Amotz Perlman

Construction safety training using immersive virtual reality

Construction workers’ ability to identify and assess risks is acquired through training and experience and is among the key factors that determine their behaviour and thus their safety. Yet researchers have questioned the effectiveness of conventional safety training. This research tested the hypotheses that safety training in a virtual reality (VR) construction site would be feasible and more effective, in terms of workers’ learning and recall in identifying and assessing construction safety risks, than would equivalent training using conventional methods. Sixty-six subjects were provided training in construction safety and their safety knowledge was tested prior to the training, immediately afterward, and one month later. Half of the subjects received traditional classroom training with visual aids; the other half were trained using a 3D immersive VR power-wall. Significant advantage was found for VR training for stone cladding work and for cast-in-situ concrete work, but not for general site safety. VR training was more effective in terms of maintaining trainees’ attention and concentration. Training with VR was more effective over time, especially in the context of cast-in-situ concrete works. Given the need for improved training and the advantages of training using VR, incorporation of VR in construction safety training is strongly recommended.

Interactions Between Encoding and Retrieval in the Domain of Sequence-Learning

In this article, the authors propose to characterize sequence learning in terms of automatic versus non-automatic processing and to apply this contrast independently to knowledge acquisition and retrieval. In several experiments of sequence learning, automaticity of both the acquisition and retrieval of the acquired knowledge was independently assessed. It was found that the sequence learning order can be demonstrated under all combinations of knowledge acquisition and retrieval. In particular, at least in the simple sequences the authors used, this applies in cases in which both the acquisition and the retrieval of knowledge are strictly automatic--that is, when neither is required for the task nor beneficial to deliberate behavior. The proposed framework has implications for the notion of sequence learning and the investigation of learning in general.

Measuring category intuitiveness in unconstrained categorization tasks

What makes a category seem natural or intuitive? In this paper, an unsupervised categorization task was employed to examine observer agreement concerning the categorization of nine different stimulus sets. The stimulus sets were designed to capture different intuitions about classification structure. The main empirical index of category intuitiveness was the frequency of the preferred classification, for different stimulus sets. With 169 participants, and a within participants design, with some stimulus sets the most frequent classification was produced over 50 times and with others not more than two or three times. The main empirical finding was that cluster tightness was more important in determining category intuitiveness, than cluster separation. The results were considered in relation to the following models of unsupervised categorization: DIVA, the rational model, the simplicity model, SUSTAIN, an Unsupervised version of the Generalized Context Model (UGCM), and a simple geometric model based on similarity. DIVA, the geometric approach, SUSTAIN, and the UGCM provided good, though not perfect, fits. Overall, the present work highlights several theoretical and practical issues regarding unsupervised categorization and reveals weaknesses in some of the corresponding formal models.

Hazard perception of motorcyclists and car drivers

The current study compares hazard perception (HP) performance of 50 male drivers with and without a motorcycle license in order to generalize results. A video-based HP test, measuring reaction times to traffic scenes, was administered to these two groups of drivers. Participants with a motorcycle license performed better than participants without a motorcycle license. ANOVA indicated that learning improved linearly for participants with a motorcycle license but not for participants without a motorcycle license. No evidence that HP was predicted by age was found. HP scores for drivers who reported previous involvement in an accident were lower than for those who reported not being involved in an accident. The results are discussed in the context of sensitivity and response bias models.

Unsupervised Categorization in a Sample of Children with Autism Spectrum Disorders.

Studies of supervised Categorization have demonstrated limited Categorization performance in participants with autism spectrum disorders (ASD), however little research has been conducted regarding unsupervised Categorization in this population. This study explored unsupervised Categorization using two stimulus sets that differed in their difficulty of Categorization according to the simplicity model. ASD participants displayed a greater tendency to categorise according to one dimension as compared with mental-aged matched participants in the easily categorised sets, but both ASD and Control groups became more prone to one-dimensional sorting as the difficulty of the Categorization task increased. These results are discussed in terms of the processes underlying over-selective responding.

Task-Relevant Chunking in Sequence Learning.

In the present study, we investigated possible influences on the unitization of responses. In Experiments 1, 2, 3, and 6, we found that when the same small fragment (i.e., a few consecutive responses in a sequence) was presented as part of two larger sequences, participants responded to it faster when it was part of the sequence that was presented more often. This indicates that chunking can be driven by task-relevant considerations, as opposed to co-occurrence. The results are discussed in the context of chunking theories and the relevant motor learning literature.

Supervised versus unsupervised categorization: Two sides of the same coin?

Supervised and unsupervised categorization have been studied in separate research traditions. A handful of studies have attempted to explore a possible convergence between the two. The present research builds on these studies, by comparing the unsupervised categorization results of Pothos et al. (2011; Pothos et al., 2008) with the results from two procedures of supervised categorization. In two experiments, we tested 375 participants with nine different stimulus sets and examined the relation between ease of learning of a classification, memory for a classification, and spontaneous preference for a classification. After taking into account the role of the number of category labels (clusters) in supervised learning, we found the three variables to be closely associated with each other. Our results provide encouragement for researchers seeking unified theoretical explanations for supervised and unsupervised categorization, but raise a range of challenging theoretical questions.

Automatic mode of acquisition of spatial sequences in a serial reaction time paradigm

In this study, the acquisition of spatial sequences was investigated. It was found that the acquisition of spatial sequence order could be acquired under strictly automatic conditions, namely, when not being part of the task requirement nor when being beneficial to purposive behavior. The results are discussed from the perspective of the difference between spatial versus non-spatial sequence learning.

The notion of contextual locking: Previously learnt items are not accessible as such when appearing in a less common context

We examined the effect of context on the learning of spatial coding in four experiments. Two partially overlapping sets of stimuli, which had the very same stimulus–response spatial coding, were presented in unique contexts. Results show contextual locking—that is, response times to the very same item in a more common context (80%) were significantly shorter than those in a less common context (20%). Contextual locking was obtained both when the context was more salient (Experiments 1 and 2) and less salient (Experiments 3 and 4). In addition, results were obtained even when contextualization seemed less necessary (Experiments 2 and 4). Binding of information to context is discussed in relation to chunking, transfer effects, and practical applications pertaining to professional training.

Are all changes equal? Comparing early and late changes in sequence learning

Although it is known that a change in a learned motor sequence slows performance down, it is yet unknown if this impairment varies depending on whether the changed element is early or late in the sequence. In Experiment 1, we showed greater impairment in performance when changing the third vs. the sixth element in a 7-element sequence. The impairment was greater for the deviant and the following elements than for the preceding ones. In Experiment 2, we replicated the results of Experiment 1 and expanded them by showing that a change in the third element of a 4-element sequence produced similar results to those of the late change condition in the long 7-element sequence. It is proposed that during practice, associative relations between the sequence elements are formed together with the representation of the whole chunk. Following the change in sequence, the chunk representation is impaired and performance mainly reflects the associative links between the elements. An early change hampers these associative relations to a greater extent than a late change, and as a consequence slows performance down more than a late change does. The implications and advantages of such a mechanism are discussed.