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PubMed2003

Children are cursed: an asymmetric bias in mental-state attribution.

Young children have problems reasoning about false beliefs. We suggest that this is at least partially the result of the same curse of knowledge that has been observed in adults--a tendency to be biased by one's own knowledge when assessing the knowledge of a more naive person. We tested 3- to 5-year-old children in a knowledge-attribution task and found that young children exhibited a curse-of-knowledge bias to a greater extent than older children, a finding that is consistent with their greater difficulty with false-belief tasks. We also found that children's misattributions were asymmetric. They were limited to cases in which the children were more knowledgeable than the other person; misattributions did not occur when the children were more ignorant than the other person. This suggests that their difficulty is better characterized by the curse of knowledge than by more general egocentrism or rationality accounts.

Child Development↗
PubMed2002

Affective modulation of eyeblink startle with reward and threat.

An emotion-modulated acoustic startle paradigm for inducing positive and negative affect was used to address pregoal and postgoal affect. Participants played a computerized lottery task in which they chose digits that could match a subsequently displayed, random set of numbers. In the positive conditions, matches led to monetary rewards. In the negative condition, matches led to an aversive noise blast. In three experiments, we found eyeblink startle magnitude was potentiated just prior to feedback concerning reward outcome, suppressed following the feedback that a monetary reward was won, and potentiated when threatened with an aversive noise. When presented with a 0%, 45%, 90%, or 100% chance of winning, higher probabilities suppressed startle response after feedback whereas the 45% trials did not. These data indicate that postgoal positive affect (winning reward) reliably suppressed the startle response whereas pregoal positive affect did not.

Acoustic Stimulation↗
PubMed2002

Temporal dynamics of lateralized ERP components elicited during endogenous attentional shifts to relevant tactile events.

To investigate the temporal dynamics of lateralized event-related brain potential (ERP) components elicited during covert shifts of spatial attention, ERPs were recorded in a task where central visual symbolic cues instructed participants to direct attention to their left or right hand in order to detect infrequent tactile targets presented to that hand, and to ignore tactile stimuli presented to the other hand, as well as all randomly intermingled peripheral visual stimuli. In different blocks, the stimulus onset asynchrony (SOA) between cue and target was 300 ms, 700 ms, or 1,100 ms. Anterior and posterior ERP modulations sensitive to the direction of an attentional shift were time-locked to the attentional cue, rather than to the anticipated arrival of a task-relevant stimulus. These components thus appear to reflect central attentional control rather than the anticipatory preparation of sensory areas. In addition, attentional modulations of ERPs to task-irrelevant visual stimuli were found, providing further evidence for crossmodal links in spatial attention between touch and vision.

Adult↗
PubMed2004

A dissociation between implicit and explicit verbal memory in left temporal lobe epilepsy.

PURPOSE: Temporal lobe epilepsy patients are well known to present deficits on explicit verbal memory procedures (e.g., recall, recognition). The integrity of implicit memory procedures in these patients is not established. Previous studies in this area used implicit memory measures contaminated by the effects of explicit memory. METHODS: We examined the integrity of verbal implicit and explicit memory in left temporal lobe epilepsy (LTLE) patients and hypothesized that a clear dissociation in performance would be found with a relative preservation of implicit memory. TLE patients (n = 15) and age- and education-matched healthy normal patients (n = 15) were shown a 40-word study list, followed by a test phase requiring completion of word stems based on the study words or new/unseen words. Experimental conditions involved instructions to provide either the old (study) words or novel/nonlist words when completing the stem. Measures of automaticity and recollection provided uncontaminated indices of implicit and explicit memory, respectively. RESULTS: The data showed a significant difference (p < 0.001) between the patients (Recollection, 0.12; SD, 0.18) and controls (0.50, SD, 0.15) on the measure of explicit memory. In contrast, the patients (Automaticity, 0.51; SD, 0.11) and controls (0.45, SD, 0.18) performed similarly on the implicit memory measure, with patient scores clearly at normative levels based on other Process Dissociation Procedure data. CONCLUSIONS: The data demonstrate the integrity of implicit memory in LTLE patients. Finding a dissociation between the two forms of verbal memory in LTLE patients provides evidence that they rely on different neuroanatomic systems.

Adolescent↗
PubMed2004

Spontaneous discounting of availability in frequency judgment tasks.

Discounting is a causal-reasoning phenomenon in which increasing confidence in the likelihood of a particular cause decreases confidence in the likelihood of all other causes. This article provides evidence that individuals apply discounting principles to making causal attributions about internal cognitive states. In particular, the three studies reported show that individuals will fail to use the availability heuristic in frequency estimations when salient causal explanations for availability exist. Experiment 1 shows that fame is used as a cue for discounting in estimates of surname frequency. Experiment 2 demonstrates that individuals discount the availability of their own last name. Experiment 3, which used individuals' initials in a letter-frequency estimation task, demonstrates that simple priming of alternative causal models leads to discounting of availability. Discounting of cognitive states can occur spontaneously, even when alternative causal models are never explicitly provided.

Adult↗
PubMed1992

Out of sight or out of mind? Another look at deception in autism.

The penny-hiding game is a deception game that occurs naturally in parent-child and child-child interaction. It involves minimal linguistic demands, and is lots of fun. Oswald and Ollendick (1989) employed it with subjects with autism and reported an impaired capacity for deception. They also found that this correlated with performance on both a false belief ("theory of mind") test as well as various measures of social behaviour. The experiment reported here set out to replicate Oswald and Ollendick's important results, and then extend them by using a new technique for error analysis. We succeeded in replicating the autism-specific deception impairment as well as the finding that deception capacity correlates highly with performance on a false belief test. In addition, the new analytic technique discriminated the group with autism from controls more clearly than the traditional index of deception. Specifically, subjects with autism, whilst fully capable of enjoying the game as a game of object occlusion (keeping things out of sight), failed to perceive the game as a game of information occlusion (keeping things out of mind), unlike normal children or subjects with a mental handicap of an equivalent or lower mental age. The dissociation in autism between occluding objects vs occluding information is discussed in relation to other research showing that subjects with autism are impaired in understanding the principle that "seeing leads to knowing".

Adolescent↗
PubMed2005

Response reversal and children with psychopathic tendencies: success is a function of salience of contingency change.

BACKGROUND: Previous work has inconsistently reported difficulties with response reversal/extinction in children with psychopathic tendencies. METHOD: We tested the hypothesis that the degree of impairment seen in children with psychopathic tendencies is a function of the salience of contingency change. We investigated the performance of children with psychopathic tendencies on a novel probabilistic response reversal task involving four conditions with gradated reward-punishment contingencies (100-0, 90-10, 80-20 and 70-30; i.e., for the 100-0 contingency, responding to one object is always rewarded while responding to the other is always punished). RESULTS: In line with predictions, the impairment seen in the children with psychopathic tendencies was an inverse function of the salience of the contingency change. CONCLUSIONS: We suggest that this data is consistent with suggestions of subtle orbital frontal cortex impairment in children with psychopathic tendencies.

Adolescent↗
PubMed1989

Late components of auditory event-related potentials to eight equiprobable stimuli in a target detection task.

Fourteen normal subjects undertook a target detection task in which eight different but equiprobable stimuli were presented in an unpredictable sequence (four tone frequencies to either the left or the right ear). One tone/ear combination was designated as a target, to be responded to with a rapid button press. Event-related potentials were recorded from an array of six scalp electrodes. In Condition 1 no responses were required; in Condition 2 a response was required to the highest tone in one designated ear; in Condition 3 a response was required to the second highest tone in the ear opposite to the Condition 2 target. Event-related potentials to the no-task condition (1) included a P3-type late positive component. P3 increased in amplitude to target tones in Conditions 2 and 3, but showed equally large amplitude increases and some decrease in latency to nontarget tones in those conditions. However, a frontal Slow Wave component was elicited more specifically by target stimuli. An attended ear effect was evident in a processing negativity that extended for some hundreds of milliseconds prefrontally, but tended to be comprised of two separate negativities over fronto-central locations.

Adult↗
PubMed1990

P300, probability, and interstimulus interval.

The relationship between target stimulus probability and interstimulus interval on the P300 (P3) component of the event-related potential was assessed in three experiments. In each study an auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1,000 Hz tones. Target stimuli were presented with a probability of either .20 or .80 in different conditions which were combined factorially with different interstimulus intervals. Experiment 1 presented stimuli at 2.0, 2.5, or 3.0 second intervals; Experiment 2 presented stimuli at 2.0, 3.0, or 4.0 second intervals; Experiment 3 presented stimuli at 4.0, 6.0, or 10.0 second intervals. P3 amplitude was larger for the .20 relative to the .80 target probability conditions for the shorter interstimulus intervals but not for the longer intervals. P3 latency was consistently longer for the .20 relative to the .80 target probability conditions, with generally little effect observed for interstimulus interval changes. The results suggest that interstimulus interval affects component amplitude by determining the amount of processing resources available when the P3 is produced.

Adult↗
PubMed1991

The waltzing oddball.

We investigated whether task relevance and probability interact to influence P3 amplitude. High and low tones were presented in random order with equal probability. In the control condition (standard oddball), every high tone had to be counted. In the waltz condition, high tones had to be counted only if they were preceded by two other high tones. It was predicted that the P3s evoked by targets in the waltz condition would be larger than the P3s evoked by the same sequence of targets in the oddball condition. That is, the frequency of occurrence of the targets should have an effect on P3, in addition to effects of the frequency of stimulus occurrence and stimulus task relevance (target/nontarget). This prediction was upheld. However, the largest P3s were evoked by nontargets following two high tones in the waltz condition. These P3s had a more anterior topographic maximum than usual. We contend that these anterior P3s reflect the interruption of an ongoing task and cannot be easily fit into the framework of the two concepts of task relevance and probability.

Adult↗
PubMed1992

Taking attention to task: P300, task response probability, and within-category deviation detection.

Previously, we reported enhanced P3 amplitudes to between-category deviations among high and low probability events. Here, we tested the effects of a within-category difference. Subjects performed a go/no-go button press task as they viewed repeated, randomly-ordered presentations of nine double-digit numbers. Eight numbers fell within a prescribed range (42-49, standards); prior to testing, subjects selected one standard number for later recall. A ninth, out-of-range (91, deviant) number was also included. Subjects were tested under two conditions, in which they responded either to one (low response probability) or to seven (high response probability) standard nonselected numbers, designated as targets. Relatively larger P3s were consistently apparent only when the deviant nontarget was associated with a low probability response to a nontarget. There was a selective effect of nontarget response probability on P3 amplitude to the deviant nontarget. Our results indicate that within-category deviation detection is facilitated by "controlled" attention to the structure of the stimulus field.

Adolescent↗
PubMed1982

Fetal habituation in high-risk pregnancies.

Habituation is a basic form of learning and probably requires an intact central nervous system. Habituation in the behavioural response to vibration in 40 normal human fetuses was compared with that in a group of high-risk pregnancies with an increased risk of fetal neurological damage. Highly significant differences in habituation patterns between the high-risk groups and normal control subjects were found. This test may offer a method of assessing the integrity of the fetal central nervous system.

Anencephaly↗