When the ordinary seems unexpected: evidence for incremental physical knowledge in young infants

According to a recent account of infants' acquisition of their physical knowledge, the incremental-knowledge account, infants form distinct event categories, such as occlusion, containment, support, and collision events. In each category, infants identify one or more vectors which correspond to distinct problems that must be solved. For each vector, infants acquire a sequence of variables that enables them to predict outcomes within the vector more and more accurately over time. This account predicts that infants who have acquired only a few of the variables in a sequence should err in two ways in violation-of-expectation tasks: (1) they should view impossible events consistent with their incomplete knowledge as expected (errors of omission), and (2) they should view possible events inconsistent with their incomplete knowledge as unexpected (errors of commission). Many reports have shown that infants who have not yet identified a variable in an event category produce errors of omission: they fail to view impossible events involving the variable as unexpected. However, there has been no report revealing errors of commission in infants' responses to possible events. The present research examined whether 3- and 2.5-month-old infants, whose knowledge of occlusion events is very limited, would produce errors of commission as well as errors of omission when responding to these events. At 3 months of age, infants viewed as unexpected a possible event in which a tall cylinder became visible when passing behind a tall screen with a very large opening extending from its upper edge. At 2.5 months, infants viewed as unexpected a possible event in which a tall cylinder became visible when passing behind a tall screen with a very large opening extending from its lower edge. These findings provide a new kind of evidence for the incremental-knowledge account, and more generally for the notion that infants, like older children and adults, engage in rule-based reasoning about physical events.     

Errors on a computer task and subclinical symptoms of attention‐deficit/hyperactivity disorder (ADHD)

Previous reports have found increased error rate for children with attention‐deficit/hyperactivity disorder (ADHD ) on response time (RT ) computer tasks. Here we attempt the conceptual replication and extension of two studies that examined error rate in a general population of children (N = 203). Study 1 followed Johnstone and Galletta but considered associations between scores on a dimensional measure of ADHD symptoms (rather than comparing those with or without an ADHD diagnosis) and the frequency of commission and omission errors. Study 2 followed Shiels, Tamm & Epstein and examined post‐error adjustment in the same group of children as for Study 1. Study 1 did not replicate previous findings of no increase in errors of commission in those with higher ADHD symptoms (Johnstone & Galletta). Instead, we found that younger children with lower ADHD symptoms were more likely to make commission errors, while omission errors did not vary with age. Study 2 replicated the previous finding of less RT slowing in children with more ADHD symptoms, extending this finding to a general population of children. Namely, as ADHD symptoms increase, RT slowing is less likely, putting children with higher ADHD symptoms at risk of additional errors. Overall, we extend previous ADHD research to typically developing children with ADHD symptoms.     

Relations Between Continuous Performance Test Performance Measures and ADHD Behaviors

The Conners' Continuous Performance Test (CPT) is a neuropsychological task that has repeatedly been shown to differentiate ADHD from normal groups. Several variables may be derived from the Conners' CPT including errors of omission and commission, mean hit reaction time(RT), mean hit RT standard error, d', and . What each CPT parameter actually assesses has largely been based upon clinical assumptions and the face validity of each measure (e.g., omission errors measure inattention, commission errors measure impulsivity). This study attempts to examine relations between various CPT variables and phenotypic behaviors so as to better understand the various CPT variables. An epidemiological sample of 817 children was administered the Conners' CPT. Diagnostic interviews were conducted with parents to determine ADHD symptom profiles for all children. Children diagnosed with ADHD had more variable RTs, made more errors of commission and omission, and demonstrated poorer perceptual sensitivity than nondiagnosed children. Regarding specific symptoms, generalized estimating equations (GEE) and ANCOVAs were conducted to determine specific relationships between the 18 DSM-IV ADHD symptoms and 6 CPT parameters. CPT performance measures demonstrated significant relationships to ADHD symptoms but did not demonstrate symptom domain specificity according to a priori assumptions. Overall performance on the two signal detection measures, d' and , was highly related to all ADHD symptoms across symptom domains. Further, increased variability in RTs over time was related to most ADHD symptoms. Finally, it appears that at least 1 CPT variable, mean hit RT, is minimally related to ADHD symptoms as a whole, but does demonstrate some specificity in its link with symptoms of hyperactivity.     

Errors of Omission and Commission during Alternative Reinforcement of Compliance: The Effects of Varying Levels of Treatment Integrity

We conducted two experiments to evaluate the effects of errors of omission and commission during alternative reinforcement of compliance in young children. In Experiment 1, we evaluated errors of omission by examining two levels of integrity during alternative reinforcement (20 and 60 %) for child compliance following no treatment (baseline) versus treatment at full (i.e., 100 %) integrity. Results indicated that compliance varied according to the level of integrity in place. In addition, compliance in the 60 % integrity condition was high and stable when it followed baseline, but was substantially lower for one participant and slightly lower for a second participant when it followed the full integrity condition. In Experiment 2, we evaluated errors of commission. For three participants, we compared treatment at full integrity to a condition in which errors of commission were made on every trial (i.e., 0 % integrity). For one of these three participants, we also compared treatment at full integrity to baseline and to a condition in which errors of commission were made on 50 % of trials. Results of all four evaluations again indicate that compliance varied according to the level of integrity in place: compliance was low in both the 0 and 50 % integrity conditions, regardless of the preceding condition. These results suggest that during alternative reinforcement of compliance, the effect of occasional errors of omission may depend on the immediately preceding context but that errors of commission are more detrimental.     

Co‐Witness Influence on Children's Memory Reports: The Difference is in the Details1

This study examined the effect of social influence on children's witness reports, with respect to a number of details varying in centrality. Children (N = 115; age = 10 years, 4 months to 13 years, 8 months) were interviewed about a personally experienced event. Half of the children were interviewed together with a confederate who answered the interview questions before the child did, while the other half were interviewed alone. Children were influenced by the confederate's answers to withhold some critical details observed (omission errors), but not to add details not observed (commission errors). When the children were asked to follow up on their reports, truthful reports contained more information than did false reports.     

The omission strategy

People are more willing to bring about morally objectionable outcomes by omission than by commission. Similarly, people condemn others less harshly when a moral offense occurs by omission rather than by commission, even when intentions are controlled. We propose that these two phenomena are related, and that the reduced moral condemnation of omissions causes people to choose omissions in their own behavior to avoid punishment. We report two experiments using an economic game in which one participant (the taker) could take money from another participant (the owner) either by omission or by commission. We manipulated whether or not a third party had the opportunity to punish the taker by reducing the taker's payment. Our results indicated that the frequency of omission increases when punishment is possible. We conclude that people choose omissions to avoid condemnation and that the omission effect is best understood not as a bias, but as a strategy.     

An electrophysiological study of school-aged children with a history of failure to thrive during infancy

Sixty-five subjects, ages 8 to 12, participated in a visual electrophysiological study. Twenty-two of the subjects had received a diagnosis of nonorganic failure-to-thrive (FTT) before the age of three. The remaining 43 subjects had no history of FTT and served as Controls. IQs were obtained with the abbreviated WISC-III, and the Controls were split into two groups, LO IQ and HI IQ, to provide a LO IQ Control group with an average IQ equivalent to the FTT group. Event-related brain potentials (ERPs) were recorded from five scalp locations during a cued continuous performance task (CPT). Subjects had to press a button every time they saw the letter “X” following the letter “A” (50 targets out of 400 stimuli). During the CPT, the FTT subjects made marginally more errors of omission to targets than the LO IQ Control group and significantly more errors of omission than the HI IQ Control subjects. The groups did not differ significantly on errors of commission (false alarms) or reaction times to targets. ERP averages revealed a group difference in amplitude in a late slow wave for the 50 non-X stimuli (false targets) that followed the letter A. This difference was greatest over frontal sites, where the FTT group had a more negative going slow wave than each control group. Late frontal negativity to No Go stimuli has been linked with post-decisional processing, notably in young children. Thus, the FTT subjects may have less efficient inhibitory processes, reflected by additional late frontal activation. *** DIRECT SUPPORT *** A31BB040 00006     

An electrophysiological study of school-aged children with a history of failure to thrive during infancy.

Sixty-five subjects, ages 8 to 12, participated in a visual electrophysiological study. Twenty-two of the subjects had received a diagnosis of nonorganic failure-to-thrive (FTT) before the age of three. The remaining 43 subjects had no history of FTT and served as Controls. IQs were obtained with the abbreviated WISC-III, and the Controls were split into two groups, LO IQ and HI IQ, to provide a LO IQ Control group with an average IQ equivalent to the FTT group. Event-related brain potentials (ERPs) were recorded from five scalp locations during a cued continuous performance task (CPT). Subjects had to press a button every time they saw the letter "X" following the letter "A" (50 targets out of 400 stimuli). During the CPT, the FTT subjects made marginally more errors of omission to targets than the LO IQ Control group and significantly more errors of omission than the HI IQ Control subjects. The groups did not differ significantly on errors of commission (false alarms) or reaction times to targets. ERP averages revealed a group difference in amplitude in a late slow wave for the 50 non-X stimuli (false targets) that followed the letter A. This difference was greatest over frontal sites, where the FTT group had a more negative going slow wave than each control group. Late frontal negativity to No Go stimuli has been linked with post-decisional processing, notably in young children. Thus, the FTT subjects may have less efficient inhibitory processes, reflected by additional late frontal activation.     

Legitimate lies: The relationship between omission,commission, and cheating

Across four experiments, we show that when people can serve their self‐interest, they are more likely to refrain from reporting the truth (lie of omission) than actively lie (lie of commission). We developed a novel online “Heads or Tails” task in which participants can lie to win a monetary prize. During the task, they are informed that the software is not always accurate, and it might provide incorrect feedback about their outcome. In Experiment 1, those in the omission condition received incorrect feedback informing them that they had won the game. Participants in commission condition were correctly informed that they had lost. Results indicated that when asked to report any errors in the detection of their payoff, participants in the omission condition cheated significantly more than those in the commission condition. Experiment 2 showed that this pattern of results is robust even when controlling for the perceived probability of the software error. Experiments 3 and 4 suggest that receiving incorrect feedback makes individuals feel more legitimate in withholding the truth, which, in turn, increases cheating.     

Assessing inattention and impulsivity in children during the Go/NoGo task

Behavioural performance in the Go/NoGo task was compared with caregiver and teacher reports of inattention and hyperactivity‐impulsivity in 1,151 children (N=557 boys; N=594 girls) age 9–10 years old. Errors of commission (NoGo errors) were significantly correlated with symptom counts of hyperactivity‐impulsivity, while errors of omission (Go errors) were significantly correlated with symptom counts for inattention in both caregiver and teacher reports. Cross‐correlations were also evident, however, such that errors of commission were related to inattention symptoms, and errors of omission were related to hyperactivity‐impulsivity. Moreover, hyperactivity‐impulsivity and inattention symptoms were highly intercorrelated in both caregiver (r=.52) and teacher reports (r=.70), while errors of commission and omission were virtually uncorrelated in the Go/NoGo task (r=.06). The results highlight the difficulty in disentangling hyperactivity‐impulsivity and inattention in questionnaires, and suggest that these constructs may be more clearly distinguished in laboratory measures such as the Go/NoGo task.     

Words fail: Lesion-symptom mapping of errors of omission in post-stroke aphasia

Impaired object naming is a core deficit in post-stroke aphasia, which can manifest as errors of commission – producing an incorrect word or a non-word – or as errors of omission – failing to attempt to name the object. Detailed behavioural, computational, and neurological investigations of errors of commission have played a key role in the development of neurocognitive models of word production. In contrast, the neurocognitive basis of omission errors is radically underspecified despite being a prevalent phenomenon in aphasia and other populations. The prevalence of omission errors makes their neurocognitive basis important for characterizing an individual's deficits and, ideally, for personalizing treatment and evaluating treatment outcomes. This study leveraged established relationships between lesion location and errors of commission to investigate omission errors in picture naming. Omission error rates from the Philadelphia Naming Test for 123 individuals with post-stroke aphasia were analysed using support vector regression lesion-symptom mapping. Omission errors were most strongly associated with left frontal and mid-anterior temporal lobe lesions. Computational model analysis further showed that omission errors were positively associated with impaired semantically driven lexical retrieval rather than phonological retrieval. These results suggest that errors of omission in aphasia predominantly arise from lexical–semantic deficits in word retrieval and selection from a competitor set.     

Young children's moral judgments of commission and omission related to the understanding of Knowledge or Ignorance

This study examined developmental change in young children's moral judgments of commission and omission related to mental states, especially knowledge or ignorance. 4–5 and 5‐ to 6‐year‐olds (n=67) made moral judgments about the tasks related to the understanding of knowledge or ignorance. The tasks were also composed of two types of acts: commission or omission. The results showed that the both age groups understood knowledge and ignorance, but that the older group made moral judgments based on this understanding more similar to adults compared to the younger group. There was not an age difference concerning whether the acts were of commission or omission. These findings indicate that there is no difference for young children in the difficulty in moral judgments of acts of commission and omission related to mental states, whereas there is a developmental difference in using the understanding of knowledge or ignorance for making moral judgments. Copyright © 2009 John Wiley & Sons, Ltd.     

Hypnosis,hypnotic suggestibility,memory, and involvement in films

Our research extends studies that have examined the relation between hypnotic suggestibility and experiential involvement and the role of an hypnotic induction in enhancing experiential involvement (e.g., absorption) in engaging tasks. Researchers have reported increased involvement in reading (Baum & Lynn, 1981) and music-listening (Snodgrass & Lynn, 1989) tasks during hypnosis. We predicted a similar effect for film viewing: greater experiential involvement in an emotional (The Champ) versus a non-emotional (Scenes of Toronto) film. We tested 121 participants who completed measures of absorption and trait dissociation and the Harvard Group Scale of Hypnotic Susceptibility and then viewed the two films after either an hypnotic induction or a non-hypnotic task (i.e., anagrams). Experiential involvement varied as a function of hypnotic suggestibility and film clip. Highly suggestible participants reported more state depersonalization than less suggestible participants, and depersonalization was associated with negative affect; however, we observed no significant correlation between hypnotic suggestibility and trait dissociation. Although hypnosis had no effect on memory commission or omission errors, contrary to the hypothesis that hypnosis facilitates absorption in emotionally engaging tasks, the emotional film was associated with more commission and omission errors compared with the non-emotional film.     

Children’s suggestion-induced omission errors are not caused by memory erasure

We explored whether children’s suggestion-induced omission errors are caused by memory erasure. Seventy-five children were instructed to remove three pieces of clothing from a puppet. Next, they were confronted with evidence falsely suggesting that one of the items had not been removed. During two subsequent interviews separated by one week, children had to report which pieces of clothing they had removed. Children who during both interviews failed to report that they had removed the pertinent item (i.e., omission error; n = 24) completed a choice reaction time task. In this task, they were presented with different clothing items. For each item, children had to indicate whether or not they had removed it. Significantly more errors were made for those removed items that children failed to report than for those they had not removed. This indicates that children’s suggestion-based omission errors are not due to erasure of memories.     

Children's moral judgments of commission and omission based on their understanding of second‐order mental states1

Abstract: Children's moral judgments about acts of commission and omission with negative outcomes were studied based on their understanding of mental states. Children (N = 142) in the first, third, and fifth grades made judgments about four tasks composed of two levels of mental states (first‐order or second‐order) and two types of acts (commission or omission). The results showed that the 7‐year‐olds responded considering only first‐order mental states, but the 9‐ and 11‐year‐olds also used second‐order mental states in their judgments. Whether the acts were commission or omission did not make a difference. These results indicate that children can make moral judgments regarding acts of commission and omission based on an understanding of second‐order mental states by approximately the age of 9 years.     

Omission bias and perceived intention in children and adults

Omission bias refers to the tendency to judge acts of commission as morally worse than equivalent acts of omission. Children aged 7–8 and 11–12 years, as well as adults, made moral judgements about acts of commission and omission in two conditions in which the protagonist obtained a self‐directed benefit. In the antisocial condition, the other person was harmed; in the selfish condition, the other person was not harmed. The results showed that adults and both age groups of children judged that the agent who did something (act of commission) was morally worse than the agent who did nothing (omission) for both antisocial and selfish conditions, although this judgement tendency was clearer in the selfish condition than in the antisocial condition. Agent intention was held constant across commission and omission, but most participants rated the intention of the agent who did something as stronger than that of the agent who did nothing. These results suggest that omission bias occurs regardless of differences in age and situation. In addition, perceived intention appears to change in conjunction with omission bias.     

A controlled clinical comparison of attention performance in children with ADHD in a virtual reality classroom compared to standard neuropsychological methods.

In this initial pilot study, a controlled clinical comparison was made of attention perforance in children with attention deficit-hyperactivity disorder (ADHD) in a virtual reality (VR) classroom. Ten boys diagnosed with ADHD and ten normal control boys participated in the study. Groups did not significantly differ in mean age, grade level, ethnicity, or handedness. No participants reported simulator sickness following VR exposure. Children with ADHD exhibited more omission errors, commission errors, and overall body movement than normal control children in the VR classroom. Children with ADHD were more impacted by distraction in the VR classroom. VR classroom measures were correlated with traditional ADHD assessment tools and the flatscreen CPT. Of note, the small sample size incorporated in each group and higher WISC-III scores of normal controls might have some bearing on the overall interpretation of results. These data suggested that the Virtual Classroom had good potential for controlled performance assessment within an ecologically valid environment and appeared to parse out significant effects due to the presence of distraction stimuli.     

Damage to the retrosplenial cortex produces specific impairments in spatial working memory

Mounting evidence indicates that the retrosplenial cortex (RSP) has a critical role in spatial navigation. The goal of the present study was to characterize the specific nature of spatial memory deficits that are observed following damage to RSP. Rats with RSP lesions or sham lesions were first trained in a working memory task using an 8-arm radial arm maze. Rats were allowed 5 min to visit each arm and retrieve food pellets and a 5-s delay was imposed between arm choices. Consistent with previous research, rats with RSP damage committed more errors than controls. In particular, RSP-lesioned rats committed more errors of omission (failing to visit an arm of the maze), but there were no lesion effects on errors of commission (revisiting an arm). Neither group of rats exhibited a turn bias (i.e., always turning a certain direction when choosing an arm). At the end of the training phase of the experiment, both groups had reached asymptote and committed very few errors. In the subsequent test phase, a longer delay (30-s) was imposed during some sessions. Both control and RSP-lesioned rats continued to make few errors during sessions with the standard 5-s delay, but RSP-lesioned rats were impaired at the 30-s delay and committed more errors of commission, consistent with an increase in taxing spatial working memory.     

The use of mixed modeling to evaluate the impact of treatment integrity on learning

Treatment integrity, or the degree to which an intervention is implemented as intended, is a critical feature of skill acquisition tasks. Single‐case design consistently demonstrates that low treatment integrity slows or inhibits learning, but the relative impact of different types of instructional errors, or the presence of multiple errors, is less clear. The present study utilized a multilevel modeling approach to evaluate the impact of type of error (omission versus omission and commission) and error component (reinforcer delivery versus feedback) on learning. Findings revealed that learning outcomes worsened based on the type of error and as the complexity of errors increased; more specifically, participants performed better when only a single type of error occurred and when only a single error component was manipulated. Additionally, individual characteristics contributed to learning outcomes, highlighting the use of multilevel modeling as a helpful tool to supplement single‐case design. The differential impact of integrity errors on learning may be due to timing of errors (i.e., commission errors more likely to occur early in learning) or how errors affect reinforcement schedule versus discriminative control.     

Strengthening encoding via implementation intention formation increases prospective memory commission errors

Prospective memory refers to the ability to remember to execute future intentions (e.g., taking medication with dinner). Although most prior research on prospective memory errors has focused on omission errors (i.e., failures to perform an intention in response to a target cue), there has been a recent surge in research on commission errors, the erroneous performance of a finished intention. Existing studies have examined factors at retrieval that lead to commission errors; the present study extends this research by investigating the impact of encoding strength. We found that relative to standard encoding, implementation intention encoding doubled the risk of commission errors in our laboratory paradigm for both young and older adults. This novel finding demonstrates the impact of encoding strength on commission errors and documents the potential challenges of deactivating the effects of implementation intentions upon completion of a prospective memory task.