Errorless learning (EL) is a commonly used technique in memory rehabilitation given the advantage it has for patients with amnesia over traditional learning, which allows them to make errors and takes advantage of the mistakes. However, there is evidence that EL outcomes may vary significantly across patients depending on various factors such as injury severity, the specific learning task or the neuropsychological profile of the patient [1].

Is errorless learning then the best treatment option for memory deficits? What about for other deficits such as executive function impairment?

In this post, I will review the cognitive mechanisms that have been proposed to explain the advantage of errorless learning over errorful learning (EF) in memory rehabilitation, because this update may be useful for determining when this type of technique might be beneficial in the cognitive neurorehabilitation of patients with impairments.

What is errorless learning?

Errorless learning refers to a training method that prevents a person from making mistakes while he/she is learning a new skill or acquiring new information. By contrast, in traditional learning, making mistakes is part of the learning process [e.g., 1].

In the clinical setting, this approach is applied as a principle to be followed in the rehabilitation of patients with severe memory impairments, given that they are deemed to be at particular risk for remembering mistakes as correct responses (and not learning from the mistakes they make).

Although there are different procedures, the standard errorless learning method consists of presenting target information to the patient for study (e.g.,pictures of objects that are faded out or just word stems), giving them the correct answer immediately after, and then ensuring that the response is encoded in some way (by repeating it, writing it down, etc.). This approach involves basing learning exclusively on the (repeated) processing of information and reduces the probability of errors by preventing participants from attempting to retrieve target responses from long-term memory.

However, we know that one of the most well-established principles of learning and memory is that retrieval practice per se contributes to the recall of information (and not due to the extra processing it requires [2, 3]). Therefore, errorless learning—to the extent that it is restrictive and preempts attempts at retrieving information—is a passive form of learning that does not maximize retrieval practice effects. Trial-and-error procedures, on the other hand, encourage patients to make retrieval attempts, therebyfacilitating the consolidation of learning.

A recent systematic review of studies examining the effectiveness of errorless learning when compared to errorful learning in other memory-impaired populations[1] concluded that, while the evidence generally suggests that the errorless learning approach may be successful in the rehabilitation of memory impairment, not all groups of people with memory problems seem to benefit more from learning under errorless than errorful conditions, and that there are also some limitations associated with errorless learning.

Why is errorless learning then considered to be the method of choice for the rehabilitation of memory disorders?

The cognitive mechanisms of the errorless learning advantage

Errorless learning was originally developed for the rehabilitation of patients with severe anterograde amnesia after having observed that, despite severe explicit memory impairments, patients showed intact procedural memory [4, 5].

The first studies comparing memory performance after errorless and errorful learning [4, 5] found that patients with amnesia did indeed recall more words when trained not to make errors than when an errorful learning procedure was employed.

These first studies argued that errorless learning was superior to errorful learning because EL depends on implicit memory: during implicit learning,encoding occurs due to the strength of the response to the stimulus, irrespective of whether the response is correct or incorrect; hence implicit memory does not distinguish between errors and correct responses but between strong and weak associations. Therefore, the authors of these studies concluded that error elimination improves learning in amnesic patients because the elimination of errors during learning avoids the misleading influence of their activation.

Since then, the debate over the mnemonic mechanisms of the errorless learning advantage has mainly revolved around two positions: whether this advantage can be explained in terms of implicit or explicit memory [e.g., 1, 6, 7].

The explanation in terms of implicit memory claims that what prevents amnesic patients from remembering the mistakesthey make is their impaired explicit memory: in the absence of such recollection, these patients continue to make the same errors on subsequent trials since their learning relies on implicit memory processes.

The explanation in terms of explicit memory argues that patients with amnesia benefit more from errorless than errorful learning because theyexploit the residual explicit memory. This argument is based on the observation that patients with better preserved explicit memory performed better after errorless learning than patients with more severe explicit memory impairments [7].

A third explanation alludes to source memory, which involves remembering the context of an event dissociated from the recollection of its content [1, 7]. According to this approach, the deterioration of source memory would cause specific difficulty in distinguishing the items learned through feedback provided by the therapist from the self-generated items, leading to confusions between target information and errors. Thus, when source memory is impaired, this hypothesis predicts that errorless learning will be a better option than errorful learning for it avoids the interference of errors during recall.

Other possible applications of errorless learning: attention and executive deficits

The ability to monitor and detect errors, and to modify behavior on the basis of feedback therefore seem central to explanations of why errorless learning is more effective in patients with amnesia than trial-and-error learning [1].

On the other hand, memory for the source is thought to be mediated in part by the frontal lobe [1, 7], in particular by the left and right prefrontal cortices, areas which are involved in the operation of attentional and executive control processes, as well as in error detection and adjustment by comparing incoming inputs or stimuli with internal long-term memory representations.

All this has led some authors to consider the involvement of executive functions in the errorless learning advantage. Recently, attention and executive control processes that might influence information processing, working memory, and episodic memory have been suggested to play a key role [1]. Specifically, the authors suggest that, through the allocation of sustained attention resources, executive control processes “guide stimulus processing, allow goal-oriented access and manipulation of internal representations, and support the maintenance of those representations. Therefore, these processes allow comparison ofexternal stimuli with stored internal representations and the integration of memory for the content of an event with memory for the source or context of an event (…). Consequently, the effectiveness of the approaches (…) may vary in part depending on the degree to which they make appropriate demands and support the optimal functioning of attention processes” [1].

Therefore, according to this study, given that attention processes and error monitoring are critical for learning, and since these are compromised in neurological patients, it may be important to consider the application of errorless procedures not only in patients with memory disorders, but also in the rehabilitation of patients with sustained attention and/or executive function deficits.

Bibliography

1. Clare, L.& Jones, R. S. (2008). Errorlesslearning in the rehabilitation of memory impairment: A critical review. NeuropsycholRev, 18:1-23.
2. Carrier, M. &Pashler, H. (1992). The influence of retrieval on retention. Memory and Cognition, 20: 633.
3. Ruíz Rodríguez, M. (2004). Las caras de la memoria. Madrid, España: Pearson Educación.
4. Glisky, E. L., Schacter, D. L., &Tulving, E. (1986). Learning and retention of computer-related vocabulary in memory-impaired patients: method of vanishing cues. Journal of Clinical and Experimental Neuropsychology, 8(39): 292-312.
5. Baddeley, A.& Wilson, B. A. (1994). When implicit learning fails: amnesia and the problem of error elimination. Neuropsychologia, 32(1): 53-68.
6. Anderson, N. D. &Craik, F. I. (2006).The mnemonic mechanisms of errorless learning. Neuropsychologia, 44(14): 2806-13.
7. Anderson, N. D., Guild, E. B., Cyr, A. A., Roberts, J., &Clare, L. (2012).Contributions of frontal and medial temporal lobe functioning to errorless learning advantage. NeuropsycholRehabil, 22(2):169-86.