Positional character frequency and word spacing facilitate the acquisition of novel words during Chinese children's reading

Children's eye movements were recorded to examine the role of word spacing and positional character frequency on the process of Chinese lexical acquisition during reading. Three types of two-character novel pseudowords were constructed: words containing characters in positions in which they frequently occurred (congruent), words containing characters in positions they do not frequently occur in (incongruent) and words containing characters that do not have a strong position bias (balanced). There were two phases within the experiment, a learning phase and a test phase. There were also two learning groups: half the children read sentences in a word-spaced format and the other half read the sentences in an unspaced format during the learning phase. All the participants read normal, unspaced text at test. A benefit of word spacing was observed in the learning phase, but not at test. Also, facilitatory effects of positional character congruency were found both in the learning and test phase; however, this benefit was greatly reduced at test. Furthermore, we did not find any interaction between word spacing and positional character frequencies, indicating that these two types of cues affect lexical acquisition independently. With respect to theoretical accounts of lexical acquisition, we argue that word spacing might facilitate the very earliest stages of word learning by clearly demarking word boundary locations. In contrast, we argue that characters' positional frequencies might affect relatively later stages of word learning.     

Do you know where your fingers have been? Explicit knowledge of the spatial layout of the keyboard in skilled typists

Two experiments evaluated skilled typists’ ability to report knowledge about the layout of keys on a standard keyboard. In Experiment 1, subjects judged the relative direction of letters on the computer keyboard. One group of subjects was asked to imagine the keyboard, one group was allowed to look at the keyboard, and one group was asked to type the letter pair before judging relative direction. The imagine group had larger angular error and longer response time than both the look and touch groups. In Experiment 2, subjects placed one key relative to another. Again, the imagine group had larger angular error, larger distance error, and longer response time than the other groups. The two experiments suggest that skilled typists have poor explicit knowledge of key locations. The results are interpreted in terms of a model with two hierarchical parts in the system controlling typewriting.     

Redistributing control between the elements of a compound stimulus

Twenty-eight pigeons were given discrimination training. Four groups were run in which for 0, 2, 4 and 9 sessions of training colour was an irrelevant cue and tone was relevant. Generalization tests were given in extinction; the training colour (C₁) and another colour (C₂) were presented with tone (T) and noise (N). Responding to these four stimulus combinations, TC₁, TC₂, NC₁ and NC₂, allowed the assessment of control by colour and tone. A reduction of control by colour and an increase in control by tone were found to be positively related to the amount of training with colour irrelevant. Tests showed a strong inverse relationship between control by colour and tone.     

Maintenance and generalization of a semantic rehearsal strategy in educable mentally retarded children

Two groups of 11- to 12-year-old educable mentally retarded children, equated on the basis of a free recall pretest, were given a series of lists for free recall. Approximately half the subjects were trained in the use of a strategy designed to induce deeper level semantic encoding and the discovery of categorical relationships and half constituted a “no-training” control group with standard free recall instructions. The subjects received either related or unrelated lists during the training phase and related or unrelated lists during two post-tests, immediately following and 1 week after training. There was evidence not only that the semantic strategy was maintained over the 1-week delay, but that it also generalized to word lists unlike those used during training. The degree of generalization was greater for those subjects receiving related lists during training.     

Memory processing of spatial order as transmitted by auditory information in the absence of visual cues

Two experiments were conducted concerning spatial order recall when spatial information is transmitted by auditory stimuli. Temporal order either was congruent with spatial order or was independent of spatial order. In Experiment 1, the comparisons were among normally or partially sighted subjects allowed to look, normally sighted subjects who were blindfolded, and blind children. The main findings were a superiority of the sighted subjects allowed to look (that is, to support auditory information with visual cues) and a smaller advantage for the sighted-but-blindfolded subjects, relative to the blind group. In Experiment 2, normally sighted adults (either seeing or blindfolded) and blind adults were tested. Surprisingly, the blind were not worse than the sighted in this study. Subsequent interviews and detailed analysis of errors suggested that the blind coded spatial information kinesthetically. These indirect analyses also suggested that whereas spatial order was coded temporally in the sighted, it was controlled by both temporal and spatial factors in the blind and blindfolded subjects.     

Discriminative stimulus effects of diazepam and buspirone in normal volunteers.

A within-subject design was used to characterize the effects of dose manipulations on discriminative and self-reported effects of oral diazepam and buspirone. Subjects were trained to discriminate diazepam (10 mg) versus placebo (n = 10), or buspirone (10 or 15 mg) versus placebo (n = 9). The compounds were identified to subjects by letter code before discrimination training began. In later sessions, correct identifications at 2 hr after the oral administration of drug earned money. All subjects showed accurate discrimination performance during the test-of-acquisition phase. In a low-dose generalization phase, diazepam and buspirone produced dose-related increases in drug identifications across a four-fold range of doses. In a subsequent low-dose training phase, in which subjects were trained to discriminate progressively lower drug doses, the median lowest discriminable dose of diazepam and buspirone was 2.5 and 7.5 mg, respectively. Dose-response functions for drug identifications were shifted leftward in the low-dose training phase relative to the low-dose generalization phase, suggesting that reinforcement of progressively lower doses enhances drug discriminability. The self-reported effects of diazepam and buspirone were similar (e.g., both drugs increased ratings of drug strength and clumsy/uncoordinated) and different (e.g., diazepam but not buspirone increased ratings of drowsy/sleepy; buspirone but not diazepam increased ratings of tense/nervous). This study demonstrates discriminative and self-reported effects of diazepam and buspirone at doses lower than previously shown to be behaviorally active, and suggests that at commonly used clinical doses, diazepam is relatively more discriminable than buspirone.     

Identification of disoriented objects: effects of context of prior presentation

Half of the subjects in the training phase of Experiment 1 named objects shown in a number of orientations, whereas the other half named objects shown upright only. All subjects named objects seen in a number of different orientations in the transfer phase. Half of the objects in the transfer phase were the ones they had seen in the training phase (old objects), whereas the other half were objects they had not seen before (new objects). Mean naming time in the transfer phase increased more as the objects were rotated further from the upright for new objects than for old objects when the old objects had been seen in a variety of orientations. In contrast, a substantial and equivalent orientation effect on identification time was obtained for old and new objects when the old objects had been seen upright only. These results suggest that the extraction and use of orientation-invariant attributes to identify objects is not a "default" identification strategy employed by the human visual system. In Experiment 2, half of the objects named in the training phase were shown upright only, whereas the other half were shown in a number of orientations. Both types of objects (upright vs. rotated) were presented in a mixed fashion from trial to trial. The results revealed that prior naming of the objects in this context resulted in equivalent reductions in the magnitude of the orientation effect on identification time for both sets of objects (upright and rotated). Together, the results of these two experiments suggest that markedly different representations of objects are encoded, depending on the context in which objects are seen. Implications for models of pattern recognition are discussed.     

Touch screen assays of behavioural flexibility and error characteristics in Eastern grey squirrels (<Emphasis Type="Italic">Sciurus carolinensis</Emphasis>)

Behavioural flexibility allows animals to adjust their behaviours according to changing environmental demands. Such flexibility is frequently assessed by the discrimination–reversal learning task. We examined grey squirrels’ behavioural flexibility, using a simultaneous colour discrimination–reversal learning task on a touch screen. Squirrels were trained to select their non-preferred colour in the discrimination phase, and their preferred colour was rewarded in a subsequent reversal phase. We used error rates to divide learning in each phase into three stages (perseveration, chance level and ‘learned’) and examined response inhibition and head-switching during each stage. We found consistent behavioural patterns were associated with each learning stage: in the perseveration stage, at the beginning of each training phase, squirrels showed comparable response latencies to correct and incorrect stimuli, along with a low level of head-switching. They quickly overcame perseveration, typically in one to three training blocks. In the chance-level stage, response latencies to both stimuli were low, but during initial discrimination squirrels showed more head-switches than in the previous stage. This suggests that squirrels were learning the current reward contingency by responding rapidly to a stimulus, but with increased attention to both stimuli. In the learned stage, response latencies to the correct stimulus and the number of head-switches were at their highest, whereas incorrect response latencies were at their lowest, and differed significantly from correct response latencies. These results suggest increased response inhibition and attention allowed the squirrels to minimise errors. They also suggest that errors in the ‘learned’ stage were related to impulsive emission of the pre-potent or previously learned responses.     

Role of optical flow field asymmetry in the perception of heading during linear motion

During linear translation through a stationary environment, the pattern of optical flow generated on each retina is symmetrical when the head is aligned with the heading, but during lateral gaze the optical flow is asymmetric. We assessed whether human subjects could use the magnitude of this asymmetry to determine the direction of heading during passive translation through a 3-D environment. When allowed to move their heads in order to look in the direction of self-motion, subjects indicated their heading precisely and accurately. When the head was locked in alignment with the misaligned body, and gaze adjustments were not allowed, responses were quite precise, but showed a large bias which increased with increasing heading angle.     

The role of stimulus comparison in perceptual learning: An investigation with the domestic chick

In two experiments an imprinting procedure was used to familiarize chicks with two stimuli, A and B, that subsequently served as the discriminanda in a simultaneous discrimination. On the first day of each experiment, subjects either received presentations of A and B that were intermixed within a session (mixed exposure) or presentations of A in one session and of B in another (separate exposure). For half of the subjects in each of the exposure conditions, A and B differed in both colour and form; for the remainder A and B differed in form alone. On the second day of the experiments, the chicks were placed into a cool test apparatus and given training in which approaching A was rewarded by the delivery of a stream of warm air, but approaching B was not. Acquisition of this discrimination was more rapid when A and B differed in two respects than when they differed in form alone. When A and B differed in both colour and form, the heat-reinforced discrimination was acquired more rapidly after separate exposure than after mixed exposure; but when A and B differed in form alone, discrimination learning was more rapid following mixed exposure than separate exposure. The latter finding, that the opportunity to compare stimuli differing in only one dimension facilitates subsequent discrimination learning, is consistent with earlier suggestions (Gibson, 1969) regarding the conditions that promote perceptual learning.     

Training strategic study time apportionment in educable retarded children

Two groups of educable retarded children differing in functioning level served as subjects. One group, the High group, consisted of 31 children drawn from the upper two classes of a five-class stream. The Low group consisted of 39 children drawn from the lowest two classes. During pretesting, on each trial but the first of a multitrial free recall procedure, subjects were allowed to select half of the to-be-remembered items to see if they would strategically select missed items for extra study. Following pretesting, subjects were divided for training into three groups for which the experimenter selected items for study: in the Standard group, missed items; in the Creeping group, recalled items plus one missed item; and in the Random group, half missed and half recalled items. Children in the High group improved in the Standard condition, and those in the Low group benefited from Creeping training. There was no evidence of maintenance of training in the Low group, but children in the High group given training in the standard strategy selected missed items for recall on the posttests. The results are discussed in terms of the stability of trained strategies in retardates, and the question of what constitutes an optimal strategy is considered.     

The generality of learned helplessness in the rat

Two experiments were simultaneously conducted in which two different groups of 40 rats each were exposed to one of two different stressors. In both experiments half the subjects were pretreated with shock, half with underwater exposure. For each pretreatment stressor, half the subjects were allowed to escape, the other half were not. The experiments differed in the test task used. Approximately 24 hr after pretreatment, one-half the subjects from each pretreatment group received 20 water-escape trials in an underwater maze, the other half received 20 shock-escape trials in a two-way shuttle box. The subjects in each of the inescapable pretreatment conditions were slower to escape in the subsequent shock-escape and water-escape tasks when compared with subjects in the corresponding escapable pretreatment condition. The “learned helplessness” effect appeared to be no smaller when aversive stimuli were changed between pretreatment and test than when they remained the same.     

An evaluation of touch on a large request: a field setting

The effect of touch on compliance to a request has traditionally been tested with small solicitation (answer to a small questionnaire, give a dime to a confederate ....). In our experiment a larger request was evaluated. Passersby, 53 men and 67 women, were asked by two confederates to look after a large and very excited dog for 10 minutes because each wanted to go into a pharmacy where animals were prohibited. In half of the cases, subjects were touched during the request. Analysis showed that, when touched, 55% of the subjects agreed with the request whereas 35% only in the no-touch control condition agreed. This finding indicates that touch was positively associated with the subjects' compliance (p<.03).     

Efficacy of booster sessions after training in assertiveness

28 subjects participated in a 6-wk. assertion training program. Of these, 22 remained in the study for a 6-mo. follow-up period, during which half received monthly booster sessions and half did not. Assignment to the booster and no-booster groups was random, with the qualification that subjects were equated on trait anxiety before training in assertiveness. Subjects filled out the Gambrill-Richey Assertion Inventory, the Spielberger State-Trait Anxiety Inventory, and the Zung Self-rating Depression Scale before the 6-wk. assertion training, after this program, at a 3-mo. follow-up, and at a 6-mo. follow-up. It was hypothesized that the booster group would exhibit significant superiority on these measures at the 3-mo. and 6-mo. follow-ups. On all measures both groups significantly improved from before to after the training program with good maintenance throughout the follow-ups. There were no differences between the booster and no-booster groups on the measures of assertiveness and anxiety. However, there was a significant interaction for the depression scores when the booster and no-booster groups were compared from posttreatment to 6-mo. follow-up. The depression scores of subjects in the booster group were lower than the depression scores of subjects in the no-booster group at the 6-mo. follow-up. These results were discussed with suggestions for further research.     

Low-dose caffeine discrimination and self-reported mood effects in normal volunteers.

A caffeine versus placebo discrimination procedure was used to determine the lowest caffeine dose that could produce discrimination and self-reported mood effects in normal volunteers. During daily sessions under double-blind conditions, caffeine-abstinent subjects orally ingested a capsule containing 178 mg caffeine or placebo. Before beginning discrimination training, the compounds were identified to subjects by letter codes. Fifteen, 30, and 45 min after capsule ingestion, subjects guessed the capsule's letter code. Correct guesses at 45 min earned money. After each session, subjects received a supplementary capsule containing caffeine or placebo to ensure that, within each phase of the study, subjects received the same daily dose of caffeine equal to the training dose. Five of the 15 subjects acquired the caffeine versus placebo discrimination within the first 20 sessions (greater than or equal to 75% correct); 6 other subjects acquired the discrimination with additional training. Nine subjects who acquired the discrimination were subsequently trained at progressively lower caffeine doses. In general, the lowest dose to produce discrimination (greater than or equal to 75% correct) was also the lowest dose to produce self-reported mood effects: 4 subjects showed discrimination and self-reported mood effects at 100 mg caffeine, 2 at 56 mg, 1 at 32 mg, and 1 at 18 mg. One of these subjects also showed self-reported mood effects at 10 mg. The present study documents discriminative stimulus and self-reported mood effects of caffeine at doses below those previously shown to affect any behavior in normal volunteers.     

The effect of subject-generated and experimentersupplied code words on the phonetic mnemonic system

The hypothesis tested proposed that subjects using the phonetic mnemonic system who were supplied code words by the experimenter would recall more numbers than either subjects generating their own code words or a control group. In Experiment 1,36 undergraduate subjects serving in a 3 × (3) mixed-factorial design confirmed the hypothesis, but the possibility existed that the superiority of the experimenter-supplied group was attributable to the failure of the subject-generated group to devise a complete set of code words. In Experiment 2 a new group of 12 self-generated subjects was tested with a modified procedure designed to maximize number of correct code words. However, the experimenter-supplied group recalled significantly more numbers than this group, too. In Experiment 3 the possibility was tested that the superiority of the experimenter-supplied subjects was an artifact based on insufficient training in the phonetic method of subjects creating code words. Accordingly, all 28 subjects received extended training before recall of a subject-generated group was tested against that of an experimenter-supplied group in a 2 × (2) factorial design. Once again the experimentersupplied group recalled significantly more numbers, confirming the hypothesis. These results represent an exception to the general finding that subject-generated mnemonics are superior to those supplied by the experimenter. The data suggest that the relative efficacy of the two sources interacts with the difficulty of the mnemonic.     

Learning,awareness, and instruction: Subjective contingency awareness does matter in the colour-word contingency learning paradigm

In three experiments, each of a set colour-unrelated distracting words was presented most often in a particular target print colour (e.g., “month” most often in red). In Experiment 1, half of the participants were told the word-colour contingencies in advance (instructed) and half were not (control). The instructed group showed a larger learning effect. This instruction effect was fully explained by increases in subjective awareness with instruction. In Experiment 2, contingency instructions were again given, but no contingencies were actually present. Although many participants claimed to be aware of these (non-existent) contingencies, they did not produce an instructed contingency effect. In Experiment 3, half of the participants were given contingency instructions that did not correspond to the correct contingencies. Participants with these false instructions learned the actual contingencies worse than controls. Collectively, our results suggest that conscious contingency knowledge might play a moderating role in the strength of implicit learning.     

Event-related potentials to schematic faces in social phobia

Social phobia has been associated with an attentional bias for angry faces. This study aimed at further characterising this attentional bias by investigating reaction times, heart rates, and ERPs while social phobics, spider phobics, and controls identified either the colour or the emotional quality of angry, happy, or neutral schematic faces. The emotional expression of angry faces did not interfere with the processing of their colour in social phobics, and heart rate, N170 amplitude and parietal late positive potentials (LPPs) of these subjects were also no different from those of non-phobic subjects. However, social phobics showed generally larger P1 amplitudes than non-phobic controls with spider phobic subjects in between. No general threat advantage for angry faces was found. All groups identified neutral schematic faces faster and showed larger late positive amplitudes to neutral than to emotional faces. Furthermore, in all groups the N170 was modulated by the emotional quality of faces. This effect was most pronounced in the emotion identification task.     

The role of attention in the shift from orientation-dependent to orientation-invariant identification of disoriented objects

In two experiments, the naming of rotated line drawings of natural objects was examined after a training phase in which the objects were either attended or ignored. In the training phase of Experiment 1, subjects were presented with objects in a number of orientations over five repeated blocks of trials. In the center of each object, seven letters (Xs and Ts, colored red or blue) were presented in rapid succession. Half the subjects named aloud the rotated object and ignored the changing letter display (object-attend). The other half ignored the object and counted the number of red Ts, and then used this number to perform a simple multiplication (object-ignore). In the test phase, all subjects named the rotated objects. The results showed that in the first block of trials in the training phase, mean naming time in the object-attend condition increased the further an object was rotated from the upright. This effect of orientation for attended objects was much reduced in the later presentations of the test phase. In contrast, there was no such benefit of prior presentation observed for the naming of objects that had previously been ignored. Instead, a substantial orientation effect was shown for the naming of previously ignored objects, which was similar to the orientation effect observed for attended objects named in the first block. Similar results were found in Experiment 2, in which object-attend subjects in training covertly named the objects and then performed a letter count and multiplication task. In both experiments, performance on the letter count and multiplication task varied with the angle of the ignored object. The results suggest that full attentional resources must be allocated in order for orientation-invariant representations to be formed and used in the identification of rotated objects.