visual pattern recognition assume the operation of preprocessing routines to deal with irrelevancies such as discrepancies in stimulus size. In three experiments where size was an irrelevant dimension, observers classified pairs of forms as either “same” or “different”. In Experiment I, the classification “different” was required when the stimuli shared the same form but a different orientation, and “same” when the stimuli shared the same form and orientation. Under these conditions RT was an increasing function of the magnitude of the size disparity between stimuli with equal slopes for “same” and “different” judgements. In Experiment II, “different” classifications were made to stimuli that had different forms, and “same” to figures with the same form. This stimulus set produced a size disparity function that interacted with response type; “different” responses had a shallower slope. Experiment III consisted of a mixed stimulus set drawn from both Experiment I and II. Stimuli that produced additive effects of size disparity and response type in Experiment I now produced an interaction between these two factors similar to the one observed in Experiment II. The results of these experiments are interpreted as evidence that previous contradictory results reported in the literature stem from differences in the way the stimulus set is constructed, and that size transformations can not be a necessary operation, at least when “different” judgements are made. The results are problematic for the view that size disparity effects in matching tasks are easily interpretable in terms of a primitive size normalization stage that precedes any comparison operations.     

Performance or capacity, the model still requires definitions and boundaries it doesn't have

Siegel is correct that, in its current form, the specific constructs underlying the Demands and Capacities Model cannot be adequately defined. However, substituting observable behavior (performance) for presumed underlying weaknesses in the speech production systems of those who stutter (capacity) does not appear to solve the problem of circularity identified. Rather, demands have not been adequately defined, either.

There is much to agree with in Siegel's note. However, it is not clear to me that the Demands and Capacities Model is salvaged by substituting the term “Performance” for “Capacity.” Rather, the problem with the Model is one of defining terms precisely enough so that the Model is not circular (as Ingham & Cordes (1997) have noted), or the logical inverse of Procruste's bed, as I have stated elsewhere (Bernstein Ratner, 1997), a model that fits all interpretations simply because it stretches to fit all possibilities.