bluuebunny/crossref_metadata_2025 huggingface dataset:
Forgetting as a Function of Sleep at Different Times of Day
Authors: Hockey G. R. J. , Davies S. , Gray M. M.
Published: July 2007

The experiment studied the separate effects of sleep and time period of retention interval on forgetting. A free recall task was given to independent groups of subjects either at night or in the morning, and a second recall demanded 5 h later, after an intervening period of sleeping or waking activity. Oral body temperatures (BT) were measured at each session. The data were analysed in terms of (a) immediate recall at test 1, and (b) amount forgotten from test 1 to test 2. Immediate recall was higher for morning groups, in agreement with previous findings, serial position analysis indicating that the effect is confined to enhancement of the primary memory component. Long-term retention was higher over the night interval, irrespective of sleeping conditions, though having slept at night produced better retention than having stayed awake. Sleep during the morning was not effective in reducing forgetting. BT showed a marked drop for both night groups and rise for day groups over the retention interval. Alternative explanations for the classical sleep/memory findings are suggested in terms of (a) differential effects of sleep stages on memory, and (b) the underlying diurnal variation in BT and other processes.
The Disruptive Effect of an Irrelevant Message in Dichotic Listening to Word-Lists
Authors: Holloway C. M.
Published: July 2007

The results of previous experiments suggest that when listeners are asked to repeat back prose arriving at one ear, their performance is unaffected by the presence (in the other ear) of another independent prose passage in the same voice and of equal intensity. In the present study dichotic messages were employed in which the words were presented quasi-simultaneously and were not connected in meaning. Considerable performance decrement was found from a message on the irrelevant ear even if that message was less intense than that on the relevant ear. Different kinds of error occur, but the principle form of error is a response which is incorrect but nevertheless clearly related to the word presented to the relevant ear. The results extend the findings of Treisman (1967, 1970) who found considerable interference in dichotic listening to pairs of words exactly matched for time of onset; and suggest a general difficulty of selective attention when non-prose material is used.
Personality in Monkeys: Factor Analyses of Rhesus Social Behaviour
Authors: Chamove A. S. , Eysenck H. J. , Harlow H. F.
Published: July 2007

Three factor analyses were performed on social interaction data from 168 juvenile macaques. Animals were tested in stable quadrad peer groups; in newly-formed dyads with infant, juvenile, and adult stimulus monkeys; and in similar triads with the stimulus animal plus a familiar cage-mate. Factors emerged, most strongly in the most stable condition, which were interpreted as affiliative, hostile and fearful. These factors were almost entirely independent and resembled the extraversion, psychoticism, and emotionality factors frequently found in humans.
Characteristics of Visual and Proprioceptive Response Times in the Learning of a Motor Skill
Authors: Jordan Timothy C.
Published: July 2007

After an identical pre-training period 36 subjects were randomly assigned to one of three treatment groups (visual, visual and proprioceptive, proprioceptive, i.e. blindfold) on a motor task. All subjects received three different forces of the stimulus (blade deflection) in a random but balanced fashion. Following 10 training sessions, blindfold subjects had significantly faster RTs. Total response times (RT + MT) were also faster. The three stimulus forces presented produced significant differences in both RT and MT. No differences, however, were found for total response times; a descriptive analysis revealed a step function. As the force increased RT decreased, the opposite effect being observed for MT. Central and peripheral factors were discussed in relation to this phenomenon.
Contingency Theory and the Distinction between Associative and Non-Associative Effects in Classical Conditioning
Authors: Sheldon M. H.
Published: July 2007

There is evidence to suggest that CS-US contingency is the variable that determines the associative effects of a CS. It has been claimed that experiments where contingency is manipulated allow us to distinguish between excitatory and inhibitory associative effects, and suggest a solution to the problem of finding a control procedure for non-associative effects. It is argued, however, that unless we can find a priori grounds for defining a level of contingency at which there are no associative effects, these claims are not justified. The reasons for this are that we have no way of distinguishing experimentally between associative and non-associative contributions to the effect of a CS, and that without such a technique there is no possibility of locating the point of associative neutrality empirically.
Temporal Characteristics in Apparent Movement: Omega Movement vs. PHI Movement
Authors: William Tyler C.
Published: July 2007

A vertical line stimulus was presented alternately at two positions on an oscillo scope face, with no interstimulus interval. Observation of this stimulus produced haphazard alternation between a number of movement percepts, which were divided into four categories: phi, omega and partial movement, and no movement. Attention to one category did not increase the proportion of time movement in that category it was reported. Proportion of time reported for each category varied differentially as a function of alternation frequency. Upper and lower displacement amplitude limits were measured as a function of frequency for phi and omega movement. Both limits for omega movement differed from those for phi movement. The results imply that phi and omega movement involve separate processing stages in the visual system.
The Relation between Physical Stimulus Properties and the Effect of Foreperiod Duration on Reaction Time
Authors: Sanders A. F. , Wertheim A. H.
Published: July 2007

Seven subjects were used in an experiment on the relation between signal modality and the effect of foreperiod duration (EP) on RT. With visual signals the usually reported systematic increase of RT as a function of FP duration (1, 5 and 15 s) was confirmed; with auditory signals no difference was found between FP's of 1 and 5 s while the effect at 15 s was equivalent to that found at 5 s with the visual signal. The results suggest that besides factors such as time uncertainty the FP effect is also largely dependent on the arousing quality of the signal.
Phonemic Stage Not Necessary for Reading
Authors: Baron Jonathan
Published: July 2007

Subjects can classify, as not making sense, phrases which sound as though they make sense, e.g. “tie the not”, as quickly as other phrases which do not even sound right, although they make more errors on the former. When asked whether or not phrases sound sensible regardless of how the phrases look, they are faster and make fewer errors on the phrases that look sensible as well as sound sensible. It is concluded that meaning can be efficiently derived from a visual analysis of text without the use of an intermediate phonemic code, or “inner speech”, although such a code may be used some of the time.
Inter-Stimulus Interval and the Rate of Behavioural Habituation
Authors: File Sandra E.
Published: July 2007

A series of 10 tone stimuli was presented to rats at intervals of 1/4, 1/2, 1, 1 1/2, 2, 2 1/2, or 3 min or 24 h. The next day a test tone was presented and the distraction to this measured. There was less habituation (i.e. greater distraction) at shorter inter-stimulus intervals, but this effect asymptoted at 2 min and thereafter there was no further increase in habituation, even with inter-stimulus intervals of 24 h. A second independent variable was the stimulus duration which did not affect the rate of habituation, nor did it interact in any way with the inter-stimulus interval.
The Delayed Stimulus Suffix Effect following Arhythmic Stimulus Presentation
Authors: Crowder Robert G.
Published: July 2007

In auditory memory span experiments an extra word presented at the end of the list impairs performance on the last few items even though it is completely redundant; delaying this stimulus suffix past the time when an additional memory item would have occurred–-so that the rate of presentation is retarded for the suffix–-reduces the magnitude of the performance impairment. One account of this pattern of results is that during presentation of the items the subject adjusts periodic bursts of attention to the regular cadence of new information. Since an immediate suffix is in time with this cadence and a delayed suffix not, the larger effect of the former is explained without appeal to any process dependent on real time. In the present study the stimulus items were presented in an arhythmic manner with interstimulus intervals ranging from 100 to 900 ms on a random basis. Under these conditions the same effect of delaying the suffix was observed as is typical of rhythmic stimulus presentation; therefore, the rhythm hypothesis for the effect is not supported.
Some Experiments Relating to the Perception of Complex Tones
Authors: Moore B. C. J.
Published: July 2007

Pattern recognition models for the perception of complex tones assume that the pitch of a complex tone is derived from more primary sensations, such as the pitches of the individual partials. Thus a complex tone will only have a well-defined pitch when at least one partial in the complex is separately perceptible. Models based on time-interval measurements, on the other hand, require an interaction of the original components, so that the periodicity of the input waveform is preserved. In Experiment I the relative intensity of a “target” tone, necessary for its identification in the presence of either one or two “masking” tones, was determined, over a range of frequencies. This intensity changes abruptly at around 5 kHz, a result consistent with the idea that the pitches of pure tones are determined by temporal mechanisms for frequencies up to 5 kHz, and by place mechanisms for frequencies above this. In Experiments II and III the audibility of the partials in a multi-tone complex was measured as a function of their frequency separation and compared with the range of conditions over which a complex stimulus produced a clear pitch sensation, using the same set of subjects in each experiment. It was found that under some conditions the complex had a well-defined pitch when none of the individual partials was separately audible. This is contrary to the predictions from the pattern recognition models. The effects of masking noise in the frequency region below the complex, and the results of individual subjects, also did not conform with the predictions from these models. Such models are not ruled out, however, for low harmonic numbers, or for stimuli containing only a small number of partials.
Does Intermodal Equivalence Exist between Heteromodal Stimulus Dimensions or between Stimulus Values on those Dimensions?
Authors: Harvey Nigel
Published: July 2007

In a same—different judgement task with successively presented signals, subjects matched dots in different vertical positions and tones of different frequencies intramodally and intermodally. The first and second stimuli of trials in each of the four modality conditions were drawn from a set consisting of two, three or five alternatives. In all intermodal set size conditions, the dimensions of pitch and vertical position were related by the same equivalence rule. While intramodal performance improvement depended only on the total number of practice trials at matching on the relevant dimensions, intermodal performance improvement appeared to be related to the number of trials practice with each heteromodal stimulus pairing in a particular set. After performance had approached asymptotic level neither intramodal nor intermodal matching reaction time depended on set size. Mean “same” reaction time was less than mean “different” reaction time, and this difference was greater for intermodal matching than for intramodal matching. The results indicated that intermodal equivalence exists between discrete stimulus values on heteromodal dimensions rather than between the dimensions themselves.
A Comparison of Continuous and Distributed Reduced Sleep Schedules
Authors: Hartley L. R.
Published: July 2007

After a night of normal sleep, 36 subjects were divided into three groups of 12. One group was allowed to continue sleeping normally, one group had four hours continuous sleep and the third group had three 80-min periods of sleep distributed throughout the 24-h period, for the next four days. Subjects were given a visual vigilance test on each day. Overall performance was rather better following distributed than following continuous reduced sleep, but rather worse than following 8 h of sleep. The main difference between the reduced sleep groups was in their decision criterion. It was suggested that this difference mainly reflected the difference in time since the two groups had last slept.
Transfer after Pretraining with the Negative Stimulus
Authors: Hall Geoffrey
Published: July 2007

Two groups of rats trained in the jumping stand acquired a horizontal stripes vs. vertical stripes discrimination and then learned its reversal. The groups differed in their pretraining. One group had previously learned a black vs. white discrimination; the other a discrimination in which the S- was the same as that used in the horizontal against vertical problem. S- pretraining facilitated not only acquisition but also the reversal of the orientation discrimination thereby confirming a prediction that reversal learning will be rapid when the original problem is learned chiefly in terms of the S-. It is suggested that overtraining may facilitate reversal learning, in some cases at least, by inducing animals to concentrate on the S-.
Adaptive Changes of opposite Sign in the Oculomotor Systems of the Two Eyes
Authors: Craske Brian , Crawshaw Martin
Published: July 2007

Subjects inspected their feet via base-out prisms for 3 min. Using binocular vision, subsequent reaching without prisms showed significant overestimation of distance. Monocular testing showed a lateral shift in pointing to targets in opposite directions for each eye. This indicates that registered, as opposed to actual, convergence is a factor in near distance perception, and that opposite adaptation occurs within the motor control system for each eye.
The Effects of Hypothermia and Hunger on the Duration of Bar Pressing for Intracranial Self-Stimulation in Rats
Authors: Bloomfield T. M. , Mrosovsky N.
Published: July 2007

Hypothermic rats at rectal temperatures below 30° C showed decreased duration of bar pressing for intracranial self-stimulation in lateral hypothalamic sites. The same effect was found in hungry rats. Both with cooling and hunger, decreased durations were accompanied by decreased thresholds. The threshold changes in hypothermic rats exceeded 12 μA in some cases. The results are relevant to explanations of why animals turn off rewarding brain stimulation. Particular attention is given to the possibility that cooling enhances neural activity in facilitatory connections between positive and aversive systems.
The Effect of Reduced Spatial Cues on the Learning of Successive Visual Reversals
Authors: Winefield A. H.
Published: July 2007

The performance of rats over 12 brightness discrimination reversals was studied under two experimental conditions. Under one condition all visual cues external to the apparatus were eliminated so that only the relative positions of the discriminanda could serve as a visual cue to spatial position. Under the other condition all visual cues to position were eliminated. Under the former condition performance deteriorated with successive reversals but under the latter condition performance improved. Implications of these results for theories of successive reversal improvement were discussed and two possible explanations were suggested.
An Investigation of the Relationships between Problem Solving Strategies, Representation and Memory
Authors: Wood David , Shotter John , Godden Duncan
Published: July 2007

There has been considerable debate in recent years about the status of “imagery” in problem solving. The present experiment attempts to show that while subjects may employ representational strategies when they first encounter a class of problems, they abandon such strategies as they gain experience with the problems. It does this by asking subjects to answer unexpected questions which are based upon the information which they have just used to solve a problem. The hypothesis, which is supported by the results, is that increasing experience with problems will be paralleled by a decreasing ability to answer unexpected questions. The experiment also shows that such effects are not attributable to a build-up in proactive interference.
The Relative Lability of Mobile and Stationary Components in a Visual-Motor Adaptation Task
Authors: Howard Ian P. , Anstis Tania , Lucia Howard C.
Published: July 2007

The results of previous studies of intermanual transfer of prism adaptation may have been biased because the arm was mobile during training, rather than for instance the head. It was hypothesized that adaptation will be more associated with a joint when it is mobile rather than stationary. Intermanual transfer when arm was mobile and head stationary was compared with that when head was mobile and arm stationary. Also measured was the adaptation persisting when the mobile part in training was stationary in testing. The results showed, against the original hypothesis, that adaptation tends to be associated with a stationary joint. This fits in with evidence that there is greater position uncertainty in a stationary joint and that this is associated with adaptability.
A Word Superiority Effect without Orthographic Assistance
Authors: Henderson Leslie
Published: July 2007

In a binary classification task meaningful but unpronounceable letter strings were compared faster than meaningless strings. This effect obtained when only one member of a pair was meaingful and it increased with number of letters. These results suggest that analysis proceeds in parallel at various levels of the processing hierarchy with interaction between semantic and graphemic processes.
Effects of Retinal Adaptation on Brightness Estimation in Humans: Temporal Considerations
Authors: Papaioannou Late J.
Published: July 2007

Human subjects were asked to identify one of seven possible luminance levels under Ganzfeld conditions. The luminance range investigated was 0.5–500.0 ft 1m. Earlier findings on the subjective effects of a Ganzfeld on humans were verified. Subjects performed significantly better under non-adapted than under adapted conditions. Under both conditions subjects tended to perform better after pupillary diameter had been fixed. Errors never exceeded 1 log10 unit in magnitude.
Strategies of Simultaneous Discrimination Learning in the Pigeon
Authors: Hall Geoffrey
Published: July 2007

In Experiment I pigeons were trained on a simultaneous discrimination between red and orange. After they had overcome their position habits and mastered the problem they were presented on occasional test trials with two red or with two orange stimuli. On those test trials when both stimuli were positives the birds tended to peck always to one key; this key was the preferred key during the position habit phase of acquisition. On trials with two negative stimuli the birds chose the other key. These results suggest that the pigeons use the presence of the S− on their preferred side as a cue for pecking to the other side. Experiment II investigated the role of the S+. Transfer tests involving the introduction of a neutral stimulus suggested that pigeons vary in the extent to which they rely upon the S+. Some birds showed no preference for the S+ over the neutral stimulus. However, when required to learn a discrimination between the old S+ and the neutral stimulus, birds given the old S+ as the positive learned more rapidly than those given the neutral stimulus as the positive.
Visual Discrimination Learning and Transfer in Rats with Hippocampal Lesions
Authors: Stevens Robin , Cowey Alan
Published: July 2007

Two experiments were performed on rats with hippocampal brain damage and on a control group with neocortical lesions. In the first experiment the hippocampal group learned a difficult visual discrimination as promptly as the controls, and neither group was subsequently impaired by adding relevant or irrelevant background cues to the original stimuli. In the second experiment the animals learned a simultaneous visual discrimination in which the stimuli differed in both brightness and orientation. The hippocampal group was impaired relative to the controls on acquisition, and showed poorer transfer to stimuli differing only in brightness or orientation. The results are incompatible with the hypothesis which attempts to explain the effects of hippocampal damage by a widespread reduction in sensory gating, but they are consistent with a more restricted version of the same hypothesis.
The Non-Occurrence of a Stimulus as a Signal
Authors: Lea S. E. G.
Published: July 2007

Two groups of rats were rewarded for pressing a panel following a varying number of bar presses; a signal following the bar press indicated whether or not a panel press would be rewarded if made before the next bar press. For one group the signal indicating reward was a flash of light, for the other it was the non-occurrence of the flash (in the latter case the flash thus signalled non-reward). The first group learned to withold panel presses except when reward was signalled, but the second group did not. This result is related to the “feature positive effect” of Jenkins and Sainsbury (1970), in which pigeons failed to withold pecks at a negative stimulus display when it was the same as the positive display except for the addition of a distinctive feature.
The Time Course of Preparation after a First Peak: Some Constraints of Reacting Mechanisms
Authors: Alegria Jesus
Published: July 2007

The aim of this work was to study the time-course of preparation when a two choice stimulus arrives, in a predictable (Experiment I) or unpredictable (Experiment II) manner, after the moment at which it was expected. Subjects watched the screen of an oscilloscope on which a spot moved horizontaly. Vertical lines marked (a) the starting point of the spot's course, t0, and (b) the points in time, t1 … t1, at which the stimulus could arrive. In Experiment I five intervals between t1 and t1, ranging from 150 to 900 ms were used in different blocks of trials. In Experiment II three t1-t1 intervals, ranging from 100 to 400 ms mixed in a random way were used. In both cases subjects were asked to react as fast as possible when the stimulus was presented at moment t1. The time course of preparation was studied when the stimulus arrived at moment(s) t1. The results show that reaction time reaches a maximum 250 ms after t1, irrespectively the predictability of the t1-t1 interval. It is also shown that an interval of about 1 s was necessary to obtain reaction times as rapid as those observed at moment t1. The results are discussed in terms of the evolution of an hypothetical “state of preparation” after a maximum which remains unused.
Effects of Proactive Interference and Rehearsal on the Primary and Secondary Components of Short-Term Retention
Authors: Turvey M. T. , Weeks Robert A.
Published: July 2007

Under the conditions of the distractor paradigm, short-term retention declines to a minimum in a very brief period. The rapid forgetting can be said to reflect the declining contribution of the short-term store or primary memory and the asymptote can be taken as a measure of the contribution of the long-term store or secondary memory. It was shown that manipulating proactive effects by varying the recency of prior material affected only the primary memory component of the short-term retention function. On the other hand manipulating the difficulty of the subsidiary task performed during the retention period with proactive effects held constant affected both the primary and the secondary components. The results were discussed with respect to the relation between the two memory components and the idea that proactive effects are limited to long-term store.
Global Stereopsis in Rhesus Monkeys
Authors: Cowey A. , Parkinson A. M. , Warnick L.
Published: July 2007

In three separate experiments an attempt was made to demonstrate global stereopsis in two rhesus monkeys by using random dot stereograms projected and viewed through polarizing filters. Although both animals learned a number of discriminations, control tests showed that both were perceiving non-depth cues such as monocular identification of minute pattern differences or brightness differences caused by reflections of polarized light. In a final experiment red/green anaglyph forms of the stereograms were viewed through red/green filters. Both monkeys, together with a third experimentally naive animal, showed incontrovertible evidence of prompt discrimination based on stereopsis. This paper makes a number of recommendations about the use of random dot stereograms to demonstrate global stereopsis in animals.
The Effects of Intensity and Interval Rhythms on the Perception of Auditory and Visual Temporal Patterns
Authors: Handel Stephen , Yoder Delmar
Published: July 2007

Repeating temporal patterns were presented in the auditory and visual modalities so that: (a) all elements were of equal intensity and were equally spaced in time (uniform presentation); (b) the intensity of one element was increased (accent presentation); or (c) the interval between two elements was increased (pause presentation). Intensity and interval patterning serve to segment the element sequence into repeating patterns.

For uniform presentation, pattern organization was by pattern structure, with auditory identification being faster. For pause presentation, organization was by the pauses; both auditory and visual identification were twice as fast as for uniform presentation. For auditory accent presentation, organization was by pattern structure and identification was slower than for uniform presentation. In contrast, the organization of visual accent presentation was by accents and identification was faster than for uniform presentation. These results suggest that complex stimuli, in which elements are patterned along more than one sensory dimension, are perceptually unique and therefore their identification rests on the nature of each modality.
Location and Distance Estimates by Blind and Sighted Children
Authors: Hermelin B. , O'Connor N.
Published: July 2007

Blindfold normal, blindfold autistic and congenitally blind children made reproduction location and distance estimates of an arm movement. For each task they first experienced a standard vertical movement of a predetermined extent. In the test tasks which followed, they either reproduced the movement exactly, reproduced the end point although commencing from a different starting position, or reproduced the same distance from a different starting point. Sighted normal children and blind children performed very similarly on both the reproduction and the location task. However on distance reproduction, the blind children underestimated the longer distances more markedly than did the normals. Autistic children resembled the blind in their attempts to reproduce the longer distances. In addition they had a tendency to overshoot over short distances in all tasks.

The results are discussed in terms of the role of a visual reference system for different aspects of motor movements.
Tactile Short-Term Memory in Relation to the Two-Point Threshold
Authors: Murray D. J. , Ward Roger , Hockley W. E.
Published: July 2007

The purpose of the present work was to discover whether there was a relationship between the sensitivity of a body site as measured by the two-point threshold and the degree or rate of forgetting of a location stimulated at that body site. In Experiment I, it was found that the higher the two-point threshold, the greater the distance between two successive points of stimulation erroneonously thought to be identical (12 body sites). In Experiment II, it was found that forgetting over time was greater when the retention interval was filled with movement or other tactile stimulation than when the retention interval was unfilled (six body sites). It was concluded that highly sensitive areas also show the least degree of forgetting as compared with less sensitive sites, but this statement should be qualified in various ways.
Temporal Aspects of Selective Masking
Authors: Lowe Douglas G.
Published: July 2007

In two experiments, rows of random letter sequences were presented for 100 ms and were patterned masked at varying delays after display offset. In Experiment I recall was probed by visual partial report cues, while auditory probes were employed in Experiment II. Compared to no-masking control conditions, the masking stimulus had a selective effect at the different positions of the rows. The masking stimulus produced the largest decrements in recall of letters from the centre positions of the displays but had a minimal effect on performance at either end of the rows. Furthermore, it was demonstrated that improvements in recall were limited to the centre positions of the rows at increased delays of mask. Subsidiary analyses revealed that processing of the end letters of the displays terminates shortly after display offset while processing of the centre letters continues for at least 500 ms. The results are consistent with the notion that processing of multi-letter arrays commences at the ends of the rows and that the selective masking effect reflects the order of processing of the contents of iconic memory. However, these results were evident only in Experiment II which employed auditory partial report cues. When the partial report cues were visual, there were no effects of masking and minimal increases in performance at increased delays of mask. The discrepant results of the two experiments are discussed in terms of process interruption caused by obligatory attention to the partial report cues.
“Next-to-nothings” and Nothingness: A Study of Attention, Attenuation and the Stimulus Prefix Effect
Authors: Routh D. A. , Walker D. J.
Published: July 2007

The stimulus prefix effect, in which a non-recallable item placed at the beginning of a to-be-remembered string of items creates interference, was studied using a 1-s simultaneous visual method of presentation. Two variants on the standard prefix condition were used; in one, the prefix, o, was presented in a different colour from the memory string of seven digits and, in the other, the prefix consisted of three identical zeroes. The three prefix conditions were compared with two control conditions in which either seven or eight digits were presented. No evidence of prefix effects was found in the recall data over serial positions 1–4, for which retrieval was highly efficient, and it was concluded that the action of response set may exclude the prefix from a response buffer (c.f. Morton, 1970). There was also no evidence that the specialized prefixes led to an attenuation of the interference found in the remaining positions. The latter finding is considered to be contrary to a unit-formation hypothesis (Kahneman, 1973) but is consistent with a mode of operation of the logogen model (Morton, 1970).
Burst Cues, Transition Cues, and Hemispheric Specialization with Real Speech Sounds
Authors: Allard F. , Scott Brian L.
Published: July 2007

Subjects listening to dichotically presented real speech stop and fricative consonants, with and without transitions, showed larger laterality effects in the transition-less condition. In a second study, laterality effects for burst cues and transition cues were compared; using the stop consonants /b/ and /d/. Again, burst cues produced a larger laterality effect. These results are not compatible with a lateralized speech “decoder”, and are interpreted as favoring a Semmes (1968) model of hemispheric differences, differential processing.
Binocular Stimulation and the Fragmentation of After-Images
Authors: Forde James , Mackinnon G. E.
Published: July 2007

Two studies were undertaken to investigate the effects of binocular stimulation on the fragmentation of after-images. Binocular after-images were produced by stimulating simultaneously, with intense flashes of light, homologous areas of the two retinas. The after-images from such stimulation were found to be more stable than those produced by monocular stimulation. A third study examined the fragmentation of after-images observed by individuals who either lacked binocular vision and stereoscopic depth perception or who had a history of difficulty with these aspects of vision. Such individuals reported far lass fragmentation than normal observers. The results are discussed in the light of research on the responses to binocular inputs of single cells in monkey occipital cortex.
Reduced Efficiency and Capacity Limitations in Multidimension Signal Recognition
Authors: Long John
Published: July 2007

The first part of Experiment I showed that subjects recognized difficult frequency and intensity signals significantly less well when these were presented together than when they were presented alone. It was estimated that contingent variability resulting from other dimension signal and response context occurring on the same trial accounted for a third of the reduction, and capacity limitations for the remainder. Efficiency on the two dimensions presented together was found to be related and two data subsets were identified for which no efficiency reduction occurred. In the second part of Experiment I subjects recognized correlated frequency and intensity signals and showed a significant improvement in performance over either dimension performed alone. The gain in efficiency was well predicted by the “integration” model of Green and Swets (1966) from one- but not from two-dimension performance. The result suggested that the reduction in efficiency associated with capacity limitations was a function not of the number of signals but of the number of difficult decisions. Experiment II replicated the first part of Experiment I with easy signals. Efficiency was the same whether the signals were presented together or alone. The result indicated that the reduction in efficiency with difficult signals was not due to response interference or to failures of post-recognition retention. The implications of the results for models of attentional capacity are discussed.
The Effects of Isolation Rearing on Behavioural Inhibition in the Rat
Authors: Morgan M. J. , Einon D. F. , Nicholas D.
Published: July 2007

The possibility that isolation-rearing in the rat affects the development of inhibitory mechanisms was studied in a series of experiments. It was found that socially-isolated rats were (1) slower to learn both a lever-panel alternation, and a two-lever alternation schedule of reinforcement, (2) more persistent than controls in pressing a lever for food when a supply of identical “free food” was introduced into the operant chamber, but (3) similar to control rats in their response to preloading with food, a procedure which inhibited lever pressing to the same extent in the two groups. Finally, it was shown in a separate experiment that the effects of increased food deprivation on lever pressing in the presence of free food were qualitatively different from the effects of social isolation, and therefore the social/isolate difference cannot be interpreted as motivational. The possible contributions of neophobia to the difference are discussed. It is concluded that isolates may well suffer from a disinhibitory defect, but that there are probably other effects of isolation in addition.
The Perceptual Fragmentation of Unstabilized Images
Authors: Walker Peter
Published: July 2007

The readiness with which different stimuli disappear when viewed as stabilized images is compared with their behaviour in binocular and monocular rivalry. The results normally associated with stabilized images are reproduced in these non-stabilized conditions. In the context of monocular rivalry, where a red figure that is superimposed on a green field readily disappears, two additional observations are made. First, the nature of the field boundary within which images are viewed, influences their readiness to disappear. Angular figures disappear more or less readily than curved figures, depending whether the field boundary is circular or square. Second, the movement masking phenomenon, previously observed in binocular rivalry and stabilized imagery, is reproduced in monocular rivalry.
Behavioural Contrast Does Not Occur with Continuous Reinforcement in the Positive Component
Authors: Scull John W. , Macphail Euan M.
Published: July 2007

An experiment reported by Jenkins (1961) obtained positive behavioural contrast in a discrimination with continuous reinforcement of the positive stimulus. A large body of research, however, has failed to obtain positive contrast with this type of schedule. Jenkins's experiment was repeated with an added control group matched to the discrimination group in number of nonreinforced components. No positive contrast was obtained, and it was concluded that Jenkins's result could not be interpreted as positive contrast. The implications of this result for some theoretical accounts of positive contrast were discussed.
On the Disruption of Visual Memory: Interference Produced by Visual Report Cues
Authors: Merikle Philip
Published: July 2007

Report of single letters from centrally-fixated, seven-letter, target rows was probed by either auditory or visual cues. The target rows were presented for 100 ms, and the report cues were single digits which indicated the spatial location of a letter. In three separate experiments, report was always better with the auditory cues. The advantage for the auditory cues was maintained both when target rows were masked by a patterned stimulus and when the auditory cues were presented 500 ms later than comparable visual cues. The results indicate that visual cues produce modality-specific interference which operates at a level of processing beyond iconic representation.
Handedness and Cognitive Bias
Authors: Heim A. W. , Watts K. P.
Published: July 2007

2165 Subjects, ranging from nine-year-old schoolchildren to adult students, took Test AH 2/3 which yields subscores on Verbal, Numerical and Perceptual reasoning. The left-handers are compared with the right-handers, differences being found with respect to cognitive bias, sex, age and nationality.
Reversible Effects of Ambient Housing Stimulation upon Stimulation-Seeking in Rats
Authors: Inglis I. R. , Freeman N. H.
Published: July 2007

Two types of housing condition, low and high ambient stimulation, were alternated. The effects of this treatment upon rats' subsequent stimulation-seeking behaviour were assessed in a multiple-choice head-input apparatus. The aim of the experiment was to determine whether adult animals would adapt and re-adapt to varying periods of upward and downward shifts in the levels of housing stimulation. A given housing-stimulation had a lawfully cumulative effect which could be completely reversed when housing conditions altered. The most sensitive measures were latency and response rate in the first 5 min of the test. One measure, relative preference for illuminated stimuli over a dark stimulus, gave an indication of the time-lag involved in adaptation to a new housing condition.
Directed Movements and the Body-Proportion Effect in Preschool Children's Human Figure Drawing
Authors: Freeman N. H. , Hargreaves S.
Published: July 2007

Drawing a human figure involves mastery over complex planning problems. The variant forms which young children produce may be an index of these. The most common variant is the “tadpole figure” with arms seemingly on the head. It is known that children who spontaneously draw this variant will attach arms correctly to the trunk of an incomplete pre-drawn figure if the head is small, but will attach them to the head if that exceeds the trunk in size. The present study shows that this body-proportion effect cannot be reliably modified by directing the pen to the head or trunk for the purpose of drawing body-parts other than arms; and that the arms are much more subject to the effect than the legs, nose, navel or ears. Experimental analysis of drawing based on completion-tasks can in principle help to bring out, and put under stimulus-control, performance characteristics which cannot reliably be inferred from post-hoc inspection of spontaneous finished products.
The Representation of Spatial Information in Memory
Authors: Wilton R. N. , File Portia E.
Published: July 2007

Following memorisation of the spatial arrangement of an array of circles, subjects were asked to recall the circles in a type of free-recall task designed to determine the structure of the memorised information. Their performance showed that the circles tended to be recalled in an order that corresponded with a top-to-bottom ordering of circles on the array. In a second experiment the input order of the circles was varied by presenting them successively. The results indicated that input order influenced recall order. The implications for hypotheses about the structure and manipulation of stored spatial information were discussed.
Reading without Phonology: Evidence from Aphasia
Authors: Saffran Eleanor M. , Marin Oscar S. M.
Published: July 2007

This study of an aphasic dyslexic supports the view that there are separate visual and phonological pathways in reading. The patient retained a reading vocabulary of at least 16 500 words although she was unable to perform operations that critically depend on grapheme-to-phoneme conversion; these included reading nonsense words, recognizing rhymes and homophones, and accessing lexical entries from homophonic spellings such as “kote”. Typographical variation, such as mixed case presentation, did not interfere with her reading performance, which suggests that it is mediated by letter identification rather than by a wholistic method of word recognition. The total performance pattern strongly suggests that this patient identifies words by matching particular letter-strings with their corresponding meanings.
Conditioned Suppression of DRL Responding: Effect of UCS Intensity, Schedule Parameter, and Schedule Context
Authors: Randich Alan , Jacobs W. J. , Lolordo Vincent M. , Sutterer James R.
Published: July 2007

In Experiment I, groups of rats were trained to press a lever for food reinforcement on differential reinforcement of low rate (DRL) schedules which differed in parameter value. A stimulus which terminated with either a 0.5-mA or 2.0-mA electric shock was then superimposed upon each DRL baseline. In general, the magnitude of conditioned suppression was an inverse function of DRL schedule parameter and a direct function of shock intensity. Experiment II demonstrated that the rate of responding maintained by the DRL component of a multiple DRL-extinction schedule decreased during a stimulus preceding a 0.5-mA shock, whereas the rate of responding maintained by the DRL component of a multiple DRL-variable interval schedule showed little change or increased slightly during a stimulus preceding a 0.5-mA shock.
Early Isolation Produces Enduring Hyperactivity in the RAT, But no Effect upon Spontaneous Alternation
Authors: Einon Dorothy F. , Morgan M. J.
Published: July 2007

Rearing rats in isolation between 23 and 45 days caused a lasting increase in photocell-cage activity, even if the animals were subsequently rehoused in social groups until 125 days of age. In contrast to its effects upon activity, isolation had no effect upon spontaneous alternation in a Y-maze. This dissociation argues for caution in relating hyperactivity and reduced alternation to a unitary deficit in an inhibitory system.
Discrimination without Awareness?
Authors: Forster Peter M. , Govier Ernest
Published: July 2007

The fate of the unattended message in dichotic listening experiments is a much disputed issue. Moray (1969) proposes that there is no processing of the unattended message, whereas Norman (1969) has suggested that it is analyzed to the level of meaning. In order to test these alternative hypotheses an experiment was performed in which galvanic skin responses (GSR) were conditioned to a word (CS) by pairing it with shock. The word was then included in passages of prose presented to subjects as the attended and unattended messages in a dichotic listening task. GSR's were obtained to the occurrence of CS in the unattended message and also to words acoustically similar to CS and to synonyms of CS. The probability of obtaining a GSR to the occurrence of an accoustically similar word was increased by placing that word in a context appropriate to CS. These results suggest that the unattended message can be processed to a level at which semantic information is extracted without the subject's reported awareness.
Visual Search of Common Scenes
Authors: Meyers Lawrence S. , Rhoades Robert W.
Published: July 2007

A visual search reaction time task was used to examine the relationships among encoding, comparison, and search processes. Targets, either pictures of objects or their names, were briefly presented and followed, at stimulus onset asynchronies (SOAs) ranging from 200 to 2000 ms, by pictorial scenes having a 50% probability of containing the target. Generally, subjects responded more rapidly with picture than word targets, this difference diminishing at longer SOAs. Searches appeared to be restricted to certain portions of the scene depending on the congruency between the target and the scene. The sequence of decisions in the search task was discussed.
Some Errors of Perceptual Analysis in Visual Search can be Detected and Corrected
Authors: Rabbitt Patrick , Cumming Geoffrey , Vyas Subhash
Published: July 2007

This experiment tried to discover whether people can correct errors which occur because they incorrectly analyse a display to which they have to respond—whether, in fact, they can correct “perceptual” as well as “motor” errors. In a serial, self-paced visual search task, subjects made one response to indicate that a display of five or nine letters contained either of a pair of target letters, and another response when no target was present. Omission errors were much more common than False Identification Errors, but more of them were corrected. Omission errors were detected and corrected faster than False Identification Errors. Typically omission errors were slow responses while False Identification Errors were fast responses. It is possible to deduce that at least some errors resulting from incorrect analysis of a display can be detected and corrected, probably because of an extension of perceptual analysis during, or immediately after, the time when a response to the display is made.
Timing in the Motor Programming of Typing
Authors: Shaffer L. H.
Published: July 2007

In developing a theory of motor programming of skilled performance it has been suggested that an abstract, structural representation in the program specifies both a sequence of responses and expressive features of the sequence, such as timing, stress and intonation, which are mapped separately into the response output. In the case of typing, which does not require expressive features, it has previously been assumed that response timing is governed more simply by a timekeeper providing a stochastically regular beat. Two sets of specially constructed texts were given to a fast typist and the results support the idea that skilled typing is paced by a regular beat. They also show that there were systematic rhythmic departures from the beat, which arose from contingencies of keyboard movement but were not the simple consequences of these; rather they may be regarded as structured anticipations of the contingencies, and as such are analogous to the expressive features of speech and playing music.